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Full text of "Planning and management of aircraft pavement construction."

JDLEY KNOX LIBRARY 
WALPr ^GRADUATE SCHOOl 

OUT .... J-, ;i»43-5101 



PLANNING AND MANAGEMENT OF 
AIRCRAFT PAVEMENT CONSTRUCTION 



BY 
TIMOTHY SMITH 



A REPORT PRESENTED TO THE GRADUATE COMMITTEE 
OF THE DEPARTMENT OF CIVIL ENGINEERING IN 
PARTIAL FULFILLMENT OF THE REQUIREMENTS 
FOR THE DEGREE OF MASTER OF ENGINEERING 



UNIVERSITY OF FLORIDA 
SUMMER 1993 



260M9 



PLANNING AND MANAGEMENT OF 
AIRCRAFT PAVEMENT CONSTRUCTION 



BY 

TIMOTHY SMITH 
f 



A REPORT PRESENTED TO THE GRADUATE COMMITTEE 
OF THE DEPARTMENT OF CIVIL ENGINEERING IN 
PARTIAL FULFILLMENT OF THE REQUIREMENTS 
FOR THE DEGREE OF MASTER OF ENGINEERING 



UNIVERSITY OF FLORIDA 
SUMMER 1993 



O a o 9 ip 



DUDLEY KNOX LIBRARY 
NAVAL POSTGRADUATE SCHOOf 
MONTEREY CA 93943-5101 



TABLE OF CONTENTS 



INTRODUCTION 1 

PART I - MANAGEMENT AND PLANNING CONCEPTS 

CHAPTER 1 5 

MANAGEMENT AND PLANNING FROM 
THE OWNERS PERSPECTIVE 

CHAPTER 2 15 

MANAGEMENT AND PLANNING FROM 
THE DESIGNERS PERSPECTIVE 

CHAPTER 3 20 

MANAGEMENT AND PLANNING FROM 
THE CONTRACTORS PERSPECTIVE 

CHAPTER 4 27 

JOINT GOALS OF THE OWNER, 
DESIGNER & CONTRACTOR 



PART II - CONSTRUCTION CONSTRAINTS & WAYS 
CONTRACTORS OVERCOME THEM 



CHAPTER 5 30 

COORDINATION OF THE PROJECT SITE 
WORK BY THE OWNER 

CHAPTER 6 38 

CONTRACTORS RESOURCES 

CHAPTER 7 40 

ROLLER COMPACTED CONCRETE 

CHAPTER 8 42 

DOWEL BAR INSERTERS 

CHAPTER 9 45 

NEW CONCRETE CEMENT MATERIALS 



CHAPTER 10 47 

PORTLAND CEMENT CONCRETE ADMIXTURES 

CHAPTER 11 49 

ASPHALTIC CONCRETE ADDITIVES 

CHAPTER 12 55 

MOBILE HOTMIX HOPPER 

CHAPTER 13 57 

LASER GUIDED PAVERS 

CHAPTER 14 60 

COMPUTER AUTOMATION 

PART III - FUTURE OF AIRCRAFT PAVEMENT CONSTRUCTION 
64 



BIBLIOGRAPHY 69 



INTRODUCTION 

American travel habits have changed since the airline 
industry was deregulated 14 years ago. We now use air 
transportation almost as commonly as we do our cars. This 
growth has resulted in overcrowded airports and their 
infrastructure. More capacity is needed now but many oppose 
growth of airports in their "back yards." 

Many believe that airport construction today is like 
the highway program of the 1950' s. (1) Expansion of the 
nations airport network may mean tens of billions of dollars 
in construction over the next decade. 

Runways, aircraft aprons and taxiways are the heart of 
an airport. Other supporting structures including terminals 
and automobile access facilities are there to support the 
aircraft operation pavements. (2) Just as durability and 
performance are essential for smooth and safe travel on 
highways, so are effective long lasting runways vital to an 
airport's success. 



Any time repair or construction evolutions are taking 
place in and around runways there is a great chance for 
impacts to airport operations. Because of this construction 
in these areas must be carefully contemplated, planned and 
executed. This paper will examine management techniques 
used to carry out construction work in and around these 
aircraft support pavements and review many of the 
innovations that contractors and others are using to improve 
quality and reduce impacts to airport operations. 

Just as with any heavy construction evolution, 
extensive planning and organization must be carried out 
before any equipment can be brought on site. There are some 
notable differences between aircraft pavement construction 
and other heavy construction evolutions. First, significant 
and definable impacts to operations in not opening a runway 
for morning aircraft arrivals and departures can be 
identified in a much more quantifiable way than other types 
of construction. Secondly, the work often must take place 
in and around operating aircraft. Sometime low flying 
aircraft are directly over the construction operations. 
Extreme safety precautions and coordination with airport 
operations must take place. 



The remainder of this paper is divided into three 
parts. The first deals with the most important aspects of 
aircraft pavement construction, management and planning 
concepts. This section looks at the process from the owner, 
contractor and design professionals perspectives. 
Organization concepts, project scheduling and contract types 
are discussed. The second section looks at technical 
developments that are in use to improve productivity and 
minimize operational impact. Materials, equipment and work 
crew organization along with computerization is examined. 
The last section is a conclusion that also looks at the 
future of airport construction. 



PART 1 



MANAGEMENT AND PLANNING CONCEPTS 



CHAPTER 1 
MANAGEMENT AND PLANNING FROM THE OWNERS PERSPECTIVE 

The owner is the one who has the most to lose if 
aircraft pavement construction work is not accomplished 
properly. The owner is not just the physical plant manager 
or construction manager. He or she is the entity that runs 
all aspects of the runway operations including coordinating 
with the airlines, controlling aircraft traffic terminal 
operations, operations of passenger service functions and 
all other functions associated with running an airport. 
Success for the owner goes beyond quality workmanship and 
timely completion. Although these are both important, the 
airport management's paramount concern is with maintaining 
aircraft operations and minimizing the impact and disruption 
during the repairs or construction. 

With this primary concern in mind, the owner's physical 
plant organization will formulate a strategy for design, 
procurement and management of the pavement work. The 
airport authorities must look at their organizational size 



and their in house engineering capabilities and the amount 
and complexity of the work to determine the mix of how much 
of the planning, engineering and craft work can be done 
within the organization and how much will be done by 
outsiders. 

FIXED PRICE CONTRACTS 

The "traditional" approach of hiring an engineering 
firm to design the project as a Fixed Price contract then 
advertizing for a contractor has been the most common 
approach in the past and will likely continue to be the 
preferred strategy in the future. This procurement systems 
has many benefits. Because it has been used for so long, 
all parties that are involved understand the process and how 
they fit into the system. In theory the bidding process is 
based on economic supply and demand. The contract is 
awarded to the lowest bid contractor. Because cost is the 
only criteria for award, some of airport managements other 
goals including minimizing disruption of aircraft operations 
may not be addressed adequately. Other options are now 
available to the airport manager that may allow greater 
flexibility and capabilities to meet his or her objectives. 



MULTIPLE PARAMETER CONTRACTS 

One such procurement method is a selection process 
where multiple parameters are use to select the contractor. 
(3) Primarily cost, time and quality are used to as 
criterion to assess each bid. Other criteria can be added 
such a as safety, security and operational impact. The 
contract package must state the parameters that will be 
used, relative weights that each parameter has and the 
system used to measure them. 

As was indicated earlier, the owners overriding 
consideration during construction work is to minimize impact 
on aircraft operations. By including this criteria in the 
bid analysis less impact may be achievable. Different 
management organizations or new construction techniques are 
being used by some construction contractors that have will 
decrease operational impact and contract cost. 

For example, using the conventional system, a fixed 
price contract is written where the contractor is directed 
work on taxiway A first followed by runway 23R then taxiway 
B. This work could involved different work elements where 
phasing it like this will cost prospective contractors more 
than other phasing concepts. The airport operator felt he 
or she had to do the work this way to meet operational 



requirements. If on the other hand the operator clearly 
spelled out the operational requirements such as work on 
runway 23R must only take place from 9:00 pm till 5:00 am 
and the contractor must maintain a 100 ft clearance from the 
end of the runway during other times, and other necessary 
criteria, the contractor may be able to creatively look at 
the limiting requirements, his equipment and manpower 
constraints and develop a more economical phasing structure. 

By weighing his plan along with the other parameters, 
there may be a lower contract cost with all of the 
operational constraints being met. The major hazard here is 
in ensuring that all of the operational considerations are 
clearly spelled out in the contract package. Failure to do 
this will result significant additional modifications to the 
contract and claims by the contractor for additional time 
and money. 

UNIT PRICE CONTRACTS 

There are some circumstances where the more common 
lump-sum type of contract will not adequately function as 
the best avenue for construction. Often this is because 
the exact volume of the work can not be determined. This is 
very common in pavement projects. The owner may not have 

8 



the equipment or manpower resources to perform repair and/or 
maintenance work or he or she may be unsure of the level of 
subsurface repairs that will be required when he or she 
initiates the work. In these cases, unit-price contacts may 
be well suited to this type of work. 

Spot repairs to pavements can often be categorized into 
specifically types of repairs and be easily defined in a 
unit-price contract package. As an illustration, minor 
cracks 1/4 in. to 1 in can be defined as Type I cracks while 
ones greater than 1 in across can be defined as Type II. 
The scope of the work that the contractor can be clearly 
defined in the plans and specifications. Figure (1) shows 
examples of this. 

Unit-price contracts offer many of the advantages of 
conventional competitive bidding yet allows reasonable 
variation in the quantities of work items with less chance 
of formal change orders. The contract package must 
completely describe all types of repairs and provide to 
contractor an estimated quantity of each type of repair with 
a range of fluctuations of the estimate so he or she can 



TYPE I REPAIRS 



Existing 



".-■ ' .y : ■■ '.,- --i.i.- i / ; .:H;,l , ',,']. j ,-.' '. !;■":'■ : 






SUBBASE 



Pavement 
Repairs 




TYPE II REPAIRS 



Existing 





SUBBASE 



Pavement 
Repairs 







SUBBASE 



PORTLAND CEMENT CONCRETE 
JOINT SEALING FILLER COMPOUND 



Public Works "Busy Airport Rehabilitates Runway to increase 

service life." 
Figure 1 10 



understand the scope and complexity of the job. It is 
common for contracts to be a mixture of fixed-price and unit 
price work in the same contract. A contract could call for 
a fixed price overlay with joint and crack repairs being 
unit-priced. 

DESIGN-BUILD CONTRACTS 

Many types of construction lend themselves to combining 
the design and construction elements into one contract. 
This type of procurement has may have potential benefits 
over the conventional system including clearer transfer of 
liability, not-to-exceed pricing, construction cost savings 
and overall time savings. The few studies have been 
conducted on this type of procurement have provided 
conflicting results. One related study of Florida 
Department of Transportation design built pilot program 
found that sizable time savings were possible while cost 
variance was less clear to determine. (4) This study was not 
directed at aircraft pavement construction. Despite this 
there maybe some correlation between the two types of 
construction. The time savings may be worth the risks in 
some aircraft pavement construction cases. If there are 



11 



indications of imminent failure of critical pavement, then 
using this method may be prudent. In most less time 
critical cases using normal methods would be the most 
prudent . 

This method has it opponents who point to several areas 
that of concern. First is that contractors due not have the 
organization to provide the full design services needed to 
bid on this type of work. Likewise engineering firms do not 
have the trade knowledge to construct a project. This means 
that some type of joint venture arraignment is often 
required. Also bidding this work may be more expensive than 
normal contract solicitations. Some avenue for recovery of 
some part of the design costs should be found to ensure that 
smaller less experienced firms are not "priced out" of 
completion. 

COST-PLUS CONTRACTS 

There are several other contract types that are could 
be used for aircraft pavements in certain circumstances but 
common use is not the case nor will it likely be in the 
future . 



12 



Cost-plus contracts pay the contractor for his costs 
plus some calculation for additional funds based on a fixed 
fee, percentage of work done or some other formula. This 
type of contract is usually preferred if unusual problems 
are expected to be encountered, the owner desires to start 
work prior to design completion, or where the contract 
involves new technology or in a remote location. Most 
aircraft pavement work does not fall into any of these 
categories so using cost-plus contracts is not recommenced. 

PROFESSIONAL CONSTRUCTION MANAGEMENT 

The concept of Construction Management is new and may 
give the owner another approach to correcting his or her 
pavement problems. Professional Construction Management 
(CM) treats project planning, design and construction as 
integrated tasks. The use of CM gives the owner several 
advantages over other systems. First, it supplies 
construction expertise to all phases of construction. The 
construction. The construction manager provides an 
independent evaluation of cost, schedules, performance, and 
changes that keep the owner informed, allowing for timely 
decisions. Secondly, it allows for phased construction 
thereby reducing the overall project duration. This maybe 

13 



critical for aircraft pavement projects where large scale 
construction efforts are planned with thee need for 
concurrent heavy air operations. Finally, this procedure 
tends to replace the adversarial relationships associated 
with the traditional process, using a team approach. 



14 



CHAPTER 2 
MANAGEMENT AND PLANNING FROM THE DESIGNERS PROSPECTIVE 

The design professionals component in the process is to 
ensure that a quality design is developed that will minimize 
the impact to airport operations. In addition to the normal 
constructions specifications, he or she must clearly 
incorporate the operational constraints on construction in 
the contract package. Work involving aircraft pavements are 
very often space and time constrained. Because of this 
there are many specialized items that the designer must 
address in his specifications. (5) 

1. For the operational considerations, the owner will 
want the project to proceed in a speedy manor. 
Often airport operations will required multiple 
construction phases, limited working hours. 
Special routing of aircraft considering 
airline schedules, lead time for clearance of 
runway, taxiway, or apron, by construction 



15 



equipment, notification of schedule changes, and 
other constraints will have to be dealt with. 

2. Access to the construction site by the contractor 
personnel, for material deliveries, and equipment 
movements must be controlled. Crossing active 
operations ares may be needed and require special 
precautions Depending on the location of the 
construction site, and its proximity to operating 
runways, taxiways and aprons, this can be much 
more serious than other types of construction. 

3. Deposal of waste products and clean up 
requirements to eliminate Foreign Object Damage 
(FOD) from entering operational areas. 

4. Establish minimum distance restrictions for 
construction vehicles, workers and material in 
relation to runway, taxiways and navigational aids 
remaining in operations during construction. 

5. Temporary aircraft operational changes and there 
effect on the construction project including 
threshold displacement, temporary markings and 
lighting should be included. Maintenance 
responsibilities for these should be specified. 



16 



6. The parking of construction equipment and vehicles 
when not engaged in construction, during 
nonworking times should be specified. 

7. The allowable location contractors stockpiles, 
construction office and plant should be 
identified. The requirements for marking and 
lighting the construction area should also be 
indicated. 

8. Requirements for standby equipment for critical 
equipment 

All of these restrictions significantly increase the 
contractors costs. Failure to included them will either 
result in unacceptable operational impact and/or contractor 
claims for additional funds. 

The design professionals participation in the process 
does not end when he or she has completed the plans and 
specifications and provides them to the owner. He or she 
is the most knowledgeable one about the design intent and 
technical requirements. By responding in a timely manor to 
owner and contractor requests for information and 
clarification during construction, he or she will be able to 
keep work progress on schedule. 



17 



Site visits are just as critical in aircraft pavement 
construction as in other heavy construction projects. These 
visits allow the engineer to see that the work is proceeding 
as planned and in accordance with his or her specifications. 
It also educates him on the field's technical and 
operational problems. In addition to contractual and legal 
obligations after construction starts the should have some 
pride of ownership in his or her design. 

Normally the designer will be responsible for review of 
contractor submittal to ensure they comply with the 
requirements of the contract. Timely review is important to 
ensure the project remains on schedule. 

Due to the nature of the work and coordination with 
airport operations, full time site engineering is required. 
For many reasons this function may or may not be performed 
by the designer. The governmental or other organization 
that controls the airport may have an excellent construction 
services organization. Another engineering firm may be 
hired because some fear that a design error will be hushed 
up by the design agent. Communication with the contractor 
and the airport operational authorities is critical to the 
success of the project no mater who is chosen to be 
responsible for this phase of engineering. (5) 

18 



The construction industry is one of the most hazardous 
industry in the country. Designers have traditionally 
distanced themselves from responsibility for site safety. 
More governmental agencies and other organizations are 
requiring that design firms be responsible for the 
construction contractors job safety. Future court cases may 
force engineering firms to re-look at there roles. 

As was indicated previously, aircraft pavement 
construction often has significant time and space constrains 
placed on it. Because of this, there is a much higher 
chance of accidents and injury than many other types of 
construction. The fact that the engineers site personnel 
have no direct authority over the contractors employees, 
many legal authorities believe that by having the design 
firm in charge of safety oversight, safety rules will be 
better enforced. (5) 



19 



CHAPTER 3 
MANAGEMENT AND PLANNING FROM THE CONTRACTORS PERSPECTIVE 

Both the owner and his design agent have 
responsibilities to develop a complete design package. It 
is the contractors responsibility to carry out the work 
within the constraints and in an economical manor to ensure 
he makes a profit. His or her planning and workmanship is 
the most complex and challenging portion of the total 
process. By wisely controlling material, equipment and 
manpower costs the contractor will be able to successfully 
complete the project. 

In a recent project to construct a new runway for 
Atlanta's Hartsfield Airport, a joint venture by C.W. 
Mathews and Bellenger Corp completed the project, on time 
with minimal operational impacts. The project 
superintendent saw that planning was the key to success. He 
indicated that, "Planning our paving work... to keep 
everyone's crews on schedule has been the key to success... 



20 



It's hard to loss money when you keep the project on 
schedule - that is the real payoff for good project 
planning." (6) 
ORGANIZATIONAL STRUCTURE 

Each construction company has it's own manner of 
setting up and organizational structure to perform the site 
work. This challenge is faced with each new contract. 
Variations in goals, situations, and aircraft operational 
requirements dictate unique structures. 

Several basic principals should be reviewed to 
determine the best structure. To be effective organizations 
should: (7) 

1. Establish clear responsibilities for external 
interfaces with owner, design professionals, 
material suppliers, and aircraft operations 
personnel . 

2. Provide a single point of responsibility at the 
lowest practical level. 

3. Integrate craft, engineering, planning and 
materials resources at the lowest practical level. 

4. Establish and enforce craft discipline priorities 
consistent with the construction phase of the 
project. 

21 



5. Limit managerial spans of control. 

6. Assure clear and effective communications and 
reporting relationships. 

7. Assure most effective utilization of management, 
support and craft resources. 

Circumstances may dictate additions to these but this 
represents many of the criteria that should be addressed for 
nearly all organizations. Trade-offs among the criteria 
some times must be made to form the best possible 
organization. 

There are a huge number of possible organizational 
structures. Construction work involving aircraft pavement 
is specialized, but scope variations, contractor resources 
and the mix of repairs vs. new construction make delineation 
of the "best" structure impossible. The contractor must 
carefully look at all of his strength, weaknesses and 
resources to develop an organization that will best allow 
him or her to manage the project. 

EQUIPMENT MANAGEMENT 

Just as in most pavement related construction the work, 
aircraft pavement construction is heavy equipment dependent. 
Much of this equipment is specialized for specific pavement 

22 



operations can be utilized for little else. (8) In addition 
its high cost requires procurement and operations to be 
accomplished with great care. Too often contractors want to 
buy newer and bigger equipment. The rational for purchasing 
new is often either to replace the old or for expansion. 
While both are sound reasons, careful decision making must 
be done because the contractor will be committing 
considerable financial resources without guaranties of 
future work. He or she must weigh the marginal benefits of 
greater productivity and asses the reduction in maintenance 
required for the new equipment. Since very little else but 
paving can be done with this equipment, careful assessment 
of future market must be accomplished. Is the amount of 
airport pavement construction on the up swing due to the 
increase in passenger demand or will economic realities 
force governing bodies to defer further work? This question 
must be addressed to fully asses the profitability of new 
equipment purchases. To accurately bid a contract, one must 
know how much unit cost of equipment will be. All 
replacement, maintenance and other costs should be included. 



23 



PROJECT PLANNING 

Once a team has been formed, in depth project planning 
should be undertaken. The project manager, superintendent 
and other senior players need to develop a construction plan 
that address all constraints and will provide an end product 
at the lowest possible cost to ensure a reasonable profit. 
(9) This planning should be review site plans, 
specifications, operational constraints, safety concerns, 
existing pavement condition surveys (if available), 
equipment availability, manpower requirements, native 
materials, and methods of construction to determine the best 
method of accomplishment. (10) Figure (2) diagrams the 
process that contractors must undergo to develop their 
project plan. 

The amount of planning should be proportional to the 
complexity and cost of the project. Proper planning is 
critical in all cases though. Making the right decisions 
on resource use, construction methods and working around 
operational constraints will be much easier at this point 
than later. The cost of making changes in the plan will 
increase over time. 



24 



CONTRACTOR PROJECT PLANNING 



CONTRACT 
REQUIREMENT 



COMPANY 
EXPERIENCE 



BID PRICE/ 

CAPITAL 

AVAILABILITY 



PROJECT 
PLAN & 
SCHEDULE 



OPERATIONAL 
CONSTRAINTS 




COMPANY 
RESOURCES 



LABOR 



EQUIPMENT 



MATERIAL 



Figure 2 



25 



The second part of this paper will address how 
contractors are using the planning process to examine their 
human and equipment assets to meet the operational 
constraints of aircraft pavement construction projects and 
make a profit. 



26 



CHAPTER 4 
JOINT GOALS OF THE OWNER, DESIGNER & CONTRACTOR 
The success of an aircraft pavement construction 
project is heavily dependant on the owner, the designer and 
the contractor working and communicating closely with 
each other. All of the parties involved with aircraft 
pavement construction have their own specific goals for the 
project, but many common goals can be found. Some of the 
common goals for each major player that are found in most 
aircraft pavement projects are shown in table (1). (11) 

COMMON GOALS FOR AIRCRAFT CONSTRUCTION 



OWNER 


CONTRACTOR 


DESIGNER 


* QUALITY WORK 


* QUALITY PRODUCT 


* QUALITY DESIGN 


* MINIMAL OPS 


* REASONABLE PROFIT 


* ACCURATE 


IMPACT 




DEPICTION OF 




* NO LITIGATION 


OWNERS REQ'R 


* NO DISPUTES 








* ON SCHEDULE 


* REASONABLE 


* ON TIME WORK 


* NO REWORK 


PROFIT 


* NO REWORK 


* NO ACCIDENTS 


* NO DISPUTES 


* WITHIN BUDGET 




* NO ACCIDENTS 


* NO ACCIDENTS 







Woodrich, "Partnering: providing Effective Project Control" 
Table (1) 



27 



The owner wants to minimize operational impacts while having 
a quality product within budget that will last the design 
life with minimal future maintenance. The designer wants to 
provide the owner with a design that will meet his or her 
quality needs, budget and operational constraints. The 
contractor has pride in his work and wants to meet all 
contract requirements and make a reasonable profit on the 
job. 

Its a common misconception among owners and design 
professionals that contractors want disputes to increase 
profits. This is not the case, none of the parties want 
disputes. Disputes cost the contractor time and money to 
settle and takes away form there ability to manage their 
workload . 

This need for cooperation between all parties 
associated with this type of work makes partnering aircraft 
pavement construction ideal. Partnering can be best summed 
up as getting "back to the old way of doing business with a 
handshake and taking responsibility for what you do." 
Partnering formalizes this concept and fosters good 
relations between all parties. It allows all parties to see 
and understand the other's goals and needs. Because of the 
inherent need to work together to minimize operational 
impacts, their is a great likelihood that partnering will be 
used more often in the future for aircraft pavement 
construction . 

28 



PART II 



CONSTRUCTION CONSTRAINTS 
& WAYS CONTRACTORS OVERCOME THEM 



29 



CHAPTER 5 
COORDINATION OF THE PROJECT SITE WORK BY THE OWNER 

Coordination of all of the people involved with the 
process is of paramount concern. If the owner does not 
adequately coordinate the organization's involvement with 
the project, then significant operational impacts will 
likely occur along with adversarial relations with the 
contractor. Once the contractor has been determined and 
award notifications gave been given, the owners should first 
hold a pre construction conference with all parties 
concerned with the project to introduce each other. (12) 
This meeting, among all parties affected by the 
construction, should assist in a better understanding of 
potential problems and possible solutions. Just as in any 
other preconstruction conference the attendees include the 
owners construction representative, the contractor and any 
subcontractors, the design engineer, and representatives 
from various affected operations organizations. These 
operations organization encompass all airport management, 
airlines, fixed base operators, Airline Pilots Association, 
and FAA representatives consisting of Air Traffic Control 
personnel and other effected parties. (12) 

30 



The items discussed include many that are common to all 
construction projects such as quality control, material 
testing record keeping, labor law considerations and 
environmental controls. The additional considerations 
entailed with aircraft pavement construction mean that 
special emphasis should be given to several areas. This 
includes the need for continuing vigilance to identify and 
overcome hazards brought on by the space and time 
constrained work in and around operational aircraft. Also 
of concern is the need to fully return the area to 
operational capability at the end of each phase. This 
concerns is especially important when the work involves 
working nights and returning the area to aircraft operations 
the next day. 

Much of the detailed construction functions going on 
during aircraft pavement construction is the same as what 
goes on during many other types of construction. Asphalt 
paving operations for highways has many of the same 
construction techniques as paving aircraft pavements. Paving 
machine, rolling techniques and other aspects are similar. 
A major the difference lies not so much in the construction 
process but the location and special precautions that must 
take place during construction. 

In only the most rare circumstances are construction 
efforts undertaken unencumbered with a total closure of the 
airport. When this occurs the construction can go on with 

31 



less concern for the direct aircraft safety and operational 
impacts that they will have on the airport. Construction on 
entirely new airports is an illustration of this. While 
Denver's new airport is being constructed, the contractor 
does not have to concern himself with common problems such 
as phasing operations to complete work and remove equipment 
by the mornings flights. 

Sometimes emergency or other types of repairs are 
necessary that will completely close an airport. If the 
area(s) needing repair are on the primary runway(s), or an 
airport with only one runway, or at a critical juncture of 
multiple runways, complete closure maybe necessary. Closure 
will reduce the close coordination that is required to 
ensure operational safety. It is very likely that the time 
constraints imposed on the contractor will be very stringent 
to ensure that the airport operations resume as soon as 
practical. Because of this compressed time of performing 
work, construction safety becomes a significant concern. 

TIME CONSTRAINED CONSTRUCTION 

A more common situation involves short duration 
partial to full closure of air operations while construction 
efforts are undertaken. This Time Constrained Construction 
often is undertaken at night or other low aircraft volume 
times to reduce operational impacts. Often the contract 
will call for the contractor to start work in the late 

32 



evening and must have the work site capable of supporting 
operations by early the next morning. (13) 

Time constrains require close coordination between the 
contractor and the owner's construction representative. The 
owner's representative should be familiar with the air 
operations that normally occur at the airport and also how 
operations will be altered during the construction 
evolution. (14) 

Prior to authorizing the contractor to start the 
evenings work (or other specific time period), the owners 
construction representative must first check weather reports 
to determine if it is prudent to start work. In most 
pavement construction evolutions weather is an important 
aspect to be considered to ensure a quality product. In 
this case the owner's representative is not checking to 
determine if conditions are adequate for proper 
construction. He or she needs to look at the weather 
conditions to see how they will effect operations of the 
airport. Rain, wind changes or fog creeping in during the 
night may necessitate changes in runway use and limit the 
availability of the work are during that evening. 

During the planning phases the owner's representative 
will have discussed the proposed time constraints with the 
operational personnel at the airport including Air Traffic 
control personnel ,the airlines and FAA. The nature of 
flight operations is such that changes in operations are 

33 



likely for each individual evening. Because of this the 
representative should again check with the operations 
personnel to ensure that all arriving and departing flights 
would be completed prior to the contractors mobilization and 
start of work. Specific sketches of the evenings work 
should be provided to ensure they understand where the 
contractor will be working. 

The contractor should be informed of any potential changes 
in the airport operations. Delays in start or required 
completion times or suspension of work are possible and 
should be clearly understood by all. Some of these 
operational changes include: 

1. Arrival of aircraft after start of operations. 

2. Late departure of aircraft due to late arrival. 

3. Weather conditions requiring changes in the 
operations of runways or taxiways if the airport 
will not be closing during operations. 

At the start of the evenings work, both the owner's 
representative and the contractor should agree on the scope 
of the time periods work. The amount of work should be 
controlled and monitored to prevent and "over ambitious" 
work plan. The consequences of planning to much work are 
significant because of the impact on planned aircraft 
arrivals. This is especially critical for projects 
involving large scale repairs and replacements. 



34 



Safety and operational constraining information should 
be given to the contractor personnel before the start of the 
project and during it as necessary. 

At the completion of the evenings work and before 
opening the pavement for aircraft operations, the owners 
representative, operations officials and contractor 
superintendent should jointly inspect the area. This should 
include careful checking of transition between new and 
existing pavement, FOD removal, and equipment removal for 
operations areas. 

SPACE CONSTRAINED CONSTRUCTION 

Another common scenario of work is that only limited 
portions of a airport will be closed to aircraft while 
construction progresses. Also construction of expansion 
runways, taxiways and aprons at existing airports can be 
space constrained. Aircraft operations will continue in 
areas outside the construction site. Tight control is 
maintained on limiting construction activities to the 
runway(s), taxiway(s) and/or apron(s). Depending on the 
geometries of the aircraft support pavements, aircraft 
operations may come in close proximity to construction work. 
Low level overflights of aircraft are common situations that 
require consideration. 



35 



Access to the site should be carefully considered. 
Manpower, equipment and material must be brought to the 
site. In order to access many mid field work areas, the 
contractor may have to cross operational areas or otherwise 
impact airport operations. These transit routes must be 
carefully arranged with the idea of elimination, as much as 
feasible, the crossing operational pavements. If crossing 
is needed, all vehicles should be equipped with two-way 
radios and personnel should be briefed on required 
communications procedures prior to crossing. 

The actual work site should be carefully delineated to 
ensure that all construction people and equipment stay 
within it. No equipment should be allowed to leave the 
area without the owner's representatives consent. Special 
care should be taken to ensure that foreign object damage 
(FOD) material is cleaned up regularly and is not allowed 
outside the limits of the project works site. 

Just as is the case in time constrained work, safety 
and operational constrains should be given to the contractor 
personnel before the start of the project and during it as 
necessary. 

During the planning phase the owner's representative 
will have discussed the work site space constraints with the 
operational personnel at the airport including Air Traffic 
control personnel ,the airlines and the Federal Aviation 
Administration. The nature of flight operations is such 

36 



that changes in operations are likely and these changes 
could effect the location of the work. Because of this the 
representative should regularly check with the operations 
personnel to ensure that work location does not effect 
aircraft operations. Specific sketch of the work should be 
provided to operations personnel and updated periodically 
The contractor should be informed of any potential changes 
in the airport operations. Delays in availability of sites 
or suspension of work are possible and should be clearly 
understood by all. (14) 



37 



CHAPTER 6 
CONTRACTORS RESOURCES 

Just as in the case of planning and managing, the 
contractor has the most challenging and risking part to play 
in aircraft pavement construction. In order to compete the 
project within the contract reguirements and make a 
reasonable profit the contractor will have to ensure his or 
her competitiveness with others who are vying for the 
contract . 

In addition to ensuring a competitive organizational 
structure and precise control over the project various 
improvements to contractors eguipment and material are being 
developed to improve paving speed and quality. Many of the 
improvements do not result in a quantum leap forward in 
speed ease of use or quality. Also they do not radically 
change the technique that is used for pavement whether it is 
Portland cement concrete or asphaltic concrete. They do 
however represent significant enhancements in the 
construction process. (15) (16) Each improvement in itself 
refines the means and methods to make the contractor more 
competitive. This paper can not describe all of the 
innovations that institutions, manufactures and contractors 

38 



are developing. It will describe many of the ones that 
contractors are using now to improve there competitive edge 
and win contracts. 



39 



CHAPTER 7 
ROLLER COMPACTED CONCRETE 

Many people have realized long a go that if existing 
material could be reused, as base material the cost of 
construction new concrete pavement could be reduced. Very 
often this resource is not reused because of oversight or 
concern that the contractor will not be able to adequately 
compact it or otherwise does not have the technical 
knowledge to reuse it. Several companies have refined 
Roller Compacted Concrete (RCC) to reduce costs of 
construction . 

Madden Contracting & Material Co. Inc, was 
subcontracted by the prime, Hyman Construction Company to do 
the grading, base and paving for a new taxiway and apron 
area at Andrews Airforce Base. (17) The contract plans 
called for a 14 inch concrete pavement to be constructed 
over a new 8 inch granular base and 4 inch drainage course. 
As value engineering proposal, the subcontractor suggested a 
change to reduce the cost with no decrease in durability or 
strength. Rather than disposing of the existing pavement in 
a designated off site location, and importing virgin 
aggregate for the granular base, the subcontractor proposed 

40 



replacing the granular base with a 6 to 7 inch Roller 
Compacted Concrete (RCC) course to be constructed with the 
aggregate made from the old concrete pavement. 

The subcontractor found that they could set up their 
own portable crushing plant and recycle the old concrete 
economically. Using this crushed material along with virgin 
fill from the area that was originally designated as the 
disposal site, nearly all there base course requirements 
were met. The new mix design used 60 percent recycled 
aggregate, (1 1/2 in minus), 33 percent virgin aggregate, 7 
percent cement and water to bring the mixture to the optimum 
moisture content. 

The machine that was used to spread the recycled 
material was an asphalt paver adapted for RCC work. This 
machine shapes and extrudes the mix under its rear screed 
where it is compacted further by two oscillating tamping 
bars. Following this, vibratory drum rollers made passes to 
complete the compaction. 

Under the terms of the Value Engineering clause of the 
contract, the savings of $104,000 was divided between the 
federal government and Maddden. The change did not lengthen 
the contract completion time and provided a equally durable 
end product. 



41 



CHAPTER 8 
DOWEL BAR INSERTERS 

Several companies have developed dowel bar inserters on 
there paver machines to speed the process and provide better 
quality. Traditionally dowels have been manually placed 
using baskets at the joint location. During a recent 
project constructing a new runway at Cincinnati 
International Airport, the prime contractor, The Harper Co. 
incorporated this improvement on their paver's to pave at a 
rate of 7000 cubic yards per day with up to three paving 
trains. (18) The contract requirements called for closely 
spaced joints with 47 dowels phased per joint. This 
resulted in 2.8 bars being placed per running foot of slab. 
The Dowel Bar Inserters used for expansion joints were 
loaded with dowels on each side of the paver. From there 
the dowels dropped into slots in preparation for each joint. 
The paver operator pushes a button to release the dowels 
when the paver reaches the proper location. When the dowels 
ar dropped, four vibrating fingers push them onto the 
concrete. The Dowel Bar Inserter remains stationary as the 
paver continues to move forward. After the fingers have 
placed the dowels in there proper place, the Dowel Bar 

42 



Inserter returns to its original position and is ready to 
place the next set of dowels. A correcting beam smooths out 
the imperfections that are left from placing the dowel . A 
pair of Dowel Bar Inserters are located in the rear of the 
paver with one on each side. The bars are injected into the 
sides of the slab at the halfway point every 18 in on center 
with a hydraulic cylinder. This process not only saved time 
but it also eliminated raicrofracturing which could result 
from drilling to insert the dowels later. 

Another contractor Shelly and Sands Inc. has devised an 
efficient system for installing dowels in patching existing 
concrete pavement. (19) The company mounted an epoxy 
dispensing machine and multiple bit hydraulic drill on a 
backhoe. The backhoe's hydraulic systems provides power for 
both the dispenser and drill. 

Using conventional methods hand drills are used to 
drill holes; epoxy is mixed in buckets and allied to the 
dowel and the dowel is set in the hole. 

In this improved method, workers use the hydraulic 
drill to bore a 1 1/8 inch diameter hole in the existing 
concrete. The epoxy dispenser feeds an precisely 
proportioned two-part epoxy paste through a high pressure 
hose and hand held dispenser gun. Employee's inject the 
epoxy into the hole then inset the bars. Epoxy components 



43 



stay separate until they enter the mixer portion of the gun 
for blending. With mixed expoy commonly having a 15 minute 
usable life this saves 25 to 30 percent in wasted epoxy over 
conventional methods. 



44 



CHAPTER 9 
NEW CONCRETE CEMENT MATERIALS 

Improving the equipment performance is only part of the 
equation of faster placement of concrete and higher quality 
finished product. Improvements in the concrete cement 
material are ongoing at a similar pace as equipment 
improvements . 

A major concern that airport operators have is that 
they want to have a return to normal operations as soon as 
possible. Portland cement concrete takes time for an 
initial set to take place and for it to have cured to a 
useable point. Because of this many companies and 
organizations are looking for materials that will set faster 
when repairing existing concrete. 

One such product Pyrament developed by Lone Star 
Industries Inc. Concrete made from this cement achieves its 
fast high strength of 2500 psi in about four hours. This is 
done without addition of any admixtures. Normally the 
concrete can accept airline traffic in six hours. 

This product was recently used for repairing a 
6,300 ft runway at Yeager Airport in Charleston West 
Virginia. (20) Using conventional materials, the main 

45 



runway would have been closed for almost a week until the 
concrete gained enough strength to support aircraft traffic. 
To minimize the operational impact of this, Pyrament was 
used. The last jet to use the main runway lands at 11:00 pm 
each night. Following the aircraft's exit from the runway 
work crews move equipment to the runway to remove the 
existing damaged concrete, clear out holes, mix and place 
the concrete, score the runway groves clean up and remove 
their equipment. All of this was done in only three hours. 
The last batch of concrete was placed by about 3:00 am and 
the first plane took of a 9:30am the next morning. The 
entire project was accomplished with no operational impacts 
and no construction related traffic delays. 

Ideal Cement Co. developed a new product, Regulated Set 
Portland Cement which can be used to replace failed sections 
of concrete in a matter of hours. The preparation and 
placement of this product is the similar to Pyrament and not 
radically different from conventional Portland Cement 
Concrete. The concrete mixture sets within 45 minutes and 
reaches a compressive strength of 2500 psi in three hours 
and 6000 psi in two days. 

Products like these have a wide applications for repair 
and construction of aircraft pavement. It is very likely 
that many more fast setting products like this will come on 
the market in the near future. 



46 



CHAPTER 10 
PORTLAND CEMENT CONCRETE ADMIXTURES 

Admixtures that decrease the curing time of Portland 
Cement Concrete have been used for some time. Faster repair 
times and less impacts to airport operations offset these 
materials slightly higher costs. The most common is 
calcium chloride. When used in small quantities it acts as 
an internal curing agent, assisting in the hydration process 
and acceleration the chemical reactions. (21) Due to its 
corrosive effects on steel, there is limited use for many 
pavement construction applications. 

Many new chemicals with the same accelerating qualities 
are being developed for use in pavement repairs. (22) One of 
the best known one is Magnesium-phosphate based additives. 
These allow the concrete to set in as short a time as 15 
minutes and be ready for traffic in a few hours. Different 
mixtures are often available for use in various weather 
conditions including hot weather formulas which contain a 
retarder to ease work in warmer temperatures. 

These mixes have different mixing orders and mixing 
times than conventional concrete. To ensure a lasting 
repair, it is best to strictly follow the manufactures 

47 



directions. Magnesium based mixes have significantly 
shorter mixing times than portland cement mixtures. Mixing 
longer than necessary is not needed and will only reduce the 
amount of working time available. Because of this short 
time, the mixing operation should be located as close to the 
repair area as possible. To minimize waste one should only 
mix slightly more concrete than is reguired. 



48 



CHAPTER 11 
ASPHALTIC CONCRETE MIXING ADDITIVES 

Many authorities are continuing to look for ways to 
extend the life of asphaltic pavements at lower cost. 
Higher crude-oil prices, increased use of spot sources and 
more competition for oil derivatives mean that contractors 
are seeing a grater variety in asphaltic cements and their 
characteristics. Manufacturers are developing Polymers that 
could improve asphalt flexibility in low temperatures and 
rigidity under summer's heat. (23) When the right 
combination of asphalt and polymers is ascertained, often by 
trail and error, the polymer forms a lattice in the bitumen. 
The two material do not form a chemical bond but a molecular 
entanglement where the binder takes on some of the polymers 
properties . 

The goal of theses additives is to extend asphalt 
pavements performance properties throughout the anticipated 
working temperatures as high as 140 degrees F to as low as - 
-20 degrees F. Through this range, polymers are expected to 
remain pliable at processing temperatures and adhere the 
aggregate better. To protect from rutting and shoving, 
plastomeric polymers such as ethylene/vinylacetate 

49 



copolymer, ethylene/acrylic acid copolymers and acrylic ester 
copolymers are being used. These materials can raise 
asphalt softening temperatures by as much as 10 to 15 
degrees and make the mat more ridged in hot temperatures. 
Prevention of cold weather cracking can be achieved buy 
using elasometric polymers such as natural latex, 
styrene/butadien rubber, styrene/butadiene block polymers 
and neoprene. These materials can lower the temperature at 
which asphalt will break from 32 degrees to -10 degrees. 
Copolymers seem have the best attributes of the two 
different molecules to give a variety of performance 
characteristics . 

Table (2) provides some of the characteristics of some 
of the currently available polymers. (23) 

For the time being, polymers offer in some cases to 

many options. Not all polymers are compatible with all 
mixes. In addition there is some variability in cost. 
Polymers add from $1 to $5 per ton to the cost of the mix. 
Engineers who desire to specify polymers should work 
with many manufactures to design a system that meets their 
specific objective. The alternate is to buy asphalt already 
mixed with a polymer. The premixed products most 
manufactures are marketing usually differ from other 
polymers in that the pre mixed ones bond chemically with the 
asphalt. The companies engineer their mixtures according to 

50 



gradation of aggregate used and the purpose of the pavement. 
Mixes can be allied as slurries, overlays or even full depth 
sections. 

CHARACTERISTICS OF POLYMER-MODIFIED ASPHALT 



Modifier 


Unique Performance 


Deficiency 


Styrene/butadiene 
block copolymer 
(SBS) 


* outstanding 
toughness 

* excellent elastic 
recovery 


* mixing/blending 

* raelt storage 
stability 

* ductility 


Styrene/butadiene 
latex (SBR) 


* ductility 


* mixing/blending 

* melt storage 


Natural latex 


* aggregate retention 

* good ductility 


* mixing/blending 

* melt storage 
stability 


Polycloroprene 
( Neoprene ) 


* toughness 

* elastic recovery 

* torsional recovery 

* compatibility 


* ductility 

* lack of 
toughness 


Polyolefin 
(PE, PP, EVA) 


* modulus (stiffness) 

* aging resistance 


* mixing/blending 

* raelt storage 
stability 

* ductility 



Stewart, "Polymers 
Table (2) 



Pavements Miracle Additive ? n 



Micro-Surfacing is a versatile cold-mix paving system 
using polymers that was pioneered in Germany. (24) Micro- 
surfacing consists of as a mixture of dense-graded 
aggregate, asphalt emulsion, water and filler. Applications 
include increasing skid resistance, adding service life to 



51 



high-speed, heavy-traffic surfaces and filling wheel ruts up 
to 2 inches deep. This product can also create a new stable 
surface that better resists rutting and shoving in hot 
temperatures and cracking in cold temperatures. This 
technique was used to increase the service life of both 
primary runways at Naval Air Station Keflivik. It increased 
life to allow for design and funding of full scale 
overlaying that was ultimately required. 

Another idea for additions to asphalt mix that promises 
improved stability is Fiber-Reinforcement. (25) Adding 
several pounds of these si Ik- like polyester fibers may prove 
to be a practical method of improving asphalt stability. 
Research on this is ongoing in several locations including 
Clemson University. While inclusion of fibers has many 
positive benefits, performance appraisals over time and 
loadings, and an analysis of the economic feasibility 
studies still need to be accomplished. 

Clemson 's research examined the effects of 
homogeneously dispersed polyester fibers on the tensile 
strength of asphaltic concrete surface courses. They also 
investigated the effects of differing amounts of fiber, 
fiber size and length. They found that: 



52 



1. The tensile strength ratios of the fiber mixtures 
increased 1 to 3 3 percent as compared to the 
control mixture. 

2. The addition of fibers resulted in increased 
toughness of up to 26 percent in the dry condition 
and 100 percent in the wet condition. 

3. The mixture with 0.5 percent 1/2 inch, 30 denier 
fibers provided the most improvement in toughness 
and higher tensile strengths 

4. Inclusion of polyester fibers resulted in an 
increase in the optimum asphalt cement contents 
from 0.3 to 1.0. It also increased air void 
contents . 

The experiments included both batch plant and drum 
mixer investigations. In the batch plant tests, the fibers 
were well dispersed throughout the mix but there were also 
"balls" of fibers which marred and tore the surface of the 
pavement. Researchers believe that the "balls" occurred 
because the short time the fibers were in the bath plant's 
mixing chamber before the asphalt was added. This likely 
could have been eliminated if a separate feed to input the 
fibers simultaneously with the aggregates was added or a 
storage silo would have been used. 

53 



The second experiment took place at Columbia 
Metropolitan Airport. More than 300 tons of polyester 
fiber-reinforced pavement was placed in one area while a 
like amount was places in an area with similar traffic 
loading. Using the drum mixer, the fibers and aggregates 
were cascaded and blended for about 25 seconds as they 
traveled down a drum then were coated with asphalt. From a 
contractor standpoint, the only apparent problem that 
existed was with f inishability when the 1/2 inch fibers were 
used. When they switched to 1/4 inch fibers there were no 
problems and a good finished product was achieved. 

Only after more long term tests to determine how this 
product stands up over time will we will be able to 
determine if fiber reinforcement will have real potential to 
improve aircraft pavement placement. 



54 



CHAPTER 12 
MOBILE HOTMIX HOPPER 

As has been indicated earlier, speed and high 
production can be significant considerations in aircraft 
pavement construction. Contractors need to find ways to 
keep high production on their paver machines. One idea that 
some contractors are using is use of Mobile Transfer 
Vehicles (MTV) a intermediate storage of asphalt and 
aggregate mix. (26) Haul trucks convey hotmix to the MTV 
while both vehicles are on the adjacent slab. The MTV then 
transfers the hotmix to the paver machine while both move. 
This keeps the haul trucks off the prepared subgrade and 
allows the paver to move without stopping for each truck to 
back in. 

This type of vehicle was used for construction of a new 
shoulders for a new runway at Indianapolis Airport. The 
contractor, Grady Brothers Inc. used a Barber-Green built 
MTV able to hold up to 70,000 pounds of material or two 
truck loads. Using this vehicle, a supply buffer was 

55 



maintained for the paver. As many as 25 trucks brought the 
asphalt in from two to three plants, each about ten miles 
from the worksite. The trucks remained on the concrete slab 
with the MTV where they dumped into the hopper in less than 
a minute. This allows the trucks to stay on the concrete 
and therefor ramps did not have to be constructed for the 
trucks to drive down onto the subgrade. 

Production averaged 3000 tons per day with the paver 
and mobile transfer vehicle combination. With the MTV and a 
steady supply of trucks, the paver can proceed continuously. 
Non-stop paving increases production and yield a higher 
guality finished product. 



56 



CHAPTER 13 
LASER GUIDED PAVERS 

Conventional asphaltic paving practices usually require 
setting stringlines to set the grade for the pavers. This 
control method requires lengthy surveying crew set up and 
more time to accomplish the paving. Lasers offer time 
saving alternatives that also improve final grade control 
and overall quality. Reducing the amount of initial set up 
and nightly setup coupled with the increase in paver 
productivity makes laser use appealing to many contractors. 

The use of lasers for grade control normally involves 
setting up one or more laser transmitters that send out 
rotating beams. Laser receivers and control systems are 
attached to pavers. The devices on the paver read the 
transmitted laser signal and can automatically adjusts the 
screed height to the desired level. This allows the 
operator to fully control the thickness of the mat and make 
changes due to obstructions without slowing the paving 
process . 

57 



Recently Sarasota-Bradenton airport contracted with 
Gator Asphalt Co. to resurface their main 7000 foot runway. 
(27) The original design called for conventional 
stringline paving with a center line keel (crown) running the 
runway's full length with some minor vertical curves. The 
engineer's original design specified a slope down from the 
crown to the sides of 1 to 1 1/2 percent. Using 
stringlines, the pace of the work would have slowed to a 
point that the contractor would not have been able to pave 
the full width across the runway in one night. Employing 
stringlines and the original design would have reguired the 
contractor to: 

1. Pave a leveling course in the crown and placing 
wedge sections of asphalt to form transitions of 
the asphalt to form transitional sections from the 
crown sides down to the old existing runway. This 
is necessary because of the requirement that 
temporary wedges be installed for aircraft safety, 
to avoid sharp drop offs. 

2. Pave a surface course for each keel again with 
wedges on each side. 

3. Mill out the transition wedges on each side and 
pave the 37 ft wide side sections simultaneously. 

58 



The contractor proposed a value engineering change that 
redesigned the final asphalt grades for laser guided pavers. 
Working with the Airport authorities, the designer and the 
Federal Aviation Administration authorities, the contractor 
won approval. 

The new method enabled the Gator Asphalt Co. to pave 
full width each night across the 150 foot wide runway. 
Setting and resetting stringlines to work full width would 
have been nearly impossible within the five hours available 
for construction work each night. By using lasers to guide 
the pavers, the contractor estimated he cut 10 working days 
from the 110 day project. 



59 



CHAPTER 14 
COMPUTER AUTOMATION 

With there reduction in both cost and size, computers 
they have become a very common place part of nearly all 
segments of construction. This tendency toward more and 
more automation in work processes includes aircraft pavement 
construction. Currently most uses are directed more toward 
information tracking such as accounting information, 
personnel and equipment productivity, material receipt, and 
maintenance. (28) This trend will likely continue because 
of the real tangible benefits that contractors are seeing to 
these devices. More powerful software packages for 
scheduling and field office managerial functions will result 
in many more desk top and portable computers in the field 
over the next few years. 

Many new computer applications are in various stages of 
research, development and implementation. New applications 
deal much more with improvement of the construction 
processes and less with using the computer as a managerial 
tool. 



60 



The most expensive and critical part of the paving 
process is the paver machine. Whether the work involves 
asphalt of portland cement concrete, maintaining proper 
control over the functions of the equipment is paramount in 
timely execution of the work progress and ensuring a quality 
pavement . 

Many contractors and equipment manufactures are now 
producing new pavers or modifying existing ones to use 
computers and automate paver functions. As an example a 
Gomaco Co. has on the market a paver that incorporates many 
automation and computerization innovations that improve its 
product i on . (29) 

The paver has three on-board computers that coordinate 
the machines functions. One computer positioned in at the 
operators station controls pavement alignment and profile. 
Sensors trace profile from stringlines on each side of the 
paver while alignment is traced from the left one. 

The other two computers control the sequence of 
operations of the dowel bar inserter. One computer 
initiates the sequence of the cart distributing the dowels 
after the injection fingers have been withdrawn. The other 
activates the insertion and vibration of the dowels. This 
computer also measures the distance traveled by the paver 

61 



from sensors in the crawler and coordinates the triggering 
of the tie bar and dowel bar inserter operations based on 
those distances. In addition it controls the pan, and 
screed adjustments in transitions between tangents and 
curves. Control of the computer operation is fairly simple 
allowing the superintendent to adjust the spacing of random 
skewed joints. 

The use of computers to automate the work process will 
likely continue. Although automation does cost a 
significant investment, the achievable higher quality and 
higher production will be a major impetus for future 
developments 



62 



PART III 



FUTURE OF AIRPORT PAVEMENT CONSTRUCTION 



63 



What is the future of aircraft pavement construction? 
Does it make sense for contractors to invest in higher cost 
pavers that have high production, more crushers, and hot mix 
plants or should they gear themselves for a reduced workload 
in the immediate future? There is no clear answer to either 
of these guestions but some past trends and current 
political atmosphere may be some indication of future 
workloads and what direction airport pavement construction 
may go. 

The Federal Aviation Administration's most recent 
capacity plan says that 62 of the 100 leading airports have 
proposed runways or extensions with a total price tag of 
$6.5 billion. (30) With the public's dim view of higher 
taxes to pay for this and desire to reduce the national 
debt, normal federal funding may be difficult. Other 
traditional funding such as bond issues have egually little 
support. A new funding option opened due to 1991 federal 
legislation. (31) In this legislation airports were allowed 
to charge up to $3 per passenger that transits through their 
airport. This money may be used for specific improvement 
projects approved by the Federal Aviation Administration. 
This fee could raise nearly $1 billion per year for 
improvements . 

64 



As indicated in the introduction of this paper, airline 
deregulation played a major role in the increase in demand 
in aircraft use and therefor more need for runways, taxiways 
and aprons to support there aircraft. As can be seen in 
Figure (3), the rate of airline passenger traffic will 
continue to grow in the foreseeable future. (32) Although 
more passengers does not directly equate to more need for 
aircraft pavement it does indicate that changes in overall 
airport operations from a local , regional and national 
perspective will be required. 

Many airlines are buying larger heavier aircraft that 
reduce their cost per passenger. This reduces their cost 
but will result in more fatigue in aprons and other pavement 
structures. More robust pavement designs and slab 
thicknesses may be required in the future. These new planes 
often have a larger footprint therefor more apron space may 
also be required in many areas. 

When a local or regional government entity see 
overcrowding at their airport, their normal reaction is to 
find ways to expand there current facilities. This involves 
new runways, taxiways etc. In the extreme cases the 
decision may be reached to build a new complex such as 
Denver's new airport. The likelihood of this magnitude of 

65 



THE GROWTH IN AIRLINE PASSENGER TRAFFIC 



CO 

oc 

LU 

-z. 

LU 
CO 
CO 

£ 

LL 

o 

CO 



i ,000 
000 

4-00 
200 




DEREGULATION.1978 




1 QSO "1 Q"7"0 1 QQO 1 QQO 2000 



"Airports Scramble to Keep Pace with Growth", Highway & Heavy Equipment 

Figure 3 

66 



construction in the future is rather small. The 
construction industry should not rely on this type of 
massive projects for future livelihood. In many areas, 
expanding by construction of a new runway or extension of 
existing meets momentous opposition. Many people are 
calling for a long delayed new runway at Logan airport in 
Boston. The new runway would reduce aircraft delays that 
cost the airlines millions a year. Opposition centers 
mostly on lack of funding to support this project. (33) 
Long range plans call for construction of a new airport west 
of the city but once again funding is questionable 

The answer to many congestion problems may not be 
expansion of new runways but looking for other solutions. 
One of these would ideally solve may problems at minimal 
cost. The Department of Defence through the Base Closure 
Process is closing many unneeded air bases. Many of these 
are near congested areas and may provide an inexpensive 
solution the overcrowding. These facilities could be used 
to support local commuter traffic or air freight functions 
that currently take up airspace and ramp space at many 
airports . 



67 



Two good examples of this is Logan airport and Miami 
International airport. As mentioned earlier Logan is 
overcrowded and needs to expand. While converting ex- 
military air facilities to civilian use will cost money it 
will be cheaper than constructing new ones. The Base 
Closure process will likely result in closure of Naval Air 
Station South Weymoth, less than 15 miles south of Logan 
airport. Use of this airport for commercial purposes would 
relive much of Logan's overcrowding. The same holds true 
for Homestead Air Force Base. The base is in a ideal 
location to be used for local flights and other aviation 
uses. 

Overall future of airport pavement construction is not 
a bleak as other construction areas. Construction of whole 
new airports is unlikely but repairing and expanding and 
modifying existing facilities will likely continue at a 
reasonable pace. Owners will likely use more sophisticated 
managerial tools reduce impact to airport operations and 
improve communications with the contractor during 
construction. Each competing contractor will have to use 
all of the innovations available to maintain there 
competitiveness and receive a part of the pavement 
construction work load. 

68 



BIBLIOGRAPHY 



1. Merwin, Donald, "Around our airports, Billions in 
Commercial Growth", Highway & Heavy Construction . 
July 1990, p. 22 

2. "Busy Airport Rehabilitates Runway to Increase service 
Life", Public Works . January, 1988, p. 44 

3. Herbsmen, Zohar and Ellis, Ralph, "Multiparameter 
Bidding System — Innovation in Contract 
Administration", Journal of Construction and 
Management . March 1992, p. 142 

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