From the above table, it will be noted that aggregates constitute the largest dollar volume of materials used-30 percent; steel accounts for 25 percent; cement and bitumen, each 10 percent; petroleum products, 8 percent; concrete pipe, 4 percent; and all remaining material items, 13 percent.

Authority to conduct research and development

The Bureau of Public Roads has for many years encouraged the use of proven new materials and new processes and designs that will put conventional materials to new uses in the Federal-aid highway programs. The Congress authorized such activities under title 23, United States Code, section 307, as follows:

Section 307. Research and Planning.

(a) The Secretary is authorized in his discretion to engage in research on all phases of highway construction, modernization, development, design, maintenance, safety, financing, and traffic conditions, including the effect thereon of State laws and is authorized to test, develop, or assist in the testing and developing of any material, invention, patented article, or process. The Secretary may publish the results of such research. The Secretary may carry out the authority granted hereby, either independently or in cooperation with any other branch of the Government, State agency, authority, association, institution, corporation (profit or nonprofit), or any other organization, or person.

These functions have been delegated to the Federal Highway Administrator.

Bureau's activities in the materials field

The Bureau of Public Roads is engaged in many activities in an effort to carry out this responsibility for continuously seeking_improvements which will benefit the highway program. Many of these activities have an impact on the use of materials for highways.

For example, the Bureau is cooperating closely with the equipment industry which is currently spending $100 million annually to develop improved machines. While not all of this work is done on equipment used in highway construction, the highway industry does benefit either directly or indirectly from the expenditure of most of these funds. The improved machines, which have resulted from this effort, are helping to keep down the cost of highways. In addition they are enabling us to construct, maintain, and operate highways more efficiently and are assuring the highest quality in the roads we build. A listing of total bids by States discloses that contractors' bids on Federal-aid work for the calendar year 1961 were $254 million below the engineers' estimate of $3,020 million.

But these benefits will not fully accrue to the highway program until the new equipment of proven merit is used for roadwork. Often these benefits are delayed by needless restrictions in specifications. The productive capacity of modern material-processing equipment, such as mixers and pavers, is limited sometimes by mixing time requirements that are in excess of what research has shown to be necessary for best quality. This adds to the cost of processing, reduces the incentive for contractors to buy more productive, more efficient machines, and discourages the manufacturers from further improving their products.

The Bureau is making a considerable effort to eliminate such unnecessary and detrimental restrictions from highwav specifications. This is accomplished in a number of ways. Some of these ways are

(1) Direct contact with State highway officials.

(2) American Association of State Highway Officials' committees.

(3) Highway Research Board committees.

(4) Joint committees of the American Association of State Highway Officials and the American Road Builders' Association. (5) Joint committees of the American Association of State Highway Officials and Associated General Contractors, Inc.

(6) Other industry associations such as the Asphalt Institute, Portland Cement Association, Construction Industry Manufacturers' Association, National Bituminous Concrete Association, National Crushed Stone Association, and many others.

Through these channels, the Bureau is encouraging the development of further improvements in equipment and their use in the highway program. This effort has a direct impact upon the use of materials for highways because all operations are highly mechanized. The use of improved machines means greater efficiency, economy, and quality in handling, processing, and placing materials in the construction, maintenance, and operation of highways.

Through many of the same channels the Bureau is seeking greater uniformity in highway specifications by encouraging wider use of approved and recommended standards including those for materials as well as their use. This should foster economies by reducing suppliers' overhead costs, it should reduce errors due to misunderstandings, and should promote better quality in the finished product.

The Bureau is constantly evaluating the merits of new materials and new uses or new processes for conventional materials. There are several ways that these evaluations are made.

Sometimes they are made in the laboratory facilities of the Bureau under the Physical Research Division in the Office of Research. In other instances research projects are set up in which the Bureau participates jointly with State highway departments, universities, industry, and others. A third way is to use the experimental project program. Under this program new materials or processes are incorporated or used experimentally on regular Federal-aid highway projects.

Through these and other means the Bureau is making a continuous effort to take advantage of new materials, methods, processes, and equipment for highways. Once the evaluations show that the new development has merit, its use is encouraged, and it is accepted when included in specifications for use on Federal-aid work. The market for these new products thereby encourages industry toward still further improvements.

New methods in exploration for materials

The deposits of natural aggregates are diminishing with increased public works activities. The Bureau of Public Roads, in cooperation with State highway departments and other agencies, has developed techniques for the exploration and general location of aggregate deposits through aerial surveys and photogrammetry. Bureau of Public Roads engineers have promoted the use of these techniques and trained highway department engineers in photogrammetry. By this aerial survey method, characteristic soil deposits and drainage conditions can be studied readily to facilitate the selection of a favorable location for the highway.

The Physical Research Division of the Bureau of Public Roads has also developed an instrument for identifying soils in place by measuring the electrical resistivity of the subsurface layers. Once the general topographical and geological characteristics of an area are determined from an aerial survey, the electrical resistivity instrument may be used for subsurface exploration to locate rock and aggregate deposits suitable for highway construction. Entire States are being surveyed by photogrammetry and related methods to locate aggregate reserves for the road program. A material survey was completed in 1959 for an interstate route in North Dakota. Materials surveys also were completed in conjunction with engineering soil surveys in New Jersey and Rhode Island. Similar surveys are underway in 14 other States and Puerto Rico. As a special research project, color aerial photography was used by the Bureau of Public Roads in a materials survey in Yellowstone National Park in 1961. The objective is to more positively identify the characteristics of ground deposits.

Currently, a system of image processing is under development in which shades of gray are optically scanned from aerial photographic pairs. Each shade has a code number. The digital information, taken from the photographs, is analyzed on a computer for speedier identification of ground characteristics. This development holds promise for expediting the inventory of natural resources.

An equipment manufacturer has developed a new application for a highly portable seismograph for subsurface exploration. It may change the method and lower the cost of exploration. Under former practices when a subsurface ledge was encountered dynamite was used, even near populated areas. Now a seismograph is used to identify the subsurface rock and its condition by measuring the time it takes sound waves to travel through it. If the material is identified as of a softer nature that can be ripped, newer and more powerful tractors equipped with more durable steel pointed rippers are utilized. Formerly, this equipment had to be taken out on the project to determine whether or not subsurface strata could be ripped. With the seismograph technique, the benefits from fast, economical ripping can be used more frequently thus holding down excavation costs. New methods in highway design for economic utilization of materials

Beginning in 1955, engineers in the Division of Development in cooperation with State highway departments started an intensive evaluation of the electronic computer. They found it had great potential as a means of increasing highway engineering productivity by relieving engineers of repetitive, time-consuming, routine calculations that were being performed manually. This was at a time when additional engineering productivity was urgently needed to get the expanding program underway and keep it on schedule.

Application of electronic computers.-The first problem was to develop programs for the solution of highway engineering problems on this computer. In cooperation with the State highway departments, consulting engineers, universities, and others, the Bureau established a library of computer programs. These were contributed by the participants, including the Bureau. This joint effort saved duplication and greatly expedited the integration of the benefits of the computer into the highway program.

Forty-eight State highway departments and the Bureau of Public Roads now have electronic computers and the remaining highway departments rent computer time commercially. The library established by the Bureau has grown, too. There are now about 500 programs in the electronic computer library relating to many highway functions.

Numerous electronic computer programs are being utilized in the determination of the most economical movement and utilization of materials in embankment construction. On bridge designs, computations can now be made over 100 times as fast as by former methods. It permits the consideration of more alternate designs for structures; it makes feasible a more thorough study of the type of materials to be used in the bridge; and it makes possible a more thorough check of the stresses the materials will carry.

The masses of data involved in forecasting and assigning future traffic to systems of existing and proposed roads and streets can be done far more precisely than ever before. The resulting highway geometrics, including materials comprising base and surfaces of pavements and engineers' estimates for bidding, can be obtained readily. The modern electronic computer technique is being applied to the selection of designs and materials in many areas of highway operations. For example, a computer program is being developed for hydraulic analyses in the design of circular culverts, pipe arch culverts, and box culverts. The program will provide for the quick computation of the size, headwater, and velocity of each type of culvert for given design conditions. This permits the more precise selection of the most economical design and materials from the computed data for the condition involved.

The electronic computer and other new engineering tools have had a tremendous impact upon the highway program. They have been a major factor in increasing engineering productivity. As a result, highway departments have been able to accelerate the construction rate to keep the program on schedule. They are saving millions of dollars annually because with them the highway program is being carried out more efficiently, more economically, and with improved quality.

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The high degree of automation in highway engineering today made possible by these new tools has had other far-reaching effects. cause automation enables us to bring more work to the construction stage each year, the markets for labor, equipment, services, and materials have been stimulated, thereby adding to the strength of

our economy.

For example, a 1959 study by the Bureau of Public Roads, illustrated by map as Exhibit M, shows an approximation of the widespread economic impact resulting from labor requirements generated in terms of material and equipment production for highway construction. Projects in other locations would generate different labor hour distribution patterns depending on transportation distances and other

factors.

High speed data transmission. Furthermore, with the increasing use of computers and allied equipment for automatic data storage and processing, there has been generated a growing requirement for high speed data transmission between field offices and computer centers. This requirement has increased the demand for existing wire line

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communication services such as telephone, telegraph, teletype, and facsimile. It has also encouraged the development of new and improved facilities for high speed data transmission. Some of these new facilities are now available. Some use radio, including microwave, frequencies instead of wire lines. The speed of transmission by teletype, by facsimile, and by other new facilities has been greatly increased. Here again the highway program is adding to the market for new products and for increased use of new and conventional materials.

New test methods for quality control of materials

In order to assure the proper selection and processing of materials in-place, the Bureau of Public Roads and the State highway departments have been encouraging the application of modern technical advancement in faster testing methods. Radioactive materials are being used in devices to test the moisture and density of embankments in determining the degree of each compaction contractors have secured for pavement foundations. In the past it took from 1 to 3 hours to secure field samples, transport them to a laboratory, perform the tests, and inform the contractor that he has or has not accomplished the requirements of the specifications.

Nuclear moisture-density gages.-Now, a small portable device, using back-scattering nuclear radiation principles, can take both moisture and density readings on the jobsite within a fraction of the time required by conventional methods. This saves the contractor excessive rolling time by immediately advising him when the required compaction has been reached. The State and Federal Governments also benefit through the ability to take more readings and secure better quality control. The Bureau of Public Roads, together with Colorado, North Carolina, Ohio, and Wyoming, has made notable advancements in this area.

Many other applications which use nuclear energy are being investigated for possible highway usage. It can be used to determine the soundness of wood in timber structures. Industry has already developed and successfully applied nuclear testing devices for quality control in measuring the thickness of various materials and coatings. Its feasibility is being studied for the measurement of pavement thickness. Radioisotopes are being used to test the soundness of metals. Nuclear energy applications already in use by industry are being studied to determine if they can be adapted to give us a better check on when certain highway materials are properly mixed. The feasibility of sonic and ultrasonic instrumentation for measuring pavement thickness is also being explored.

New scientific developments are taking place very rapidly these days. The Bureau and the State highway departments are evaluating many of these which appear to have application in the highway program. Already some are in use as methods of nondestructive testing for quality control. Fast infrared spectrophotometry tests can now be made in minutes, of the composition of paints, weed eradicators, concrete admixtures, and other materials. Such tests formerly required at least a day. Infrared energy and X-rays are also being used with considerable success for checking the quality of welds on highway bridges.