"There are well over 100,000 miles of concrete pavements existing today on our United States highway system. The development of these pavements during the first half of this century has been a process of learning from construction applications and mistakes. However, the unexpected increase in traffic load has brought highway designers to experiment with relatively new types and designs of concrete pavement construction.
Some designers, in an effort to reduce temperature warping stresses, have used short slabs 10 to 15 feet in length, generally unreinforced. Another type of construction is the definitely jointed slabs, the slabs being from 20 to 100 feet long with steel reinforcement of some kind and a load transferring device at the joints. Experiments and construction with continuously reinforced pavements, employing very long slabs, in attempts to eliminate the problems incidental to joint construction and performance, have been going on in recent years.
Unfortunately the lessons to be gained from a new type of pavement construction generally takes a long time. It has been estimated that five to ten years are needed for a pavement to attain material adjustments, conditions of sub grade support, and stresses characteristic of a mature pavement. Therefore, the relative merits or disadvantages to any of the mentioned types of pavements remain to be determined with time. One factor is known to be common to all types of pavements, that is the development of cracks, although very minute in some types.
Along with these different types of construction is the trend to thicker pavements. Thus the pavement is becoming more rigid on a sub-base that is flexible. Considerable investigation has been expended in an effort to arrive at a rigid sub-base which would have properties inherent to that of the concrete. Moisture entering the sub-base and eventually causing a ''void" or area with no support to the pavement has been a problem for rigid pavements.
In considering these problems confronting the highway engineer it is conceivable that a prestressed concrete pavement may offer some possible answers.
It is known that in order for the prestressing process to be economical the prestress load must be transferred to the concrete at very early ages, therefore, an economically high early strength without detriment to other properties need be obtained. This has led to this investigation into the early age properties of regular Type I non-reinforced concrete at an elevated temperature.
It is hoped the results obtained will further advance our knowledge of the properties of concrete and eventually lead to the development of an economical, long life pavement which is the ultimate goal of all highway engineers"--Introduction, page 1.
Carlton, E. W.
Civil, Architectural and Environmental Engineering
M.S. in Civil Engineering
Missouri School of Mines and Metallurgy
v, 116 pages
© 1957 Karl H. Dunn, All rights reserved.
Thesis - Open Access
Library of Congress Subject Headings
Concrete -- Cracking -- Testing
Concrete -- Additives -- Testing
Strains and stresses -- Mathematical models
Print OCLC #
Electronic OCLC #
Link to Catalog Record
Dunn, Karl H., "Physical properties of concrete at early ages" (1957). Masters Theses. 4091.