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Title: Research Needs: General Materials, Mineral Aggregates, General Maintenance
Accession Number: 01837366
Record Type: Monograph
Abstract: This circular presents 19 research problem statements in the fields of general materials, mineral aggregates, and general maintenance from the General Materials Division of the Department of Materials and Construction, Highway Research Board. In the area of aggregates, two of the proposals reflect the current concern over speed and accuracy of construction control. The proposed use of statistical specifications requires a new look at the sampling of aggregate since this procedure may have more effect on the spread of test results than has the material itself. As sources of good aggregate become depleted and long range planning of available sources become of importance, it is probable that knowledge of the effect of environment on the properties of in-place rock and gravel could be desirable. A Weather Severity Index may be useful to do this. In the area of sealing joints in bridges and roadway pavements, it would seem that this apparently simple problem should be solved. Unfortunately, it is not. Proposals have been made to study the adhesion and adhesives for joint seals, practical joint seal design methods, and more effective crack sealing in pavements. In another area, that of highway culverts and conduits, the overall refinement of design of culvert pipes as well as the construction of higher fills has required the highway engineer to extrapolate experience and empirical formulas based on conditions that were far less demanding than at present. This has led to six proposals in this area covering non-symmetrical surface loads over buried flexible culverts, measurements of settlement ratios of buried rigid conduits, soil pressure on bored-into-place culverts, relative influence of yield point strength of material and stiffness of culvert walls in the support of soil pressure by buried flexible culverts, use of deformed mesh in reinforced concrete culvert pipe, and relationship between ultimate three-edged bearing loads and ultimate field loads for RC pipe. The development of new materials for thin surface coatings has opened up a completely new area for worthwhile development. Most of such surfacings contain epoxy resins which have now been developed to the point where the highway engineer can use them economically. Five projects have been recommended in this area covering the following specific needs: Low or moderate cost, thin surface coatings; determination of effects of elements on epoxy resin compounds; epoxy resin-aggregate resurfacing; delamination of epoxy surfacings from concrete; and physical properties of epoxy resins. In addition to the use of the epoxy resins in thin surface coatings, its use as an additive in concrete could produce a concrete with entirely new properties and design potential. To do so requires more knowledge so it is proposed to determine the basic properties of such a material. The committee on metals is especially active in the field of welding metallurgy. It is recommended that the behavior of all forms of welded beams, girders and trusses under both static and fatigue loadings be explored in depth.
Supplemental Notes: Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
Language: English
Pagination: 21p
Publication Date: 1966-10
Serial: Media Type: Digital/other
TRT Terms: Subject Areas: Highways; Materials; Research
Files: TRIS, TRB
Created Date: May 18 2021 3:37PM
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