The 14 papers in this volume address the testing or performance of aggregate materials in highway applications. The initial five papers were presented at the TRB 75th Annual Meeting in a session titled “Aggregate Tests Related to Performance” organized by Stephen W. Forster of FHWA. The remaining nine papers are related to materials tests. The performance of coarse aggregate in concrete pavements is covered by Koubaa and Snyder, who address the freeze-thaw resistance of carbonate aggregate, and by Choubane et al., who discuss the effect of coarse aggregate on the elastic moduli of concrete. Two groups of researchers address the performance of aggregate in bases: Heydinger et al. examine the effect of gradation on resilient modulus, and Garg and Thompson report the results of a study in which recycled asphalt pavement was incorporated as the base material. On the subject of the performance of aggregates in asphalt pavements, Ahlrich reports the influence of aggregate on the performance of heavy-duty hot-mix asphalt pavements, Abdul-Malak et al. discuss those aggregate characteristics that govern the performance of seal coats, and Speir and Witczak outline their findings on the use of shredded rubber tires in pavements. Won and Fu consider laboratory procedures for the evaluation of aggregate polish susceptibility in relation to use in a surface course. Nazarian et al. propose a resilient modulus testing procedure that includes modifications to the AASHTO standard method. Ping et al. describe a laboratory study to evaluate pavement subgrade soils at 20 test sites using the Florida limerock bearing ratio test, which is a modification of the California bearing ratio test. Thevanayagam et al. present results of laboratory tests showing that fines content plays an important role in the steady-state strength of sands classified as clean, silty, or sandy silts. Lekarp et al. examine the permanent deformation of different types of unbound aggregates under repeated loading. Al-Sanad and Ismael report laboratory and field test results on the effect of aging on the strength and compressibility of calcareous sands. Radovsky and Murashina present a mechanistic model of a subgrade to predict its performance during compaction by rollers as a function of contact pressure and strength characteristics of soils. (Author/publisher)
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