Laboratory-Scale Investigation on Band Gradations of Aggregate for Concrete

摘要

Aggregate gradations have significant effects on concrete properties because approximately 70％ of the volume of concrete is occupied by aggregates. Various researchers, specifications, and codes have suggested different types of aggregate gradations for concrete mixtures. This paper presents a comparative analysis among available aggregate gradation methodologies and analyzes different aspects of two proposed band gradations through laboratory experiments. The overall research was conducted in two stages. In the first stage, concrete mixes were prepared using different aggregate gradation methodologies to find out the comparatively better aggregate gradation methodology in terms of concrete properties. Analyzing the results of this phase, the newly proposed 5-10-14-18 and 5-10-18-22 band gradations were found to give better concrete properties compared to other aggregate gradation methodologies with respect to concrete workability and compressive strength. The objective of the next stage was to assess different practical and theoretical aspects of these selected band gradations. In addition, a brief analysis is given on the possible application of the fineness modulus (FM) and fine aggregate to total aggregate (FA/TA) ratio chart to obtain an optimum aggregate gradation.