Measuring the Specific Gravities of Fine Aggregates: An Automated Procedure

Evaluating the use of the new automated SSDetect to determine fine aggregate specific gravities in Michigan was the research objective described in this paper. Currently, fine aggregate specific gravities in Michigan are determined through the use of the American Association of State Highway and Transportation Officials (AASHTO) Standard, AASHTO T-84, "Standard Method of Test for Specific Gravity and Absorption of Fine Aggregate." A standard frustum cone and tamping rod are utilized in the basic test procedure to find fine aggregate saturated-surface-dry (SSD) state after the fine aggregate has been soaked in water for 15 hours. Because they do not readily slump, the AASHTO T-84 is problematic with angular and rough textured fine aggregates, in addition being time consuming. To accurately and efficiently find specific gravities through the use of the scientific laws of infra-red light ray reflection, the new SSDetect is proposed as a viable alternative. Research results include that for specific gravity measurement, there is statistical similarity between the AASHTO T-84 and SSDetect.