SPECIFIC GRAVITY AND ABSORPTION TESTS OF COARSE AND FINE AGGREGATES FOR USE IN THE DESIGN OF ASPHALT CONCRETE MIXTURES.

Author(s):  
Irving Kett
Author(s):  
Chun-Yi Kuo ◽  
Reed B. Freeman

The performance of asphalt concrete mixtures is influenced by the properties of the included aggregates, such as grading, shape (angularity and elongation), and texture (roughness). Complete and accurate quantification of aggregate properties is essential for understanding their influence on asphalt concrete and for selecting aggregates to produce high-quality paving mixtures. Recent developments in the use of digital image analysis techniques for quantifying aggregate morphological characteristics in asphalt concrete are summarized. Image morphological characteristics were used to quantify flatness and elongation of coarse aggregates, to estimate the proportion of natural sand in fine aggregates, and to correlate aggregate characteristics with engineering properties of asphalt concrete mixtures. Image analysis of sections also revealed information about the grading, shape, and orientation of coarse aggregates in a mixture. An overview is presented of the broad range of useful pavement engineering applications of this relatively new approach for evaluating aggregate characteristics.


2017 ◽  
Vol 79 (2) ◽  
Author(s):  
Gito Sugiyanto

Highways are important transportation infrastructures that influence economy, culture, and security. Most of the highways in Indonesia are flexible pavement that use asphalt as a binder. The use of scrapped tire rubber as a partial replacement of fine aggregates is based on the limited available natural aggregate in nature. Utilization of scrapped tire rubber as a fine aggregate is one of the alternatives for reducing environmental pollution and supporting Clean Development Mechanism program. The aim of this study is to analyze the Marshall test characteristics of asphalt concrete (AC) mixture that use scrapped tire rubber as a partial substitute of fine aggregate and comparing with a standard mixture. Laboratory tests are performed on three different types of mixtures as follows the mix without scrapped tire rubber, mix containing 50%, and 100% substitution of aggregate at fraction of No.50 with scrapped tire rubber. The test, it show that optimum asphalt content for ACStandard mixture is 6.76%, while ACScrapped-tire 50% mixture is 7.04% and ACScrapped-tire 100% mixture is 6.25%. The use of scrapped tire rubber in asphalt concrete mixtures can improve the resistance to permanent deformation and resistance to water. The use of scrapped tire rubber is acceptable as a partial replacement of aggregate in asphalt concrete mixtures.  


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