ASSESSMENT OF THE CURRENT LIMITATION ON THE FLAK AGGREGATE CONTENT OF ASPHALT CONCRETE MIX

• Main Author: Bactiar, Zulkarnain
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/3025
• Institution: Institut Teknologi Bandung

An excessive amount of flaky aggregate in a bituminous mixture is generally considered to be detrimental to its performance and a limit is normally placed on the maximum permitted amount. The Bina Marga Standard requires the flaky aggregate content not to exceed 25%. However in the field it is not always possible to meet this requirement. <br /> The research programme described in this thesis was designed to evaluate the influence of flaky aggregate content on the properties of aggregate mixture and of bituminous mixtures designed by the Marshall method and to assess the Bina Marga Standard. Flaky aggregate contents of 0%, 15%, 25% and 35% were investigated; these contents were achieved by adding flaky aggregate in the required amounts to aggregate retained on the 19.1 mm, 12.7 mm, and 9.52 mm sieves. Aggregate mixtures containing flaky aggregate in the amounts investigated were found to have satisfactory strength, toughness and hardness as indicated by such tests as aggregate crushing value, aggregate impact value, ten percent fines value and Los Angeles Abrasion value; quality, however, reduces with increase in the flaky aggregate content. Bituminous mixtures containing up to 35% flaky aggregate satisfied Bina Marga design criteria. The mixtures had satisfactory resistance to water damage as indicated by Index of Retained Stability. The major influence of flaky aggregate content became apparent in resistance to deformation at high temperature; resistance reduced significantly as the flaky aggregate content increased. The data on resistance to permanent deformation suggest that the current Bina Marga maximum of 25% may be too high. However, a more comprehensive test programme involving measurements of workability, indirect tensile strength and resilient modulus is needed before definite conclusions can be drawn .