Performance Investigation of Diatomite Modified Asphalt Mixtures for Different Diatomite Ratios and Grinding Sizes

Abstract

Modification of asphalt mixtures has become almost mandatory today due to increased stresses in pavements, shortening of load cycle times, and decreases in binder quality. For this reason, many additives can be added to bitumen or asphalt mixture. Industrial material wastes can also be among these additives. When diatomite material is used as a performance enhancer in asphalt mixtures, it significantly improves the main performance indicators of the asphalt mixture. However, low temperature cracking of diatomite-modified asphalt mixtures is still controversial in the literature. This study evaluated the asphalt mixture in terms of low-temperature cracking, water damage, and rutting, depending on the diatomite grinding size (gradation) and addition ratio. Three different sizes of diatomite additives (106, 212 and 300-micron maximum diameter) were used at three addition ratios (5, 10 and 15% by weight of bitumen). According to the test results, it was seen that the mechanical properties of asphalt mixtures were significantly affected by the addition ratios and diatomite sizes, and the use of 300-micron maximum diameter diatomite at the rate of 10% and 15% was more effective. However, according to the BBR test results, the use of diatomite additives with a maximum size of 106 µm at 5% increased the low temperature cracking resistance, slightly.