The dynamics of changes in asphalt concrete mixture composition in storage, transportation and laying

Abstract

The article analyses the rate of transformation of major properties of asphalt concrete mixture (ACM) from the time of its manufacture to placing on the road as well as the problem of testing and evaluation of its composition. The produced ACM is unloaded in batches from the mixing plant and transported by a skip hoist to the mixed material silo, then to the truck body and, finally, to the site. The transported ACM is poured in batches to the skip of the hoist and is continuously supplied by a transporter to the worm distributor, where a layer of the required thickness and cross-fall is spread and compacted by vibration. Sixty five separate samples of 0/22A grade ACM were taken at all six stages of the process, and their composition (grading and bitumen content), bitumen characteristics and physical-mechanical indices of Marshall samples were identified. Having processed the data of tests according to mathematical statistics methods, the trends of ACM properties transformation were identified from the obtained data and the causes of the changes were analysed. Practical recommendations allowing the differentiation of ACM characteristics at different stages of its use, based on sample testing, are given. The data of the present research may be used for upgrading quality control methods of asphalt concrete pavement. They may also be applied in developing and upgrading the Guidelines for Construction and Lithuanian Standards.