Investigating the Effect of Technical Characteristics of Aggregate Materials on the Compaction of the Base Layer by Response Surface Method

One of the most fundamental issues in road construction is to increase the density and strength of the layers of stone materials to the desired level;. For this purpose, the different layers of the pavement should be compacted to an acceptable extent by means of asphalt rollers. On the other hand, the performance of the pavement aggregate layers, which is highly effective on the performance of the entire pavement, is influenced by their compaction. Therefore, it is very important to investigate the factors affecting the field compaction of the pavement layers including the base layer. As a result, this research aims to examine the effect of the characteristics of the base layer materials on their relative compaction using the response surface methodology. For this purpose, the characteristics of stone materials including moisture content, dry density, optimal moisture content, the thickness of the base layer, maximum ambient temperature, minimum ambient temperature, the plasticity index, the sand equivalent value, and uniformity coefficient were extracted from the laboratory sheets related to Dahaghan, Kohpayeh and Shahrekord projects and then analyzed using Design Expert and SPSS software. The results show that the relative compaction has an inverse relationship with laboratory dry density, layer thickness, maximum temperature, the plasticity index and the sand equivalent value. Furthermore, we show that there exists a direct relationship between relative compaction and the minimum temperature and the uniformity coefficient.