Study On The Properties And Application Of Sand Asphalt Mixture

Research group, combined with the research situation at home and abroad, use the sand type modified asphalt mixture to control the cracks of semi-rigid base pavement reflection. The main research work on the asphalt pavement mineral stone selection, domestic road workers mostly use the basalt in practical engineering, which with the uneven distribution, more and more expensive price and limited reserves; considering the engineering cost and future technology promotion less affected by the territorial restriction, research group decide to choose the limestone which has the low price, easy acquisition and the big reserves; quarry processes smash into 3-6 coarse aggregate, fine aggregate and filler 0-3 three aggregate as mineral stone of this project for the study of geographical restrictions; and through the indoor experiment obtained the each sieve size quality passing percentage and primary technical properties index of the three aggregate; the results show that limestone aggregates completely satisfy sand type modified asphalt mixture to prevent reflection cracks of semi-rigid base pavement. In the selection of modified asphalt, subject group considering the characteristic that prevent reflection crack of semi rigid base pavement was not laying stress absorption layer on the modified asphalt demanding compared with the old cement pavement, we fabricated rubber powder in 60 tire 90# petroleum asphalt and modified asphalt mix 20%, aimed at the 90# petroleum asphalt, crumb rubber modified asphalt and SBS modified asphalt product Esso asphalt, three index of main technical properties were measured; the results showed that the properties of crumb rubber modified asphalt and Esso SBS modified asphalt product can meet the sand type modified asphalt mixture in preventing reflection cracks of semi-rigid base pavement on modified asphalt, but with a view to the crumb rubber modified asphalt mixing rubber more than SBS, technical properties of modified asphalt product not much difference point and the production of crumb rubber modified asphalt also need to invest in construction of asphalt production equipment, raw materials selection, easy to get the final group project relatively cheap price and technical properties the higher the Esso SBS modified asphalt product as sand type modified asphalt mixture.Through the analysis of the domestic existing asphalt mixture design method combined with sand type modified asphalt mixture of fine mineral stone, ore accounted for significant (2%～6%), low void ratio(1%～2.5%) and the large asphalt aggregate ratio (about 9%) of the actual characteristics, with the spirit that void gradation curve should meet the requirements that the mineral aggregate as far as possible from the maximum density curve to determine the amount of each gear far with aggregate in the mixture, determined the optimum asphalt content; research group used Marshall test which is current widely used and experienced to determine the mix design method, and the calculation formula of the theoretical maximum relative density of mixture adopted the calculate standard recommended. Ultimately determine the aggregate composition of 3-6:0-3,powder as 28:69:3,optimal asphalt aggregate ratio is 9.2%.After the sand type modified asphalt mixture with the Composition of mineral aggregate gradation and determination of optimal asphalt content ratio design, research group verified the modified asphalt mixture of sand type in different pavement performance and build the test road for long-term observation of reflection crack prevention effect.