Feasible use of Cement Treated Crushed Waste Clay Brick Aggregate as RoadSubBase

摘要

This Laboratory tests were conducted to investigate the possibility of using crushed waste clay brick as aggregates in cement treated materials for sub-base. In this study, the aggregate properties were evaluated firstly and crushed brick was added into mixtures to replace natural aggregate. Five kinds of aggregates which contained 0%, 25%, 50%, 75% and 100% crushed bricks were treated by 5% cement respectively and the maximum dry density (MDD) and the optimum moisture content (OMC) of the mixtures were confirmed. Then Specimens were prepared and 7d, 28d, 90d unconfined compressivc strengths (UCS), 28d, 90d tensile splitting strengths and thermal shrinkage coefficients as well as frost resistance performance were tested. The results indicated that cement treated aggregates which contains crushed waste brick had a lower MUD and a higher OMC. This was mainlyattributed to the lower density and higher water rate of crushed brick compared to those of natural aggregate. Moreover, the replacement of natural aggregate by crushed brick further decreased the UCS, tensile splitting strength and frost resistance index of cement treated aggregate and increased the thermal shrinkage coefficient of the cement treated aggregate slightly. Although the use of crushed waste bricks affected the mechanical properties of cement treated aggregate, the UCSs of all mixtures in this study were greater than 1.5 Mpa, which is a minimum UCS requirements of cement treated aggregate sub-base material for asphalt pavement design specifications in China. The cement treated aggregate which contains crushed brick should be used cautiously in the frozen region due to its poor frost resistance performance.