ENHANCEMENT OF RECYCLED AGGREGATE CONCRETE PROPERTIES BY A NEW TREATMENT METHOD

Abstract

Recently, decreasing natural sources of aggregate accompanied by increasing large quantitiesof construction and demolition waste (CDW) cause challenges for environment and construction industry. Asignificant solution for this is to recycle CDW as a new aggregate source for concrete. However, usingrecycled concrete aggregate (RCA) in concrete involves various obstacles and controversial issues incontrolling the quality of recycled aggregate concrete (RAC). This study is an effort to improve the quality ofRAC containing 100% coarse RCA by using pozzolanic and sodium silicate solution as new treatmentsolutions. This study examined performance abilities of RAC after being treated with new treatment solutionsand a new mixing procedure. The mechanical properties of RAC were evaluated based on testing of concreteunder various conditions. The significant results indicated that sodium silicate combined with pozzolanicmaterials can improve mechanical properties of RAC containing 100% coarse RCA. At 20% concentration ofsodium silicate and silica fume, the compressive strength of RAC could improve up to 36%. Achievements ofthis approach demonstrated its effectiveness in enhancing the strength of RAC, which is potentially appliedto treating RCA for concrete in the future.