Mechanical properties of concrete containing 100% treated coarse recycled concrete aggregate

An environmental friendly method for enhancing mechanical properties of recycled aggregate concrete (RAC) is proposed by using sodium silicate and silica fume. The proposed method, applied to 100% coarse recycled concrete aggregate compared to untreated RAC, can improve compressive strength up to 33-50%, splitting tensile strength 33-41%, and elastic modulus 15.5-42.5%. Tests revealed that the direct tensile strength of RAC and natural aggregate concrete (NAC) were notably lower than the splitting tensile strength, but at 7 days, these values of treated RAC were higher than the splitting tensile strength. From the experimental data, the compressive strength of the treated RAC can be estimated at any age. Besides, the relationships between mechanical properties of treated RAC which were established were significantly different from those of NAC and untreated RAC in previous studies.