Study on the Effect of Amorphous Silica from Waste Granite Powder on the Strength Development of Cement-Treated Clay for Soft Ground Improvement

Granite powder (stone powder), a waste product generated from stone quarries, is increasingly being reused in cement-treated clays. The particle size of powders affects the cement-clay reaction by either increasing or reducing unconfined compressive strength (UCS). This study investigated this phenomenon separating same batch at quarry into five sizes (A, B, C, D and E: 106–75 µm, 40–75 20–40 <20 µm 106–<1 respectively). Flow value, fall cone, UCS thermogravimetry-differential thermal analysis (TG-DTA), X-ray fluorescence, electrical conductivity NaOH digestion tests were conducted. It was discovered that had an amorphization rate up to 1.45% (14.5 mg/g amorphous silica); hence, it pozzolanic. However, amorphousness varied with material order > E C B A, which translated variation order. Stone played two roles development, i.e., nucleation cementitious products Ca(OH)2 increase higher than control sample. Linear regression equations determined minimum concentration silica for increment as 9.4 mg/g.