Developing green cement paste using binary and ternary cementitious blends of low pozzolanic sewage sludge ash and colloidal nanosilica (short-term properties)

Abstract

This study investigates the effect of small dosages of nanosilica (0.5 and 1.5% of the total binder) on physical, mechanical, durability, and microstructural properties of green cement paste containing sewage sludge ash (SSA) with low pozzolanic activity. Experimental results revealed that hardened performances of cement pastes were reduced significantly by incorporating SSA particles at higher replacement ratios (> 10%), whereas mechanical and durability properties of cement paste specimens were improved by the addition of nanosilica both at early and moderate ages. According to the microstructural investigation, the activity of SSA particles in the presence of nanosilica can be improved.