Microscopical and mechanical evaluation of the durability of SiO2aggregates

Abstract

The durability of SiO 2 compounds is closely related to its structural properties. In this work three natural siliceous aggregates (called G1, G2 and G3) are studied. Improvement of the durability of the starting material leads to a significant energy savings by extending the lifetime of structures. The chemical composition of the three natural aggregates shows that G1 and G2 have almost the same chemical composition (SiO 2 ) and G3 is different and contains SiO 2 quartz type and calcite as major components (SiO 2 , calcite and dolomite). X-ray diffraction (XRD) shows that natural aggregates G1 is more crystallized than G2 and G3. After alkali silica reaction (ASR) process, the reactivity of G3 aggregate seems to be higher than the G1 and G2 aggregates. The mechanical results show the slight difference between mortar containing G1 (M_G1) and that containing G2 (M_G2). Their compressive strength is 10% less than that of reference (M_SS). As it is more reactive, G3 seems improving the compressive strength of M_G3, compared to M_G1 and M_G2.