Effects of silica fume and zeolite on the durability of engineered cementitious composite containing limestone powder and blast furnace slag in a magnesium sulphate medium

Abstract

Engineered cementitious composite (ECC) is a highly ductile high-performance fibre-reinforced cementitious composite whose design, mixing ratios and other important parameters can be optimised using the theory of micromechanics. This study investigated the effects of different quantities of silica fume and zeolite on the mechanical properties and durability of ECC specimens containing lime stone powder and blast furnace slag when treated in the 5% magnesium sulphate solution at 28, 150, 180 and 210 days of age. The results obtained showed that the compression strengths in lab environment were enhanced up to 25% at the age of 150 days by increasing the silica fume content of the ECC, whereas the modulus of rupture (MOR) and mid-span deflection (MSD) were decreased in all the specimens tested. Meanwhile, a 17% increment in blast furnace slag content was observed to enhance both MSD and MOR at all ages, e.g. it causes 23% increase in MSD and 9% increase in MOR at the age of 28 days. In addition, a 46% increase in lime stone powder content was found to increase compressive strength but to reduce MOR by 7% and 8% at the age of 28 days, respectively.