Chemical Analysis of Silica Fume Infused Self Healing Concrete

Abstract

Self healing technique using mineral and chemical admixtures are gaining momentum nowadays. Admixtures like silica fume, marble dust, fly ash, ground granulated blast furnace slag, limestone powder are being experimented nowadays as self healing agents. In this experimental examination, silica fume has been used as a healing agent (12.5% replacement). Cracks were induced and the specimens were subjected to continuous water exposure for 28 days. After 28 days, the specimens were tested for healing effect and the healing products were chemically analyzed by means of FESEM analysis, EDAX, thin section test and XRD analysis. From FESEM and EDAX analysis, for silica fume mix, portlandite formation was evident. Thin section analysis showed the morphology of anorthite feldspar. XRD analysis showed that excess silica content in silica fume actively involved in faster healing process resulting in the formation of calcite, calcium hydroxide and calcium carbonate. All the test results indicated that self healing property can be achieved using silica fume as mineral admixture. In addition to the healing property, incorporating silica fume reduces the consumption of cement, thereby reducing the air pollution caused by the cement industries as well as resulting in the production of eco-friendly concrete.