Influence of different mineral and chemical admixtures in OPC with river sand and comparison with standard sand on durability properties

摘要

The supplementary cementious materials (SCM) or mineral admixtures like fly ash, silica fume, metakaolin and ground granulated blast furnace slag are used in cement composite by partial replacement of cement about 20%. The effect of SCMs in Ordinary Portland cement with regard to water requirement for consistency, setting time and cement mortar cubes with and without addition of superplasticiser has been studied. It has been observed from the experimental studies that the cement consistency for OPC is 27.5% and addition of different mineral admixtures demands more water than cement consistency. Particularly, the mix with metakaolin demands 39% water for consistency. The effect of SCMs in Ordinary Portland cement with regard to durability properties of cement mortar cubes with and without addition of superplasticiser also been studied. The durability properties such as water absorption, chloride permeability, sorptivity and permeability are studied in present study. Water absorption for cement composite cubes prepared using Standard sand is more when compared to cubes cast using River sand. Among the mixes with river sand it is found that the mix with metakaolin showed better results i.e. the rate of water absorption is less compared to all other mixes. And also with standard sand it is found that silica fume showed better results i.e. the rate of water absorption is less compared to all other mixes. That the rate of penetration of chlorine and capillarity of water is high at initial stages and as the time increases the penetration or absorption rate is decreases. It is also observed in the case of mix using river sand the mix with metakaolin performed better with regard to sorptivity and chlorine resistance. And in the case of standard sand the mix with silica fume performed better with regards to sorptivity and chlorine resistance. From the permeability test that the porosity for the mortar cubes cast using standard sand is less compared to cubes cast using river sand and it is also observed that the mix with metakaolin mortar cubes absorbed less water in the case of river sand, the mix with silica fume mortar cubes absorbed less water in the case of standard sand, and thus it indicates the porosity is less for those cubes.