Durability of fly ash based geopolymer concrete infilled with rubber crumb in seawater exposure

Abstract

Geopolymer is an alternative binder to replace Ordinary Portland Cement (OPC)in construction industry. Source materials that rich in silica (Si) and alumina (Al) were activated by using alkaline solution. Production of tires keep increasing every year and due to its non-biodegradable properties it causes problems for disposal process. In current scenario, waste materials should be used or recycled so that the existing natural resources can be saved and at the same times it can protected environment. In this paper, the effect of rubber crumb on fly ash based geopolymer concrete have been investigated by immersing the samples in seawater for 28 and 60 days. The rubber crumb was used to replace coarse aggregates from range 5% until 20%. The ratio of fly ash/alkaline activator and sodium silicate/sodium hydroxide(NaOH) ratio were fixed at 2.0 and 2.5. It has been shown that the compressive strength decreased when the content of rubber crumb increased. The highest compressive strength (39.6 MPa) was obtained at 5% replacement of rubber crumb when exposure to seawater for 28 days. The density of geopolymer samples also increased when immersed in seawater for all samples. The lack of bonding between rubber crumb and geoplymer paste cause increasing in porosity hence reduced the strength, increment in density and changes in weight of geopolymer samples.