Using para rubber mixed in moderate lightweight concrete

Abstract

This research is to use latex from para-rubber as an admixture for improving the strength and insulation properties of autoclaved aerated lightweight concrete. In mix design, cement-sand ratio is 1:1 (by weight). The aluminum powder (3% by weight) is added, water-cement ratio is 0.5 (by weight not include water in latex), five percent of lime and gypsum (by weight of cement) are added. To provide latex from para-rubber, the solution of ammonia at 15% of concentrdtion is added into para-rubber at amount of 3% (by weight of para-rubber). Concrete must be added 4% (by weight of cement) of the nonionic surfactant. The latex per cement ratios that use in this experiment are 0, 0.10,0.15 and 0.20 (by weight of cement). Then mixing and streaming follow TIS (Thailand Industrial Standard) and test the density by volume, compressive and bending strength at ages of 3, 7, 14 and 28 days. The absorption of water is measured at 7 and 28 days. The elongation and coefficient of thermal conductivity are measured under ASTM standard. From the results, it is found that the compressive strength and density of lightweight concrete reverses variation with latex-cement ratios while the bending strength and water absorption of concrete is Propostion to latex-cement ratio. The elongation has an uncertainty for each latex-cement ratio. The coefficient of thermal conductivity is slightlg larger than normal lightweight concrete. The suitable latex-cement ratio is 0.10 (by weight of cement). By consider all of results, this can be produced as a moderate light Weight concrete in which high strength and good insulation are highlighted.