Use of Para-rubber to Improve Strength and Insulation Properties of Autoclaved Aerated Lightweight Concrete

Abstract

The aim of this research is to use latex from para-rubber as an admixture for improving thestrength and insulation properties of autoclaved aerated lightweight concrete which has bubbles. In mixdesign, cement-sand ratio is 1:1 (by weight). The aluminum powder 3% by weight is added, watercementratio equal of 0.5 (by weight not include water in latex), five percent of lime and gypsum (byweight of cement) are added. To provide latex from para-rubber, the ammonia solution (concentrate15%) is added into para-rubber in amount of 3% by weight of para-rubber. Nonionic surfactant of 4% byweight of cement is added in concrete. 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)1505-2541 and test the density, compressive and bending strengths at ages of 3, 7, 14 and 28 days. Theabsorption of water is measured at 7 and 28 days. The elongation and coefficient of thermal conductivityare measured. From the results, it is found that the compressive strength and density of lightweightconcrete reverses variation with latex-cement ratio while the bending strength and water absorption ofconcrete is proportion to latex-cement ratio. The elongation has an uncertain result for each latex-cementratio. The coefficient of thermal conductivity is slightly larger than that of normal lightweight concrete.The suitable latex-cement ratio is 0.10 (by weight of cement). From all of the results, latex from pararubbercan produce a moderate lightweight concrete in which high strength and good insulation arehighlighted.