Investigation of Compression Strength and Heat Absorption of Native Rice Straw Bricks for Environmentally Friendly Construction

Abstract

The purpose of this study was to compare the efficiency of native rice straw mixed bricks, prototype bricks and brick blocks that are sold in the market. The comparison looked at four aspects, as follows: (1) compression strength, (2) heat absorption, (3) weight of the brick and (4) price. In this study, the native rice straw species from the Pa Pae sub-district, Mae Sariang District, Mae Hong Son Province, Thailand, were used to replace cement, sand and stone in 200, 300, 400 and 500 g amounts. The ingredients were then mixed and put into a hand-pounded mold. When the extrusion was finished, it was removed from the mold and cured for 7, 14 or 28 days. Brick block performance was then tested. The results showed that 200 g of native rice straw mixed with cement brick had the best performance in all four aspects. The 200 g native rice straw mixed with cement brick was able to bear the weight of 1.26 kg/cm2. It had the best heat transfer and was able to reduce the temperature inside the brick-block construction by 10 degrees Celsius. Its weight per brick was 7.59 kg and the price was only 3.17 baht ($0.09 USD) per brick. In conclusion, the native rice straw mixed bricks had low thermal conductivity, are attractive for energy saving when used as wall insulation and are suitable for environmentally friendly construction.