Study On The Composite Block Of Straw Brick And Concrete

With China’s emphasis on promoting the construction of energy-saving work and the development of science and technology, agricultural straw as a new building material is feasible, not only be able to recycle, but also can replace clay bricks, to achieve the purpose of saving land resources. Thus, the new straw wall material has a great contribution to the construction of energy-saving.In order to meet the needs of building energy efficiency,in view of the poor thermal insulation performance of concrete hollow block bearing walls which are used in rural areas of Chongqing,this paper presents a composite block of straw brick and concrete which can meet the bearing and thermal insulation requirements, combined with the material properties of rice straw stalk to develop a new straw brick molding process, filling in the concrete hollow block hole with the straw brick, finally successfully developing a composite block of straw brick and concrete which has low cost and convenient construction, and its basic properties are studied experimentally.The paper studied on straw brick molding method firstly, by comparing different ways of acid treatment, alkali treatment, bonding treatment. According to the forming effect of rice straw brick and the simple operation, firstly determining the way of alkaline treatment for straw brick molding:after soaking rice straw stalk by the application of 1%- 8% concentration of sodium hydroxide solution 20-24 hours, using it to make brick. Then the basic properties of the formed straw bricks were studied: the size of 140 x 130 x 190 mm was determined, the straw brick has the advantages of small density, excellent thermal insulation performance, good corrosion resistance and so on.Comparing the molding effect and basic properties of the 1%-8% concentration of sodium hydroxide solution in the form of straw brick,finally determine the sodium hydroxide concentration is 2%-5%.The basic properties of the composite block of straw brick and concrete were discussed finally. Determining the size of the composite block is 200 x 190 x 190 mm,the thickness of concrete layer is 30mm; the composite block that consisted of the straw brick that made by rice straw stalk which were soaked in sodium hydroxide solution of 2%-5% concentration, its thermal conductivity is 0.056-0.126 W/(m · K), the composite block’s thermal conductivity is only slightly larger than the internal straw bricks’ 0.038-0.086 W/(m · K), far less than the thermal conductivity of Chongqing rural building’s common concrete block and brick, it is a building material with good heat preservation to meet the needs of thermal insulation performance requirements on rural building, the compressive stress of composite block is 6.00 Mpa in average, it is better than the 5.00 Mpa stress standard of general bearing blocks, and its fire resistance limitsup to 3 hours, be available in the B1 class construction of fire safety requirements.Through the study, we can know that the composite block has good properties of compression, durability, fire prevention, thermal insulation and so on, the production process is simple, the economic effect is good, it is a kind of rural building material with the advantages of heat preservation, energy saving, environmental protection and so on.The results of the researches show that the developed composite block of straw brick and concrete can meet the requirements of the load bearing and thermal insulation of the rural buildings in Chongqing area,and it has a certain durability and fire resistance,be suitable for rural building in Chongqing.