Research On The Durability Of Hemp Thread Modified Foam Concrete Used To Roof

Currently,the thermal conductivity and strength of the foam concrete and other aspects have been world-widely studied.The technology is maturing,which can improve the performance of foam concrete,such as changing admixtures,admixtures and the addition of foam.However,as an inorganic porous material,durability problem of foam concrete has become more prominent.A large number of pores were left caused by the water lost in the curing process and that consumed by cement-based binding materials itself,making its absorption much larger than similar organic materials,so that its durability has become a bottleneck,which restrict its development such as resistance to wet and dry cycles,acid corrosion resistance and waterproofing properties.After mixing with fiber,the foam concrete obtained capillary pores and artificial pores,and its unique pore structure with intricate fiber makes its physical performance more complex than ordinary foam concrete.In this paper,by adding flax fiber the foam concrete was modified,which aimed at defects of foam concrete,such as high dry density,low strength,large shrinkage,high water absorption,low corrosion resistance.Meanwhile,using the hydrogen peroxide chemical foaming method,foam concrete modified by flax fiber with different structural hole characteristics was obtained,and its physical properties of dry density,water absorption,thermal conductivity,compressive strength and resistance to wet and dry cycles,resistance to sulfate attack,waterproof durability were tested.The effects of different addition of flax fiber and admixtures on durability of foam concrete modified by flax fiber were studied,which provided a theoretical basis for improving the durability of foam concrete modified flax.The results showed that physical properties and durability of the foam concrete was modified by control the amount of added flax fiber and admixture.The addition of flax fiber was 1.2kg/m3,the resistant ability of dry and wet was obvious and at the dosage of 1.5kg/m3,-the sulfate resistance and waterproofing property were optimum.The hydrogen peroxide was 6.5%,sulfate resistance and waterproof properties were optimum.The addition of anhydrous sodium sulfate was 6%,the dry and wet resistance and waterproofing were optimum.The addition of rubber power was 0.2%,the resistant ability of dry and wet and sulfate resistance and waterproofing property were optimum.The optimum mixing ratio of high durability of foam concrete modified by fax fiber was obtained,the dosage of added flax fiber was 1.2kg/m3?1.5kg/m3,addition of anhydrous sodium sulfate was 6%-8%and hydrogen peroxide solution was 5.5%?6.5%,and the rubber powder was 0.15%-0.2%.The dry density and volume water absorption of foam concrete modified by flax fiber was investigated,dry wet recycling coefficient,resistance to sulfate erosion intensity coefficient,and trend of softening coefficient curve were coMParatively analyzed with the heat conduction coefficient curve,and the investigation was based on research of physical properties and durability referring to single factor.It provided the corresponding relation between the durability index and the direction and theoretical basis for the durability of foam concrete modified by flax fiber.