Development And Modification Of Low Density Foam Concrete

In order to solve the problems of low strength and shrinkage of low-density foam concrete,this paper uses P.0 42.5 cement as the main cementing material to make foam concrete,which is modified by adding fine sand and fiber.Firstly,the influence of foam and water reducer on the physical properties and mechanical properties of foam concrete was studied by single factor experiment.The suitable dosage of each component was determined.Then the orthogonal design method was used to optimize the multi-factors to obtain the mixture ratio.A04 and A05 grade low density foam concrete.On this basis,the two kinds of tailings sand were used to replace the cement,and the three kinds of fibers were added to modify the foam concrete.Research indicates:(1)After admixing appropriate and appropriate amount of admixture,A04 and A05 two grades of foamed concrete can be obtained by using ordinary Portland cement.(2)The type of tailings sand has a significant effect on the compressive strength of foam concrete.In the case of tailings sand replacing 20% of cement,for grade A04 foam concrete,both tailings sands reduce the strength of the specimens to a large extent,and the Maanshan tailings sand has the largest reduction;for the A05 grade foam concrete,Maanshan still reduces the strength,but The reduction is reduced,and the Huaiyuan tailings sand can maintain the strength unchanged.(3)The incorporation of tailings sand effectively inhibits the shrinkage of low-density foam concrete.After replacing 20% cement with two kinds of tailings sand,the linear shrinkage of A04 and A05 foam concrete decreased by about 30%.The replacement of cement with suitable tailings can significantly reduce the shrinkage of low-density foam concrete while maintaining the same strength and density.At the same time,the industrial waste is fully utilized,and the cement is greatly saved,and the technical and economic effects are obvious.(4)Different varieties of fiber have different effects on the performance of low density foam concrete.The two kinds of fibers doped with CHP and DHP greatly increase the density of foamed concrete.Under the same density,the compressive strength is also greatly reduced.However,with MTF fiber,the change of bulk density of foamed concrete is small,and the compressive strength is greatly improved;All three fibers significantly improve the bending toughness of foam concrete.