Study On The Preparation And Performance Of Solid Waste-Based High-strength Foamed Concrete

In recent years,the development and application of energy-saving insulation building materials have received more and more attention.How to obtain high-strength,low-density building insulation materials has always been the goal and direction that people pursue.As a new type of building material,foamed concrete is characterized by light weight,can absorb solid waste,and has the characteristics of flame retardancy,heat preservation,heat insulation and sound absorption,so it has been widely used in building construction.However,the density and strength of currently commercially available foamed concrete products can only reach the national minimum standards.Therefore,it is necessary to further improve the strength of foamed concrete.A series of experiments have been carried out in this paper.The research contents and results are as follows:(1)Three methods are used to improve the strength of foamed concrete,namely carbonated modified carbide slag,pressurized foaming,and test block alkali leaching carbonation.The three methods have a certain degree of strength on the test block.Promote.The experimental results show that the best ratio under the experimental conditions is fly ash:calcium carbide slag is 7:3,calcium to silicon ratio is 4:5;when the modified amount of calcium carbide slag is 2.5%,the strength reaches the maximum,which is 4.7 MPa.The ordinary test block has increased by 52%,while the density has increased by 10%;when the foaming pressure is 10N,the strength of the test block reaches the maximum value of 10.4MPa,which is 236%higher than the ordinary test block,but the density has also increased by 34%;alkaline immersion When the carbonation time is 6h,the strength of the test block is the best,reaching 4.4 MPa,which is 42%higher than the ordinary test block,and the density is increased by 4%.Through the combined experiment of several methods,it is concluded that the carbonation modification and The use of alkali immersion carbonation together will reduce the compressive strength of the test block.The test block prepared by carbonation modification and pressure foaming has the highest strength,which is 12.3 MPa.The order of the three methods to increase the strength is pressurized foaming>alkali immersion carbonation>carbonation modification.(2)The effect of process conditions on the performance of the test block under pressure foaming conditions is studied,and the comparison is made with the normal pressure test block.The results show that pressurized foaming will make the pore structure of the test block more dense,the pore size more uniform,and the number of connected holes is less than that of the normal pressure test block;the experiment shows that the compressive strength of the test block will increase with the aluminum powder blending.When the foaming temperature is at 50℃,the performance of the test block obtained will reach the best;too much aluminum powder,too high water-cement ratio,and too high foaming temperature will lead to atmospheric pressure test The block collapses,and the use of pressure foaming can effectively inhibit the slurry foaming collapse,and at the same time,it can significantly shorten the resting time of the test block,and significantly improve the compressive strength of the test block,but at the same time the density of the test block is also significantly increased.;The compressive strength of the foamed concrete made in this experiment using the best process conditions can reach 10.4 MPa and the density is 824.7kg/m~3;the corresponding demolding time at 50℃static curing temperature is 60 min,which is only normal pressure foaming static curing 1/7 of the demolding time can greatly improve the production efficiency of the test block;under the experimental conditions,the optimized foaming pressure is 10 N,the aluminum powder content is 1‰～5‰,and the water-cement ratio is 0.5～0.6.The foaming temperature is about 50℃,so that high-performance foamed concrete with a compressive strength of 5-10 MPa and an absolute dry density of 500-850 kg/m~3 can be prepared.