Research On The Improvement Of Water Absorption Of Foamed Cement

Thanks to its internal unique porous structure,foamed cement has the outstanding advantages of light weight,heat preservation,heat insulation and so on,and it is fully used in energy saving material,heat preservation roofing,external wall heat insulation and other many aspects.However,due to its porous structure,and the cementitious material is the main raw material,so in terms of durability,especially the water absorption performance,foamed cement performance is not outstanding.When the foamed cement is in a multi water environment,its mechanical properties will gradually weaken,thus affect its durability,which seriously affects the use of foamed cement.Therefore,it is very important to develop low water absorption rate and high strength foamed cement.In this paper,we use ordinary Portland cement as cementitious materials,and prepare foamed cement samples with physical foaming method.First discusses the water cement ratio,bulk density,micro silicon powder,polypropylene fibers and other macro factors on properties of foamed cement especially water absorption effect,and optimizing the best mixture ratio.And on this basis,using the internal mixing type test method,studied the calcium stearate,methyl potassium silicate,a home-made silicone three waterproofing agent to design the bulk density is 550kg/m~3foamed cement water absorption performance.Finally,selected optimal waterproofing agent and its optimal dosage,get the optimal mixing proportion.Through the experiment,we get:The increase of water cement ratio will result in the increase of volumetric water absorption rate of foamed cement,and the mechanical property of foamed cement is the best when the water cement ratio is 0.35.Bulk density had a direct effect on the water absorption of foamed cement,and the water absorption rate decreased with the increase of bulk density;Micro silicon powder and polypropylene fiber mixed in foamed cement,had little effect on its water absorption rate,but can significantly increase its compressive strength;After incorporation waterproofing agent,the water absorption rate of the foamed cement is obviously decreased,and the compressive strength of the foamed cement is increased,and the minimum increase is 23.1%.Among them,the hydrophobic effect of a home-made silicone is the best,when its dosage of cement is 1.0%,the 24h volumetric water absorption rate of foamed cement is 2.3%,which is obviously better than the existing research of 5%.