The Study On Slag-magnesia Cement Sandwiched With Foamed Concrete Sandwich Panel

According to the energy saving development compendium of "eleventh Five-Year Plan", the important energy saving field is building energy conservation, industry energy conservation and transport energy conservation, the most quantity energy using is building. it is important to improve the wall materials of our country, studying new energy saving wall materials is a important mission for the researcher.In this article, develop paddy fiber cement foam heat preservation Wall materials by analyzing the crop straw resource and the characteristic of different areas, And try to use new cement materials to substitute Portland cement for saving natural resources and reducing the environmental pollution. The system of "slag-magnesia-alkali" cement is studied. The main work is to optimize the mix proportion of mass of the raw materials. On the premise of the enough mechanical properties and physical properties of this cement material, by reducing the mass of alkali can lower the cost and save the natural alkali resource. Adding a small amount of sawdust into the cement material can enhance its flexural strength and improve its ductility. After several experiments, the final mass mix proportion is Slag:MgO:Sodium Silicate:KOH=60:40:15:1; and the adding rate of sawdust is 5%by mass. W/B (The B is total quantity of Slag and MgO) is 0.45. The new cement density is 1892.45 kg/m3; the compressive strength is 32Mpa; the flexural strength is 4.3Mpa; Water absorptivity is 16.86%. This cement material is of practical use in case of dampness, has good mechanical properties, overcomes defects such as warpage and deformation that has Sorel cement peculiarly.The forming technology of the paddy fiber and expanded polystyrene granule foamed concrete is studied in this article. The paddy fiber has a bad influence for the condensation of Portland cement, so alumina cement is used for the foamed concrete because of its low alkalinity. As for the foamed agent,3 kinds of blowing agent are chose. By comparing their foaming power and the length of time for foam stabilizing, plant Albumen foam agent produced by Yantai Shiyong Company is selected. Add a little amount of Sodium Silicate as foam stabilizer to prolong the length of its foam stabilizing time. To reduce the density of the final foamed concrete and improve its heat resistant property, certain amount of expanded polystyrene granule is added. The optimization mix proportion is as follow. W/C is 0.311; and the expanded polystyrene granule is 8%of the cement by mass. The paddy fiber is 50%of total cement and expanded polystyrene granule by volume; the polyvinyl acetate (PVA) is 1% of the cement by mass. The volume of foam is 1050ml per 900g cement. The concrete density is 825.90 kg/m3; the compressive strength is 1.8Mpa; Water absorptivity is 27.7%.After the study of the slag-magnesia cement and the paddy fiber and expanded polystyrene granule foamed concrete, slag-magnesia cement sandwiched with foamed concrete sandwich panel is produced as heat-conservation wall material used in the rural areas. Some of its mechanical properties are tested. Its bending load is 3349.83N and deflection is 1.5mm.