Study On Light Wall Material By Composited With Bamboo And Cement

With the requirement of building economical society and the energy saving as a national policy, the environment-friendly and energy-saving building materials are going to be the development direction of new building materials. Thus the study of high-strength, economic and fireproof, lightweight porous sound-absorbing material is no time to delay. The light wall material that composited by processing residue of bamboo and cement is not only an excellent of green building materials, but also an important popularized of building wall materials in china. By studying on the light wall material by composited bamboo and cement, it can not only effectively solve the problem of shortage of timber resources, but also avoid the release harmful gases from organic synthetic adhesives. And the organic synthetic adhesives can reduce the cost of petrochemical resource effectively. So it has broad application prospect and significant value on academic research.This paper firstly studies the effect of coagulant agents and the dosage by measuring and analysis of the temperature of cement hydration, then confirms the optimal the foaming process and ratio of raw materials through,.; orthogonal experiment,and do the test of performance enhancements to get the optimal composite process of lightweight wall material by composited with bamboo and cement. The composite mechanism are analyzed by infrared spectroscopy (FTIR), scanning electron microscopy method (SEM), thermal gravity analysis (TG/DTG).The main results are obtained as follows:(1) bamboo has inhibiting and hysteresis effect on cement hydration, the smaller size of bamboo powder, the greater effect for cement hydration. Comparison several kinds of coagulant, CaCl2has the best effect, and lower price, is convenient in the practical application. Take CaCl2as a coagulant, the more dosage add, the greater effect of promoting cement hydration, but in practice, if the more coagulant adds, not only causes the metal components corrosion, but also the higher costs. By compare the effects of different dosage of coagulant for cement hydration, the suitable dosage of coagulant is5%to7%.(2)Main foaming process factors including the type of foaming agent, dosage and foaming temperature on properties of the light wall material by composited with cement and bamboo have the different degrees of influences. Analysis through orthogonal experiment, the results show the optimum foaming process combination of the light wall material by composited with cement and bamboo included foaming agent of Mg powder, its dosage of3%, the foaming temperature of70℃. The density of light wall material was535kg·m-3, and its thickness swelling (TS) is0.63%, and its modulus of rupture (MOR)0.83MPa when light wall material was manufactured by adopting the optimum foaming process combination.(3) Main foaming process factors including water/cement ratio, bamboo/cement ratio, PVA/cement ratio, pretreatment method have the different degrees of influences. By analyzing the test results, the water/cement ratio has a significant effect on the each performance of the material, and play a key role to overall performance of the material. Then the optimum of ratio of material and process are as follow:water/cement ratio is1.75, bamboo/cement ratio is30%, PVA/cement ratio is2.5%, bamboo particle through hot-water pretreatment.(4) Different methods of performance optimization have different effect on the performance of light wall material. By analyzing the test results, to improve the overall performance of the material, then get the best optimization method is mixing2%bamboo fiber, its performance is as follow:the density is490kg·m-3, MOR is0.96MPa, compressive strength is1.37MPa, TS is0.55%, the thermal conductivity is0.065W·m-1·.K-1, the average absorption coefficient is87%.(5) FTIR analysis shows that the pretreatment can improve compatibility between cement and bamboo, and the hot-water pretreatment is better conducive to remove inhibition substances of bamboo than1%NaOH solution pretreatment, to improve the compatibility between bamboo and cement, to improve the overall strength of material. Different water/cement ratio have no significant effect on early stage of cement hydration, but with the water/cement ratio increase the Ca(OH)2crystalline phase produces decrease in late stage.(6) By SEM analysis, bamboo contains inhibition substances, and the closer to the bamboo the greater degree inhibition on the cement, even the part of early and middle stage of crystalline phase cannot be transformed into lamellar crystalline phase in later stage. Hot-water pretreatment is better conducive to remove the inhibition substance than1%NaOH solution pretreatment, and improves the compatibility between bamboo and cement. Hot-water pretreatment have the better and lager degree of foaming than1%NaOH solution pretreatment, and more uniform distribution. Without pretreatment, the bamboo contains inhibition substances, and the hydration setting of the cement paste is slow, at the same time early its strength is decrease.There are some small pores crack and collapse because stress and irregular voids are formed, and the strength has a sharp decrease.(7) By TG/DTG analysis, the piece through hot-water pretreatment forms more crystalline phase, and hot-water pretreatment is conducive to remove the inhibition substance of bamboo and improves the compatibility between cement and bamboo, also improve overall material strength of material. If the substances have more lager effect on forming Ca(OH)2crystal phase, Aft crystalline phase and C-S-H gel are formed less. When the bamboo have a pretreatment can greatly improve the compatibility between cement and bamboo, the strength of material can increase. Different water/cement ratio piece have nearly weight loss.When water/cement ratio is1.75, the weight loss is the lowest, crystalline phase forms the most. When the water/cement ratio reached1.80, Ca(OH)2crystal phase and the strength of the material are not conducive to form.