| Based on solving raw soil bonding materials in the modernization construction in rural area of China facing the low compressive strength, tensile bond strength, dry shrinkage, easy to crack and so on. Researched performance optimization mechanism and key technology of materials based on earth and effectively overcome the defects in the mechanics performance, durability and so on according to the undisturbed soil types in Shanxi Chin. To explore and utilize the raw soil material ecological potential, researched and developed series of new products and its processing technology of raw soil material, the ecological value of raw soil material in building Chinese rural areas to obtaining a suitable apply position and play space, and promote the healthy and sustainable development of rural construction. The main progress of research work are as follows:Through compounding raw soil in Shanxi and inorganic cementitious materials prepared earth bonding materials and contrasting bonding materials slurry and hardened body performance, graduate of subgrade binding material performance evaluation method.Study on mechanical properties of Shanxi loess under the action of inorganic cementitious materials and chemical admixtures. The results show that slag modified effect is much better than cement in strength, at the same time, the bonding materials changed by slag is easier to crack than modified cement. Composite slag and cement can give full play to each other’s advantages, in the total content less than 15.0%, maximum strength of blocks modified by cement only can be 7.3MPa and the maximum intensity is 9.2MPa while modifying blocks through compositing slag and cement, strength up to 26.0%. In common admixtures,0.5%～1.0% NaOH and 1.5%～2.0% sodium sulfate increased raw soil bonding materials strength modified by cement slightly. When composite cement and slag and the total volume is less than 15%, there are different degree of strength enhancement with sodium sulfate for hardening, while, calcium chloride would produce negative impact on strength when slag is small.The mechanism of calcium chloride and sodium sulfate enhance raw soil bonding materials modified by cement and slag were studied. The results showed that sodium sulfate can not excite activity of raw soil well, the strength of bonding materials modified by sodium sulfate increased mainly by promoting the Aft formation. Secondly, calcium hydroxide as companions of Aft production also increased. Similar to sodium sulfate, calcium chloride can not excite activity of quartz in the raw soil material very good, hydration reaction of bonding material system participated mainly by cement, slag and part of active silica, alumina.The strength of bond strength and resistance to dry shrinkage crack resistance and evolution process of raw soil plaster material composite latex, rice straw fiber, sand, cement, raw soil was studied. The results show that latex can retard the cracking, crack repair, improve bond strength. 0.3% rice straw fiber can play effect of reinforcement and toughening, reduce the crack number and crack length. Sand can be used as the skeleton to play a supporting role to reduce drying shrinkage. Cement can afford C-S-H gel through hydration reaction, improve the bond strength and reduce the crack. When the components are used at the same time, the mode of action between each components and the structure of system will continue to change with the hydration process and the process of moisture migration. Raw soil plaster materials formed strength system gradually with inorganic cementitious and raw soil as the main body, fiber, fine aggregate and polymer emulsion as the auxiliary, so as to improve strength and the ability of resisting dry shrinkage cracking. |
