水泥、地聚合物气泡混合轻质土工程特性试验研究

发布时间：2018-06-16 10:42

本文选题：气泡混合轻质土 + 水泥　；参考：《东南大学》2015年硕士论文

【摘要】：原位土、固化材料和气泡混合制备而成的气泡混合轻质土是一种新型的填土材料,具有轻质、自立性良好、施工工期短、废物再利用和环保节能等优点,可广泛应用于地下工程回填、路堤填筑和港口建设等方面。本文以南京下蜀土为原料土,预制泡沫为轻质材料,分别以水泥和地聚合物为固化材料制备气泡混合轻质土,对气泡混合轻质士水稳性、吸水性、渗透性、物理力学性能、干湿耐久性,硫酸钠溶液浸泡耐久性和微观机理进行了试验研究。取得如下主要成果：(1)通过吸水性和渗透性试验,对比研究了水泥轻质土和地聚合物轻质土的吸水性和渗透性。结果表明,地聚合物吸水能力更强,渗透系数高于水泥轻质土。(2)通过无侧限抗压强度测试,明确影响水泥轻质土和地聚合物轻质土强度的主要因素,并对两者进行比较。结果表明,相同掺量和密度条件下,地聚合物轻质土强度是水泥轻质土的2倍；影响水泥轻质土和地聚合物轻质土强度的主要因素是Vv/Vc(孔隙体积和固化剂体积之比),且得到qu=A/(Vv/Vc)B的经验公式并提出一种制备气泡混合轻质土的方法,以便工程应用。(3)通过水稳性试验,对比研究了水泥轻质土和地聚合物轻质土水稳定性。结果表明,地聚合物和水泥轻质土均有良好的水稳性。(4)通过一维压缩试验,研究了水泥轻质士和地聚合物轻质土变形特性。结果表明,其屈服应力和屈服后压缩指数与Vv/Vc呈线性关系,且屈服应力随Vv/Vc增大不断减小,屈服后压缩指数随Vv/Vc增大不断增大。根据结构性上的修正剑桥模型给出压缩曲线预测流程图,给工程应用提供一定参考依据。(5)通过干湿循环试验和硫酸钠溶液浸泡试验,对比分析了水泥轻质土和地聚合物轻质土干湿循环耐久性和硫酸钠溶液浸泡耐久性。结果表明,水泥轻质土干湿循环耐久性要略优于地聚合物轻质土,硫酸钠溶液浸泡耐久性明显不如地聚合物轻质土。(6)通过压汞试验、扫描电镜试验和热重分析试验,对比分析了水泥轻质士和地聚合物轻质土的孔隙特征、水化产物形态和数量。结果表明,水泥轻质十的孔径分布区间主要集中在0.1～5 μm和5～100 μm,地聚合物轻质土的孔径分布区间主要集中在0.01～0.2μm和5～100μm：水泥的主要水化产物为CSH和AFt,地聚合物的主要水化产物为CSH。
[Abstract]:In situ soil, solidified material and bubble mixed light soil is a new type of filling material. It has the advantages of light weight, good independence, short construction period, waste reuse, environmental protection and energy saving, etc. It can be widely used in underground engineering backfill, embankment filling and port construction. In this paper, using Nanjing Xiashu soil as raw material, prefabricated foam as light material, and cement and geopolymer as curing materials, bubble mixed lightweight soil was prepared, and its water stability, water absorption, permeability, physical and mechanical properties were studied. The dry and wet durability, soaking durability and microscopic mechanism of sodium sulfate solution were studied. The main results are as follows: (1) the water absorption and permeability of cement lightweight soil and geopolymer lightweight soil are studied by water absorption and permeability tests. The results show that geopolymers have stronger water absorption and permeability coefficient is higher than that of cement lightweight soils. The main factors affecting the strength of cement lightweight soils and geopolymer lightweight soils are determined by testing the unconfined compressive strength of the two soils, and the two factors are compared. The results show that the strength of geopolymer lightweight soil is twice as high as that of cement lightweight soil under the same content and density. The main factor that affects the strength of cement lightweight soil and geopolymer lightweight soil is the ratio of pore volume to curing agent volume, and the empirical formula of quang A / V / V / V cu B is obtained, and a method of preparing bubble mixed lightweight soil is proposed. Through the water stability test, the water stability of cement lightweight soil and geopolymer lightweight soil was studied. The results show that both geopolymer and cement lightweight soil have good water stability. The results show that the yield stress and the post-yield compression exponent are linearly related to V _ v / V _ c, and the yield stress decreases with the increase of V _ v / V _ c, and the compression exponent after yield increases with the increase of V _ v / V _ c. According to the structural modified Cambridge model, the prediction flow chart of compression curve is given, which provides a certain reference for engineering application. The dry and wet cycle test and soaking test of sodium sulfate solution are carried out. The dry and wet cycle durability and soaking durability of cement lightweight soil and geopolymer light soil were compared and analyzed. The results show that the durability of dry and wet cycle of cement lightweight soil is slightly better than that of geopolymer light soil, and the durability of soaking in sodium sulfate solution is obviously inferior to that of geopolymer light soil. (6) through mercury injection test, scanning electron microscope test and thermogravimetric analysis test, The pore characteristics, hydration product morphology and quantity of cement lightweight soil and geopolymer lightweight soil were compared and analyzed. The results show that The pore size distribution range of cement is mainly 0. 1 渭 m and 5 渭 m, and that of geopolymer light soil is 0. 01 ~ 0. 2 渭 m and 5 ~ 100 渭 m. The main hydration products of cement are CSH and AFtand geopolymer. The main hydration product is CSH.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU41

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