【作者】 陈光耀；

【导师】 樊粤明；

【作者基本信息】 华南理工大学 ， 材料学， 2010， 硕士

【摘要】 水泥基渗透结晶型防水剂(简称CCCW)作为一种独特的刚性防水材料,因防水效果持久、自愈合性能好等特点,具有广阔的市场前景。然而,对于其渗透结晶和裂缝自愈合等作用机理,目前说法不一,缺乏有说服力的理论解释。该产品性能良莠不齐,严重阻碍了在国内的推广使用。因此,通过对机理的深入研究并开发出具有自主知识产权的CCCW,对于提高我国防水工程的质量有着重大的现实意义。本文在对裂缝自修复作用机理的研究基础上,提出了循环络合结晶—裂缝自修复反应机理,认为研制该类防水剂的关键技术是络合剂的研发及制备,试图为水泥基渗透结晶型防水材料的制备和应用奠定理论基础和技术支撑。研究工作主要围绕以下几个方面展开:1)制备出络合剂并对其作用机理进行研究;2)以混凝土的综合性能为目标,采用复合技术配制出一种水泥基渗透结晶型防水剂,并对其配方进行优化;3)通过设计实验对自制防水剂的自修复性能进行考察;4)探讨防水剂对混凝土其它性能的影响,并由相关检测部门对自制防水剂的基本性能进行测试与评价。循环络合结晶—裂缝自修复反应机理的核心是掺入到水泥基材料中的络合剂可循环发生络合结晶反应,不断生成的不溶性物质对裂缝产生自修复作用。络合剂JS的作用机理及其对胶砂的防水性能研究表明:相同摩尔浓度下,络合剂JS较硅酸根先与钙离子发生络合反应,快速生成钙络合物沉淀析出,随反应时间延长,该钙络合物与硅酸根反应转化为水化硅酸钙,并把JS置换出来,JS在总的反应过程中并不损耗;遇水后钙络合物的快速结晶和它与硅酸根的反复置换,不断生成水化硅酸钙填充水泥胶砂的孔隙和裂缝,从而显著提高水泥基材料的抗渗能力,并赋予基体裂缝自修复功能。本文以复合技术路线来配制水泥基渗透结晶型防水剂。通过正交设计和单因素优化实验,以络合剂JS、活性硅助剂、无机防水助剂、有机硅防水助剂、减水剂和硅灰作为原材料,在实验室研制出具有良好防水能力和自修复性能的结晶型防水剂。根据国标GB 18445-2001《水泥基渗透结晶型防水材料》规定的实验方法和技术要求,对自制防水剂的性能进行研究测试。结果表明:防水剂的各项性能指标均符合标准求,其中渗透压力比(28 d)达到275%;二次抗渗压力(56 d)为1.3MPa,高于一次抗渗压力。通过带裂缝水泥基材料的渗漏实验及XRD衍射、SEM显微等分析结果表明:暴露于水环境中的水泥基材料,因氢氧化钙的溶出和沉积、及碳酸钙的形成而发生裂缝自愈合作用,但自愈合能力较弱;掺有自制防水剂的水泥净浆和砂浆试件其裂缝自修复能力较空白样显著,且具有较好的二次自修复作用;防水剂既可发生化学反应,生成结晶沉淀物来填充孔隙,还可以促进基体裂缝表面水化硅酸钙的形成,从而实现水泥基材料的裂缝自修复作用。更多还原

【Abstract】 The cementitious capillary crystalline waterproofing agent (CCCW) as a unique rigid waterproof material,characterized by it’s permanent waterproofing effect,self-rehabilitating ability and so on,has a broad market prospect. However, the mechanism of its crystallization and seal-healing for cracks presents different opinions, and does not have a complete and accurate theory. In the domestic market, the performance of such materials varies greatly, seriously affecting its promotion and application. Therefore, through the mechanism of in-depth research and developed the CCCW with independent intellectual property rights, can stsndardize and promote the kind of material production and application in China, for the improvement of waterproofing engineering is of great practical significance.In this paper, based on analyzing the mechanism of self-healing function cracks, the mechanism of circulating complexing crystallization– self-healing reaction for cracks is proposed for the first time. It is considered that selection and characterization of complexing agent is the key technique for production of such waterproofing agent, hopefully providing the theoretical foundation and technical support for the preparation and application of CCCW. Research work is mainly focused on the several aspects as follows: 1) a novel kind of self-healing materials for the cracks of concrete was prepared, and researched its self-healing ability and working mechanism; 2) a crystalline waterproofing agents was prepared with the composite technologies, and its formula was optimized; 3) through self-designed experiments the self-healing properties of the water- proofing agents was investigated; 4) the properties of the waterproofing agents were investigated and evaluated in accordance with the relevant standards.The core of the mechanism of circulating complexing crystallization– self-healing reaction for cracks is complexing agent can be cyclical reaction of complex crystallization, eventually resulting crystalline precipitate can fill pores and cracks. The complexing agent JS was prepared, and the analysis results of its working mechanism showed that: the complexing agent JS could cause a complexation reaction with Ca(OH)2, and generated instability precipitated calcium complexes; such calcium complexes could be converted to calcium silicate hydrate crystalline by further reaction with the silicate ion, meanwhile, JS was recovered so that it can work forever. The calcium silicate hydrate crystalline generated continuously filled pores and cracks, and could improve significantly the impermeability of the mortar, and endow the mortar with a self-healing function.The development of crystalline waterproofing agents should follow a complex technical routine. Throughing multiple orthogonal tests and single factor optimized tests, using complexing agent JS、active silica agent、organic waterproof agent、inorganic waterproof agent、water reducing agent and silica fume as raw material, a new type of cementitious capillary crystalline waterproofing agent with good water resistance and self-healing properties was successfully developed in the laboratory. The properties of self-made waterproofing agents were investigated in accordance with the National Standard GB 18445-2001.The test results indicated that: all performance indexes of them could conform to the specified standard; 275% impermeability pressure ratio(28 d) was obtained in self-made waterproofing agents; the second impermeability pressure(56 d) was 1.3 MPa, which was higher than the first.The water permeating and leaching processes of cracked cementitious specimens were investigated. The phase composition and microstructure of the precipitate on crack surface of cementitious specimens were studied by means of XRD and SEM. All the results showed that: owing to the dissolution and sedimentation of calcium hydroxide and the crystallization of calcium carbonate precipitation, exposed to water environment the autogenous healing of the cracks in the cementitious materials occurred, but the self-healing capabilities was quite limited. The self-healing capabilities of cement paste and mortar specimens mixed with self-made waterproofing agents were superior to the blank samples, and the former had a good secondary self-healing. Chemical reaction of self-made waterproofing agents occur to produce crystalline precipitates to fill the void, but also can accelerates the hydration process of cement, which generates C-S-H gel to block up the pores and cracks.更多还原