复合型混凝土养护剂的制备及性能研究

发布时间：2018-03-18 07:44

本文选题：复合型养护剂　切入点：力学性能　出处：《长安大学》2014年硕士论文　论文类型：学位论文

【摘要】：充分合理的养护是提高混凝土耐久性的有效手段，养护剂养护作为一种新型养护方式具有高效、便捷、适应性强等诸多优点而受到越来越多的关注。但目前国内所研制的养护剂大多存在着养护机理单一、保水率低的缺点，且对养护剂的性能研究也仅局限于混凝土的力学及耐久性能，而针对养护剂的养护效果评价以及养护剂的微观作用机理研究较少。因此，研制一种高效多功能的复合型养护剂并开展相应研究具有重要意义。本文从养护剂各组成材料的作用机理出发，利用正交试验，系统分析了有机成膜组分、无机增密组分、改进组分对水泥砂浆保水性能及强度的影响，给出了复合型养护剂的最优配比，并对比研究了复合型养护剂与不同养护方式、不同种类养护剂对混凝土保水性能、力学性能、粘结性能、耐久性能的影响，同时利用表面吸水率法以及基于回弹强度的养护效率指数法对复合型养护剂的养护效果进行评价，最终通过XRD和SEM微观分析方法研究了养护剂的微观作用机理。研究结果表明：（1）以石蜡乳液为基础，复掺纯丙乳液、硅酸钠、三乙醇胺以及甲基硅醇钠，能够形成良好的有机/有机、有机/无机复合体系，发挥各组分的协同效应提高所制备的复合型养护剂的性能，3d有效保水率接近80%，28d抗压强度比达到95.5%。（2）复合型养护剂养护的混凝土试件其各龄期的抗压抗折强度均高于干燥养护对比试件，接近标准养护且略高于洒水养护。（3）复合型养护剂保水性能优于单一型养护剂，不同类型养护剂的性能差异较大，养护剂的最佳喷涂量应控制在250~300g/m2。（4）复合型养护剂克服了石蜡乳液对后浇混凝土粘结性能的影响，劈裂抗拉强度仅比一次性成型的标准养护试件低了0.27MPa。（5）复合型养护剂能够有效降低混凝土试件的干燥收缩，以及提高混凝土的抗渗、抗裂、耐磨性能，其中混凝土7d的干缩值降低了41.1%，28d渗水高度比为85.9%，3d裂纹数量和面积均低于干燥养护对比试件，裂纹降低率0.987，300g/m2喷涂量下混凝土磨耗量仅为1.96kg/m2。（6）表面吸水率法和养护效率指数CEI可以较好评价养护方法的养护效果，复合型养护剂养护试件3d表面吸水率为3.4×10-6cm2/s，，比对比试样降低了39.2%，养护龄期内养护剂养护试件CEI都大于干燥养护。（7）XRD和SEM结果显示复合型养护剂能够促进水泥的水化进程生成更多的水化产物，结晶粒径也更为粗大，且相互搭接形成密实结构。
[Abstract]:Adequate and reasonable curing is an effective means to improve the durability of concrete. As a new type of curing method, curing agent has high efficiency and convenience. Many advantages, such as strong adaptability, have attracted more and more attention. However, most of the curing agents developed in China have the disadvantages of single curing mechanism and low water retention rate. The performance of curing agent is limited to the mechanics and durability of concrete, but the evaluation of curing effect of curing agent and the microscopic mechanism of curing agent are few. It is of great significance to develop a compound curing agent with high efficiency and multi-function. Based on the action mechanism of curing agents, the effects of organic film forming components, inorganic thickening components and improved components on the water retention properties and strength of cement mortar were systematically analyzed by orthogonal test. The optimum ratio of compound curing agent is given, and the effects of compound curing agent and different curing ways, different curing agents on water retention, mechanical property, bond property and durability of concrete are compared. At the same time, the surface water absorption method and the curing efficiency index method based on springback strength were used to evaluate the curing effect of compound curing agent. Finally, the microcosmic mechanism of curing agent was studied by XRD and SEM microanalysis method. The results show that on the basis of paraffin emulsion, mixed with pure acrylic emulsion, sodium silicate, triethanolamine and sodium methylsilyl, a good organic / organic, organic / inorganic composite system can be formed. Exerting the synergistic effect of each component to improve the performance of the prepared compound curing agent the compressive strength ratio of concrete specimens cured with compound curing agent is higher than that of concrete specimens cured with compound curing agent in different ages. The effective water retention rate of 3 days is close to that of 80 and 28 days and the compressive strength ratio reaches 95.55.2.The concrete specimens cured with compound curing agents have higher compressive and flexural strength at different ages. Dry curing contrast specimen, The water retention performance of compound curing agent is better than that of single curing agent, and the performance of different curing agent is quite different. The optimum spraying amount of curing agent should be controlled at 250 ~ 300g / m ~ (2. 4)) compound curing agent can overcome the influence of paraffin emulsion on the bond property of post-cast concrete. The splitting tensile strength is only 0.27MPa. 5 lower than that of the one-off standard curing specimen. The composite curing agent can effectively reduce the dry shrinkage of concrete specimen and improve the impermeability, crack resistance and wear resistance of concrete. Among them, the dry shrinkage value of concrete for 7 days decreased by 41.1% and 28d water penetration height ratio was 85.9 days, the number and area of cracks were lower than those of dry curing specimens. The surface water absorption method and the maintenance efficiency index (CEI) can be used to evaluate the curing effect of the curing method. The crack reduction rate of 0.987g / m ~ 2 is only 1.96 kg / m ~ (2) for the sprayed concrete, and the surface water absorption method and the maintenance efficiency index (CEI) can be used to evaluate the curing effect of the method. The surface water absorbency of the composite curing sample was 3.4 脳 10 ~ (-6) cm ~ (-2) / s, which was 39.2% lower than that of the control sample. The CEI of the curing sample during curing period was higher than that of the dry curing sample. The results of SEM and SEM showed that the compound curing agent could promote the hydration of cement. Cheng Sheng became more hydrated products, The crystal size is also more coarse and overlapped with each other to form a dense structure.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU755.7

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