【作者】 刘鹏；

【导师】 卢爽；

【作者基本信息】 哈尔滨工业大学 ， 建筑与土木工程（专业学位）， 2018， 硕士

【摘要】 蒸养混凝土抗硫酸盐-氯盐复合侵蚀性能及其机理目前尚未研究清楚,本文优化了具有良好抗硫酸盐侵蚀性能的蒸养工艺参数,并研究了不同掺合料的蒸养混凝土在硫酸盐-氯盐混合溶液侵蚀时,相关离子的扩散规律以及混凝土的基本力学性能,探究蒸养混凝土的侵蚀损伤演变规律,并得到最优的掺合料配比,最终制定出一套混凝土配制技术方案,为对抗硫酸盐和氯盐侵蚀性能要求较高地区的混凝土的材料选择、设计提供技术参数和依据。主要进行了如下工作:通过改变砂浆的蒸养工艺参数:静停时间(1h~6h)、恒温时间(1h~6h)和恒温温度(50℃~90℃),测试砂浆在不同龄期时的抗压耐蚀系数变化,并结合压汞测试对孔隙结构进行分析,得到了基于抗硫酸盐侵蚀性能提升的蒸养工艺参数。在此基础上,向砂浆中掺加不同种类和掺量的掺合料(15%~35%粉煤灰,5%~15%硅灰,5%~15%偏高岭土,5%~15%LDH),对砂浆进行优化后的蒸养工艺处理,测试其不同龄期时的抗压耐蚀系数的变化,结合压汞测试和XRD测试手段对其进行微观分析,比较不同种类及掺量的掺合料对胶凝体系的抗硫酸盐侵蚀性能的影响,得到了基于抗硫酸盐侵蚀性能提升的掺合料种类及配比。在已得到的掺合料种类、配比和蒸养工艺参数的基础上,对混凝土进行复掺掺合料处理并进行蒸养养护。对混凝土进行干湿循环试验,在不同龄期时对混凝土的抗压强度、质量、动弹模量进行测试,通过XRD、SEM、压汞、工业CT和离子滴定等手段阐述分析其性能变化机理,探究了蒸养混凝土在复合溶液侵蚀下的耐久性变化规律,最终得出了抗硫酸盐-氯盐复合侵蚀效果最好的掺合料配比,并提出了能够应用于抗硫酸盐-氯盐侵蚀性能要求较高的地区的混凝土生产评价指标。最后,对混凝土复合侵蚀过程进行假定(认为损伤过程是一个衰变的过程),在牛顿冷却定律的基础上对混凝土的损伤过程进行计算、分析,并结合试验结果建立了三指标(抗压耐蚀系数、相对动弹性模量以及质量变化率)两影响因素(粉煤灰和硅灰掺量和干湿循环次数)损伤模型,也就是混凝土的寿命预测方程。更多还原

【Abstract】 The corrosion resistance and mechanism of steam cured concrete to sulfate-chloride compound corrosion have not been studied yet,in this paper,the parameters of steam curing process with good resistance to sulfate attack were optimized,and the diffusion law of related ions and the basic mechanical properties of concrete of steamed concrete with different admixtures in the case of sulfate-chlorine mixed solution erosion were studied.Investigate the evolution law of erosion damage of steamed concrete,and obtain the optimal blending ratio.Finally,a set of concrete preparation technical schemes is developed to select materials for concrete in areas with high requirements for sulfate and chloride corrosion resistance.The design provides technical parameters and basis.The main conclusions are as follows:By changing the steam curing parameters of mortar: static stop time(1h~6h),constant temperature time(1h~6h)and constant temperature(50 ~90 C),the changes of compressive and corrosion resistance coefficients of mortar at different ages were tested.The pore structure was analyzed by mercury intrusion test,and the steam curing parameters based on the improvement of sulfate corrosion resistance were obtained.On this basis,different kinds and dosages of admixtures(15%~35% fly ash,5%~15% silica fume,5%~15% metakaolin,5%~15% LDH)were added to the mortar to optimize the autoclave curing process.The changes of compressive and corrosion resistance coefficients of the mortar at different ages were tested and compared by mercury intrusion test and XRD test.The effects of different kinds and dosages of admixtures on the sulfate corrosion resistance of cementitious system were studied.The kinds and proportion of admixtures based on the improvement of sulfate corrosion resistance were obtained.On the basis of the types,proportions and steam curing parameters of the admixtures,the concrete was treated with compound admixtures and cured by steam.The dry-wet cycling test of concrete is carried out,and the compressive strength,quality and dynamic elastic modulus of concrete are tested when the concrete reaches its age.The mechanism of performance change is elaborated and analyzed by means of XRD,SEM,mercury injection,industrial CT and ion titration.The law of durability change of steam cured concrete under the erosion of composite solution is explored.Finally,the effect of sulfate-chloride compound corrosion resistance is obtained.Good admixture ratio and concrete production evaluation index which can be applied to areas with high sulfate-chloride corrosion resistance requirements are put forward.Finally,assuming that the damage process of concrete is a decay process,thedamage process of concrete is calculated and analyzed on the basis of Newton’s cooling law.Based on the test results,two influencing factors(fly ash and silica fume content and wet-dry cycle)are established,which are three indexes(compressive corrosion resistance coefficient,relative dynamic elastic modulus and mass change rate).Damage model,that is,life prediction equation of concrete.更多还原