快凝快硬高强混凝土的制备与性能

发布时间：2018-03-13 12:06

本文选题：快凝快硬高强混凝土　切入点：超早强剂　出处：《重庆大学》2014年硕士论文　论文类型：学位论文

【摘要】：早强、超早强混凝土具有凝结时间短、早期强度高且耐久性良好等特点而广泛用于混凝土路面、机场跑道等需要快速修补的工程以及海港码头、桥梁隧道等快速抢修抢建工程。传统的配制方法是采用特种水泥或特殊工艺，制备的混凝土通常后期强度倒缩严重，同时由于原材料价格昂贵、工艺复杂等原因而不适于工程推广应用。本课题旨在采用常规原材料及普通工艺，研制出凝结时间适宜施工、早期强度高、长期强度不倒缩且耐久性良好的混凝土。本试验以超早强混凝土制备技术和高强混凝土制备技术为基础，提出了利用42.5R普通硅酸盐水泥掺适量的硅灰，加入自行配制的由快凝早强组分和减水组分组成的超早强剂，制备出快凝快硬高强混凝土的新途径。采用常规的原材料及通用的工艺方法(强制搅拌+振动密实)，制备出初凝时间不小于30min，终凝时间不大于60min，6h抗压强度10MPa，抗折强度1.5MPa，1d抗压强度40MPa，抗折强度5MPa，28d抗压强度80MPa，，抗折强度10MPa的快凝快硬高强混凝土。同时，研究了快凝早强组分对水泥净浆凝结时间的影响；胶凝材料总量、硅灰掺量、减水组分种类、快凝早强组分掺量及内部组分比、水胶比等对混凝土凝结时间和早期强度的影响。分别利用快速冻融循环试验和硫酸盐干湿循环试验研究了所制备快凝快硬高强混凝土的抗冻性能和抗硫酸盐侵蚀性能。结果表明：经历500次快速冻融循环后，混凝土质量损失率未超过2%，抗压强度损失率未超过15%；经历120次硫酸盐干湿循环后，混凝土质量不但未损失反而增大，相对抗蚀系数未低于75%。故而本试验所制备混凝土抗冻性能和抗硫酸盐侵蚀性能良好。通过XRD和TG-DSC分析，研究了本试验所用自制超早强剂对水泥水化硬化过程的影响，从而从微观层面解释本试验用自制超早强剂的快凝早强机理。
[Abstract]:Early strength, super early strength concrete has the characteristics of short setting time, high early strength and good durability, and it is widely used in concrete pavement, airport runway and other projects requiring rapid repair, as well as harbor wharf. The traditional preparation method is to adopt special cement or special technology. The concrete prepared usually has a severe shrinkage in later stage, and because of the high price of raw materials, The purpose of this project is to develop concrete with suitable setting time, high early strength, long term strength and good durability by using conventional raw materials and common technology. On the basis of ultra-early strength concrete preparation technology and high strength concrete preparation technology, this paper puts forward that 42.5R ordinary Portland cement is mixed with proper amount of silica fume, and a self-made super early strength agent consisting of fast setting early strength component and water reducing component is added. A new way to produce fast solidification and fast hardening high strength concrete is presented. The initial setting time is not less than 30 min, the final setting time is not more than 60 min or 6 h compressive strength 10 MPA, and the bending resistance is not less than 10 MPA using conventional raw materials and general process (forced agitation vibration compaction). The compressive strength is 1.5 MPA / 1 d, the compressive strength is 40 MPA, the flexural strength is 5 MPA / 28 days, the compressive strength is 80 MPA and the flexural strength is 10 MPA. The effects of early strength components on the setting time of cement paste, the total amount of cementitious materials, the content of silica fume, the types of water reducing components, the content of early strength components, the ratio of internal components and the ratio of water to binder on the setting time and early strength of concrete were studied. The freeze resistance and sulfate corrosion resistance of fast solidified fast hardening high strength concrete were studied by rapid freeze-thaw cycle test and sulphate dry wet cycle test respectively. The results showed that the rapid freeze-thaw cycle experienced 500 rapid freeze-thaw cycles. The mass loss rate of concrete is not more than 2 and the loss rate of compressive strength is not more than 15. After 120 sulphate dry and wet cycles, the quality of concrete not only increases, but also does not lose. The corrosion coefficient of phase resistance is not lower than 75. Therefore, the frost resistance and sulfate corrosion resistance of concrete prepared in this experiment are good. By means of XRD and TG-DSC analysis, the effect of the self-made super early strength agent on the hydration and hardening process of cement was studied, and the mechanism of quick solidification and early strength of the self-made super early strength agent was explained from the microscopic level.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528

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