超早强硫铝酸盐水泥基材料研究与应用

发布时间：2019-05-26 18:45

【摘要】：随着社会经济的不断进步,对现有工程和新建工程的要求愈来愈高,普通混凝土已经难以满足一些工程对材料的特殊要求。如铁路、高架桥梁、军事工程和重大基础建设等工程要求某些部位的材料能够在较短的时间内获得较高的力学性能,并且易于施工。针对这种情况,本文依托济青高速改扩建工程,选用硫铝酸盐水泥结合自主研制的专用复合外加剂制备了一种超早强硫铝酸盐水泥基材料。该材料环保节能,施工方便,具有流动性好、凝节时间适中、早期强度高、与普通硅酸盐混凝土粘结性能强、抗冻性好、耐硫酸盐侵蚀性强等特点,适用于公路桥梁等工程的维修加固和对材料有早强要求的工程。为硫铝酸盐水泥在特殊胶凝材料领域的研究和应用提供参考。本文首先研配了硫铝酸盐水泥专用复合外加剂。通过对甲酸钙、碳酸锂和硫酸铝等在硫铝酸盐水泥水化反应中的促凝机理研究和试验,配制了硫铝酸盐水泥专用复合早强剂(ICCH),ICCH能够显著提高水泥的小时强度,并对长期强度无不利影响。为延缓水泥凝结,确保足够的操作时间,利用硼酸、纤维素醚等研配了水泥专用复合缓凝剂(BS),BS能够稳定有效的延缓硫铝酸盐水泥凝结时间。通过自主研配的硫铝酸盐水泥专用复合外加剂配制出了超早强硫铝酸水泥净浆、砂浆和混凝土。水泥净浆初始流动度大于200mm,初凝时间约20min,4h抗压强度达到46.64MPa,最终强度超过70MPa;砂浆流动性良好,依据相关标准取消振动进行测试的流动度大于250mm;保持工作性时间约30min,2h抗压强度超过30MPa,4h抗压强度达到43.7MPa,1d抗压强度超过50MPa,后期强度稳定增长;混凝土保持工作性时间超过40min,4h抗压强度不低于40MPa,7d抗压强度超过50MPa,抗折强度在4h后均不小于6.5MPa。研究了超早强硫铝酸盐水泥基材料的早期特性和耐久性。试验证明,该材料具有较好的早期抗裂性,并且体积最终不发生收缩;其能够与硅酸盐水泥基材料和自身材料很好的粘结,自身粘结的抗折强度在1d后不低于6MPa;该材料具有优异的抗冻性能,在250次冻融循环后,抗压强度仍保持40MPa以上;其耐硫酸盐侵蚀性能优良,在饱和硫酸钠溶液中浸泡90d后,抗压强度最低值超过40MPa,抗折强度大于10MPa。本文研配的超早强硫铝酸盐水泥于2016年8月和11月提前在甘肃桥梁维修加固项目上应用,能够确保4h达到通车要求,大大缩短了工期,取得了良好效果。将于2017年11月用于济青高速改扩建工程。
[Abstract]:With the continuous progress of social economy, the requirements for existing and new projects are getting higher and higher, and ordinary concrete has been difficult to meet the special requirements of some projects for materials. For example, railways, viaducts, military projects and major infrastructure projects require that materials in certain parts can obtain higher mechanical properties in a relatively short period of time, and are easy to construct. In view of this situation, based on the Jiqing high speed reconstruction and expansion project, a super early strength sulphoaluminate cement based material was prepared by using sulphoaluminates cement combined with a special compound admixture developed by ourselves. The material has the advantages of environmental protection and energy saving, convenient construction, good mobility, moderate setting time, high early strength, strong bond performance with ordinary silicate concrete, good frost resistance, strong sulfate corrosion resistance and so on. It is suitable for maintenance and reinforcement of highway and bridge projects and projects with early strength requirements for materials. It provides a reference for the research and application of sulphoaluminate cement in the field of special cementitious materials. In this paper, a special compound admixture for sulphoaluminate cement was developed. Through the study and test on the coagulation promoting mechanism of calcium formate, lithium carbonate and aluminum sulfate in the hydration reaction of sulphoaluminate cement, the special compound early strength agent (ICCH), ICCH for sulphoaluminate cement was prepared, which can significantly improve the hourly strength of cement. And has no adverse effect on the long-term strength. In order to delay the setting of cement and ensure enough operation time, (BS), BS, a special compound retarder for cement, was developed by using boric acid and cellulose ether to delay the setting time of sulphoaluminate cement stably and effectively. The super early strength sulphoalicylic acid cement paste, mortar and concrete were prepared by using the special compound admixture of sulphoaluminate cement developed by ourselves. The initial mobility of cement paste is more than 200 mm, the initial setting time is about 20 min, the compressive strength of 4 h is 46.64 MPA, and the final strength is more than 70 MPA, and the mobility of mortar is good, and the mobility of mortar is more than 250 mm according to the relevant standards. When the working time was kept for about 30 min, the 2 h compressive strength exceeded 30 MPA, the 4 h compressive strength reached 43.7 MPA, the 1 d compressive strength exceeded 50 MPA, and the strength increased steadily at the later stage. The working time of concrete is more than 40 min, the compressive strength of 4 h is not less than 40 MPA, the 7 d compressive strength is more than 50 MPA, and the bending strength is not less than 6.5 MPA after 4 h. The early characteristics and durability of super early strength sulphoaluminate cement based materials were studied. The experimental results show that the material has good early crack resistance, and the volume does not shrink at last, and it can bond well with silicate cement-based material and its own material, and the bending strength of self-bonding material is not less than 6 MPA after 1 day. The material has excellent frost resistance, and the compressive strength is still above 40MPa after 250 freeze-thaw cycles. After soaking in saturated sodium sulfate solution for 90 days, the lowest compressive strength is more than 40 MPA, and the bending strength is more than 10 MPA. The super early strong sulphoaluminate cement developed in this paper was applied to Gansu bridge maintenance and reinforcement project in August and November 2016 in advance, which can ensure that the opening requirement of 4 hours can be met, the construction period has been greatly shortened, and good results have been obtained. It will be used for the reconstruction and expansion of Jiqing Expressway in November 2017.
【学位授予单位】：烟台大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU528

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