硫铝酸盐水泥基胶凝材料的研究

发布时间：2018-05-14 07:19

  本文选题：硫铝酸盐水泥 + 低成本　； 参考：《武汉理工大学》2015年硕士论文

【摘要】：硫铝酸盐水泥具有凝结时间短、早强高强、高抗渗、良好耐久性等优点,基于原材料的限制,硫铝酸盐水泥成本较硅酸盐水泥高,凝结时间不易控制,掺合料引入到硫铝酸盐水泥中易降低其力学、抗渗等性能,限制了其推广使用。论文依托国家自然科学基金项目(51178363),通过大掺量引入矿物掺合料(粉煤灰、矿粉),降低硫铝酸盐水泥的成本,使其达到一定的经济效益(掺合料掺量达40%),研究不同掺合料对硫铝酸盐水泥基本工作性能、力学性能、干缩的影响。根据化学激发效应、超细粉体效应、结晶诱导效应、外加剂调节、优势互补原理等对低成本硫铝酸盐水泥基胶凝材料进行改性,综合考虑基本工作性能、力学性能、微观性能、耐久性能等,调配出最佳改性配比,使体系成本降低的同时,性能得到提高。其中,化学激发是最重要的改性方法,论文中把抗压强度作为改性效果最重要指标。主要研究结果如下:1、矿粉、硅灰对硫铝酸盐水泥凝结时间作用效果较小,粉煤灰具有一定的缓凝作用;粉煤灰与矿粉对硫铝酸盐水泥的标稠用水量及流动度具有积极作用,硅灰掺量少于5%时,具有积极作用;引入粉煤灰与矿粉后,硫铝酸盐水泥各龄期抗折、抗压强度均降低,当硅灰掺量不超过5%时,对抗压强度具有促进作用;三种掺合料对硫铝酸盐水泥的干缩均具有明显的抑制作用。2、筛选出一种改性效果较好的碱性激发剂M,引入M后,体系2h、3d、7d、28d、1年抗压强度最高分别提高了134%、93%、62%、61%、63%。M促进了硫铝酸盐水泥体系早期钙矾石及凝胶的生成,使其具有较高的早期强度,激发了粉煤灰的活性,使其参与水泥的后续水化,提高了浆体密实度。M可能易使钙矾石早期结晶程度变差,当累积至7d时,易出现强度倒缩,随养护时间延长,这种现象消失。3、与体系相容性排序依次是聚羧酸KH-5减水剂KH-6减水剂氨基磺酸系减水剂萘系减水剂。对粉煤灰-硫铝酸盐水泥体系强度影响排序依次是纳米二氧化硅(1%-2%)超细碳酸钙(1%-3%)硅灰(≤10%),正交试验表明对矿粉-粉煤灰-硫铝酸盐水泥强度影响排序依次是激发剂硅灰超细碳酸钙,最佳掺量分别为4%、6%、3%。4、矿粉与粉煤灰以2:1复合比单掺粉煤灰的效果好,体系2h、3d、7d、28d、90d抗压强度分别提高7%、16%、23.7%、20%、40%;确定最佳组分及改性配比后,粉煤灰组2h、3d、7d、28d、90d抗压强度分别提高了17.5%、42.8%、51.8%、61.0%、66.7%,矿粉与粉煤灰复合组分别提高了12.3%、14.8%、13.8%、26%、15.4%。在20%浓度硫酸钠、20%浓度氯化钠溶液中侵蚀90d后,各组抗压强度不但没有降低,反而有不同程度的提高,矿粉-粉煤灰-硫铝酸盐水泥组提高的最明显。
[Abstract]:Sulphoaluminate cement has the advantages of short setting time, early strength and high strength, high impermeability, good durability and so on. Due to the limitation of raw materials, the cost of sulphoaluminate cement is higher than that of Portland cement, and the setting time is not easy to control. It is easy to reduce mechanical and impermeable properties of sulphoaluminate cement by introducing admixture, which limits its popularization and application. Based on the project of National Natural Science Foundation of China 51178363, the paper introduces mineral admixture (fly ash, mineral powder) to reduce the cost of sulphoaluminate cement by introducing large amount of mineral admixture (fly ash, mineral powder). The effects of different admixtures on the basic working properties, mechanical properties and dry shrinkage of sulphoaluminate cement were studied. According to the chemical excitation effect, ultrafine powder effect, crystallization induction effect, admixture adjustment, advantage complementary principle and so on, the low cost sulphoaluminate cement based cementitious materials were modified, and the basic working properties, mechanical properties and microscopic properties were considered synthetically. The best ratio of modification was prepared, so that the cost of the system was reduced, and the performance was improved at the same time. Among them, chemical excitation is the most important modification method, and the compressive strength is regarded as the most important index of modification effect in this paper. The main results are as follows: (1) the effect of mineral powder and silica fume on the setting time of sulphoaluminate cement is small, the fly ash has a certain retarding effect, and the fly ash and mineral powder have a positive effect on the standard water consumption and fluidity of sulphoaluminate cement. When the amount of silica fume is less than 5, it has a positive effect, when fly ash and mineral powder are introduced, the compressive strength of sulphoaluminate cement decreases in every age, and when the amount of silica fume is less than 5, it can promote the compressive strength of sulphoaluminate cement. The dry shrinkage of sulphoaluminate cement was inhibited obviously by the three admixtures. The maximum compressive strength of the system was 134kW / 62and 62D / 28d, respectively, which promoted the formation of ettringite and gel in the early stage of sulphoaluminate cement system, made it have higher early strength, stimulated the activity of fly ash, and made it participate in the subsequent hydration of cement. The increase of slurry compactness. M may make the early crystallization degree of ettringite worse, and when it accumulates to 7 days, the strength will shrink easily, and the curing time will be prolonged. The order of compatibility with the system is polycarboxylic acid KH-5 water reducer, KH-6 water reducer, amino sulfonic acid superplasticizer, naphthalene series water reducer. The order of influence on the strength of fly ash-sulphoaluminate cement system is nanometer silica 1- 2) ultrafine calcium carbonate and 1-3) silica fume (鈮，

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