增效剂CTF与不同类型减水剂复掺对水泥基材料性能影响的研究

发布时间：2018-06-09 06:15

本文选题：增效剂CTF + 减水剂　；参考：《广西大学》2014年硕士论文

【摘要】：研究了新型混凝土外加剂增效剂CTF与聚羧酸系(PCE)、萘系(FDN)、脂肪族(FAS)三种不同类型减水剂的有效复掺对水泥基材料性能的影响,并分析其作用机理；在外加剂复掺的基础上,研究了常用矿物掺合料(粉煤灰、矿粉)与石灰石粉的多元复掺对混凝土性能的影响。主要研究内容和结果如下：采用净浆初始流动性、流动性经时损失、浆体保水性、砂浆工作性以及胶砂强度等几个常用指标全面评价了CTF和不同减水剂复掺与水泥的相容性问题,确定了CTF与减水剂复掺使用的可行性。通过配制0.35和0.50两个水胶比系列的混凝土,在不减少和减少10%基准水泥用量的情况下,研究了CTF与减水剂复掺对混凝土强度的影响规律；结果表明：CTF的掺入可以在有效降低基准水泥用量的同时提高混凝土的强度,CTF对混凝土强度的促进作用主要集中在中后期。通过测试水泥非常早期水化热、水泥悬浮液电导率和水泥净浆不同龄期的化学结合水量,研究了外加剂对水泥水化历程的影响,并分析了水泥与外加剂的相互作用机理。结果表明：CTF和PCE减水剂促进了第一放热峰值的增加,FDN和FAS减水剂降低了第一放热峰值,CTF与三种减水剂均不同程度地促进了前45min累积放热量的增加；CTF的掺入,促进了水泥水化的离子溶出,增大了水泥悬浮液电导率,而三种减水剂则由于其本身电离的离子与水泥水化溶出的离子发生络合反应,降低了水泥悬浮液的电导率；CTF与三种减水剂复掺均不同程度地提高了水泥水化样品中后期的化学结合水量。研究了石灰石粉、粉煤灰、矿粉的多元复掺以及CTF的掺入对混凝土工作性能、强度、耐久性能和微观孔结构的影响,并对掺合料混凝土孔结构参数与抗氯离子渗透性能、抗碳化性能进行了相关性分析。结果表明：在适宜掺量下,石灰石粉等量取代矿粉或粉煤灰,可以有效地改善混凝土的工作性能,且对强度影响不大,但石灰石粉的掺入使得混凝土孔结构粗化,不利于混凝土的抗氯离子和抗碳化性能；CTF的掺入改善了掺合料混凝土的和易性和孔结构,提高了强度和耐久性能；掺合料混凝土的孔隙率和平均孔径与抗氯离子渗透性能、抗碳化性能均有不同程度的关联,其中,在水胶比相同的情况下,无论混凝土的组成如何,孔隙率与混凝土抗碳化性能的相关程度很高,二次多项式相关系数高达0.9533。
[Abstract]:The effect of effective admixture of three different types of water-reducing agents, CTF, polycarboxylic acid series PCEC, naphthalene and aliphatic group FAS, on the properties of cement-based materials was studied, and the mechanism of the effects of CTF on the properties of cement-based materials was analyzed. The effect of mineral admixture (fly ash, mineral powder) and limestone powder on concrete properties was studied. The main contents and results are as follows: the initial fluidity of the pulp, the loss of the fluidity in time, and the water retention of the pulp. The compatibility of CTF and different superplasticizer with cement was comprehensively evaluated by several common indexes, such as the workability of mortar and the strength of cement. The feasibility of compound use of CTF and water reducer was determined. The effect of CTF and superplasticizer on the strength of concrete was studied by preparing two series of concrete with water binder ratio of 0.35 and 0.50 without reducing and reducing the dosage of 10% standard cement. The results show that the incorporation of% CTF can effectively reduce the amount of reference cement and increase the strength of concrete. The effect of CTF on the strength of concrete is mainly concentrated in the middle and late stage. The hydration heat of cement is tested in very early stage. The influence of admixture on cement hydration history was studied and the interaction mechanism between cement and admixture was analyzed. The results showed that the increase of the first exothermic peak value was promoted by the water reducing agent of 1: CTF and PCE. The first exothermic peak value was decreased by FDN and FAS superplasticizer. Both CTF and three water reducers promoted the increase of cumulative heat release of 45min in different degrees. It promotes the ion dissolution of cement hydration, increases the conductivity of cement suspension, and the three kinds of water reducer react with the ions of cement hydration because of their ionization ions. The conductivity of cement suspensions and the addition of CTF and three water reducers increased the chemical binding water of cement hydration samples in different degrees. The limestone powder, fly ash, lime stone powder and fly ash were studied. The effects of multicomponent addition of mineral powder and CTF on the performance, strength, durability and microstructure of concrete are discussed. The correlation between pore structure parameters and chloride ion permeation resistance and carbonation resistance of concrete admixtures is analyzed. The results show that the lime stone powder can effectively improve the working performance of concrete and has little effect on the strength of concrete, but the limestone powder can coarsening the pore structure of concrete by replacing the mineral powder or fly ash with the same amount of limestone powder. The incorporation of CTF improves the easiness and pore structure of admixture concrete, improves the strength and durability of concrete, and improves the porosity, average pore size and chloride ion permeability of admixture concrete. In the case of the same water-binder ratio, the correlation between porosity and carbonation resistance of concrete is very high, and the correlation coefficient of quadratic polynomial is 0.9533.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU528.042.2

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