聚合物改性水泥基修补材料研究

【作者】 何凡；

【导师】 李益进；

【作者基本信息】 中南大学 ， 土木工程， 2011， 硕士

【摘要】 水泥混凝土路面因其强度高,耐久性优良,成为我国公路路面两大类型之一,由于国民经济的发展和交通量的急剧增加,水泥混凝土路面破损也日益严重,尤其是路面裂缝最为普遍,混凝土路面裂缝不仅仅影响路面工程的美观,还严重影响路面行车安全及舒适；因此,对水泥混凝土路面裂缝进行修补,具有重要的意义。结合国内外混凝土路面裂缝修补材料的研究进展,本课题通过聚合物乳液对水泥基材进行改性,来修补路面裂缝,以恢复路面使用功能。本文的主要研究内容与结论如下：1、首先采用正交试验,以5min粘度及7d抗压强度为控制指标,通过三因素四水平正交表,利用四种聚合物乳液SBR、EAV、CB、SD对水泥基材料改性,初选改性乳液。羧基丁苯胶乳SBR改性后的水泥基材料,其5min粘度最小,7d抗压强度最高,改性效果最佳。通过正交试验,确定修补材料的初始配合比,在性能研究的基础上优化其配合比。结果表明：水灰比为0.42～0.45,聚合物掺量为5%～20%时,改性净浆的粘度随着聚合物掺量的增加先增大后减小,随时间的延长逐渐增大。聚合物的掺入能有效改善水泥浆体的可灌性,但对改性浆体的凝结时间有滞缓作用。2、在优化修补材料配比的基础上,系统研究了聚合物掺量、水灰比等因素对性能的影响。研究表明：聚合物改性水泥砂浆的抗压强度随聚合物乳液掺量的增加而减小,抗折强度则先增大后减小。聚合物的加入能有效改善水泥砂浆的韧性,提高水泥砂浆的抗氯离子渗透性。3、聚合物的掺入能降低水泥砂浆的干缩。改性水泥砂浆与普通水泥砂浆干缩变化趋势相似,前期收缩较大,后期逐渐平缓。改性水泥砂浆的收缩随着聚合物掺量的增加先减小后增大,聚合物掺量为10%时,改性水泥砂浆的收缩最小。4、聚合物改性水泥净浆与水泥砂浆的粘结强度均高于普通水泥净浆与水泥砂浆,且随着聚合物掺量的增加均先增大后减小。当水灰比为0.42,聚合物掺量为10%时,改性浆体28d粘结强度较7d粘结强度增长达52%,同样比普通水泥浆体28d粘结强度提高达28%；对于改性水泥砂浆,聚合物掺量为5%～10%时,28d粘结强度较7d粘结强度增长了36%～38%,表明聚合物乳液能明显增加水泥基材料的粘结性能。5、研究了五种不同的养护方式对聚合物改性水泥砂浆强度的影响,结果表明：聚合物改性砂浆的水养护时间不宜过长。先水养护3d,然后在干燥条件下养护对强度发展最为有利。更多还原

【Abstract】 For high strength and good durability, cement concrete pavement has been one of two main types high way pavements in China. As a result of the national economys rapid development and the sharp growth of traffic volume, the breakage of centmet concrete pavement is in-creasingly serious, especially for the crack. The crack not merely affects the appearance of the pavement, but also the security and the comfortableness of driving. As a result, the repairing on cement concrete pavement is so significant in practice.By Studying the crack filling material in concrete pavement at home and abroad, this paper takes polymer emulsion to modify cement, to repair the cracks in pavement and restore the pavement features. The main research contents and conclusions of this paper are as follows:1. As the viscosity in 5min and compressive strength in 7d of crack filling material for controlling indicators, through orthogonal experiment, the paper at first selected the optimum modified cement-based material by three-factor and four-level from four Polymer emulsions:SRB、VAE、CB、SD. The results showed that:the best one was when cement modified with carboxylated SBR latex by orthogonal test, the viscosity in 5min was minimum and compressive strength in 7d maximum, and gotten the initial mixture proportion, based on the text of workability of the repair material to optimize the mixture proportion. The results showed that:The W/C was from 0.42 to 0.45 and the polymer content from 5% to 20%, the modified paste viscosity increased and then decreased with P/C increasing and increased with development of time. polymer emulsion could improve groutlbliity but stagnate the the setting time of modified paste. 2. Based on optimized mixture proportion of repair materials, this paper systematically studied the factors affecting the properties of repair material from polymer content,W/C and so on. The results showed that: the compressive strength of polymer modified mortar decreased with P/C increasing, the flexural strength at first rised and then decreased; and polymer emulsion could improve flexibility and resistance to chloride ion permeability of mortar.3. Polymer emulsion can decrease the contraction of cement mortar, polymer modified mortar’s shrinkage trends was similar to ordinary mortar, the pre-contraction was larger, and later steady, with increasing the polymer emulsion content, the contraction of modified mortar decreased first and then increased, when the P/C= 10%, the shrinkage of modified mortar was minimum.4. From the research of interfacial bond strength on repair materials, it reveals that:the interfacial bond strength of polymer modified cement paste and mortar were higher than ordinary cement paste and mortar, with the increasing of polymer content polymer modified cement and mortar’s interfacial bond strength increased first and then decreased. When the W/C=0.42, P/C=10%; the bond strength of modified cement paste increased up to 52% in 28d comparing with in 7d, up to 28% for reference cement paste in 28d; for modified mortar, when P/C increased from 5% to 10%, the bond strength in 28d increases from 36% to 38% than in 7d. It indicated that the polymer emulsion can improve the bonded performance of cement substrate significantly.5. Researched five different curing system for polymer modified cement mortar’s strength, the results showed that:the water-curing time of polymer modified mortar should not be too long, the best pre-conservation in water was 3d, the post-curing could be in dry conditions, so that it was best for the strength development of polymer modified mortar.更多还原