纤维增强高韧性水泥基材料设计与性能研究
发布时间：2018-09-15 06:09
【摘要】：现代建筑对建筑材料性能的要求越来越高,传统混凝土的发展由于其脆性大、韧性差的原因受到了很大的限制,混凝土的服役寿命和安全性问题日益突出。因此,研究高韧性水泥基材料,提高混凝土的柔韧性和弯曲变形能力,对于提高现代建筑结构的服役寿命和服役安全性具有重要的意义。本论文针对传统混凝土刚度大、柔韧性差的问题,开展丁苯乳液改性钢纤维混凝土、PVA纤维增强高韧性水泥基材料的制备技术、材料设计和性能研究。通过丁苯乳液、钢纤维的复合掺入来达到同时增加传统混凝土基体柔性、混凝土开裂后钢纤维与混凝土粘结强度的效果来达到增强混凝土韧性的目的,并通过扫描电镜、孔隙率测试等微观测试技术解释增韧原理;并从试验原材料性质出发,通过对原材料的预先处理、混合料搅拌工艺的选取,制备具有较高弯曲变形能力、能产生多缝开裂现象的PVA纤维增强高韧性水泥基材料,并评价不同配比水泥基材薄板和梁的弯曲韧性指数,观察裂纹的开裂形式;最后试验了两种高韧性水泥基材料复合使用的状态。得出以下结论:1、丁苯乳液能改善新拌混凝土、新拌钢纤维混凝土的工作性能;混凝土的抗压强度随着丁苯乳液掺量的增加而显著降低,但其抗折强度随着丁苯乳液的增加而提高;15%的丁苯乳液与1%的钢纤维复掺,能明显提高混凝土的抗折强度、抗冲击韧性以及弯曲韧性。2、显微硬度分析仪显示:15%的丁苯乳液改善了养护28d混凝土集料-浆体界面过渡区显微硬度;利用扫描电子显微镜观察了聚合物混凝土的微观结构,以及钢纤维从普通混凝土、聚合物混凝土中拔出后其表面形貌以及凹槽区微观形貌,结果表明:丁苯乳液在混凝土中交织成膜,增加了浆体、浆体-集料的致密性,增强了钢纤维与混凝土之间的界面粘结强度。3、丁苯乳液使混凝土分级进汞量波峰左移;在孔径为100nm-1000nm范围内的孔隙率提高;连续的聚合物网状膜结构连通较大的毛细孔,使大孔分割成封闭的小孔,在孔径大小10nm的凝胶孔区域范围内的凝胶孔孔隙率增大;空气养护下,由于干燥收缩出现大量裂纹,在大毛细孔即孔径100nm区域范围内,孔隙数量相对于标准养护时明显增加。4、选取粉煤灰做矿物掺合料,PVA纤维表面用硅油处理、纤维预分散处理的水泥基薄板能达到10.7mm的弯曲变形量,有明显的裂缝展开阶段,纤维的滑移是水泥基材获得变形能力的重要原因;掺入丁苯乳液的水泥基材料弯曲性能降低,板材厚度是决定弯曲变形量和裂缝形态的主要因素。5、PVA高韧性水泥基材料保护层能将内部普通混凝土的裂缝分散成许多微小的裂缝,两种材料复合使用具有良好的应用前景。
[Abstract]:Modern buildings require higher and higher performance of building materials. The development of traditional concrete is restricted because of its high brittleness and poor toughness. The service life and safety of concrete are becoming more and more serious. Therefore, it is of great significance to study high toughness cement-based materials and improve the flexibility and flexural deformation ability of concrete for improving the service life and safety of modern building structures. Aiming at the problems of high stiffness and poor flexibility of traditional concrete, the preparation technology, material design and properties of the modified steel fiber reinforced concrete (PVA) fiber reinforced by SBR emulsion were studied in this paper. The toughness of concrete was enhanced by adding the composite of steel fiber and butadiene emulsion to increase the flexibility of traditional concrete matrix and the bond strength of steel fiber and concrete after concrete cracking, and the toughness of concrete was enhanced by scanning electron microscope (SEM). The microcosmic testing techniques such as porosity test explain the toughening principle, and from the properties of the experimental raw materials, through the pre-treatment of the raw materials and the selection of the mixture mixing process, the preparation has the higher bending deformation ability. The PVA fiber reinforced high toughness cement-based material which can produce multi-joint cracking phenomenon was used to evaluate the flexural toughness index of the sheet and beam of cement base material with different proportions and to observe the crack form. Finally, two kinds of high toughness cement-based materials were tested. The following conclusions can be drawn: 1, butadiene emulsion can improve the working performance of fresh concrete and fresh steel fiber reinforced concrete, and the compressive strength of the concrete decreases significantly with the increase of the content of styrene butadiene emulsion. However, with the increase of butadiene-butadiene emulsion, the flexural strength of concrete is increased by 15% of butadiene emulsion and 1% of steel fiber, and the flexural strength of concrete can be improved obviously. The impact toughness and flexural toughness. 2. The microhardness analyzer showed that the microhardness of the transition zone between aggregate and slurry was improved by using 1: 15% butadiene emulsion, and the microstructure of polymer concrete was observed by scanning electron microscope (SEM). As well as the surface morphology of steel fiber extracted from ordinary concrete and polymer concrete, and the micro-morphology of grooves. The results show that butadiene emulsion interweaves into film in concrete, which increases the compactness of slurry, paste and aggregate. The interfacial bond strength between steel fiber and concrete is strengthened. 3. The styrene butadiene emulsion shifts the peak of mercury content in concrete to the left; the porosity increases in the range of pore size 100nm-1000nm; and the continuous polymer reticular membrane structure connects the larger capillary, The large pore is divided into a closed pore, and the porosity of the gel pore increases in the range of the gel pore area of the pore size 10nm. Under air curing, a large number of cracks occur due to the drying shrinkage, and in the large capillary area, that is, in the 100nm region of pore size, Compared with the standard curing condition, the number of pores is obviously increased .4.The surface of PVA fiber is treated with silicon oil by using fly ash as mineral admixture. The cement base sheet treated by fiber pre-dispersion can reach the bending deformation of 10.7mm and has obvious crack development stage. The slippage of the fiber is the important reason for the deformation ability of the cement substrate, and the flexural property of the cement-based material mixed with the butadiene emulsion is decreased. The thickness of plate is the main factor that determines the amount of bending deformation and the shape of crack. The protective layer of PVA high toughness cement-based material can disperse the cracks of common concrete into many tiny cracks. The composite use of the two kinds of materials has a good application prospect.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528
[Abstract]:Modern buildings require higher and higher performance of building materials. The development of traditional concrete is restricted because of its high brittleness and poor toughness. The service life and safety of concrete are becoming more and more serious. Therefore, it is of great significance to study high toughness cement-based materials and improve the flexibility and flexural deformation ability of concrete for improving the service life and safety of modern building structures. Aiming at the problems of high stiffness and poor flexibility of traditional concrete, the preparation technology, material design and properties of the modified steel fiber reinforced concrete (PVA) fiber reinforced by SBR emulsion were studied in this paper. The toughness of concrete was enhanced by adding the composite of steel fiber and butadiene emulsion to increase the flexibility of traditional concrete matrix and the bond strength of steel fiber and concrete after concrete cracking, and the toughness of concrete was enhanced by scanning electron microscope (SEM). The microcosmic testing techniques such as porosity test explain the toughening principle, and from the properties of the experimental raw materials, through the pre-treatment of the raw materials and the selection of the mixture mixing process, the preparation has the higher bending deformation ability. The PVA fiber reinforced high toughness cement-based material which can produce multi-joint cracking phenomenon was used to evaluate the flexural toughness index of the sheet and beam of cement base material with different proportions and to observe the crack form. Finally, two kinds of high toughness cement-based materials were tested. The following conclusions can be drawn: 1, butadiene emulsion can improve the working performance of fresh concrete and fresh steel fiber reinforced concrete, and the compressive strength of the concrete decreases significantly with the increase of the content of styrene butadiene emulsion. However, with the increase of butadiene-butadiene emulsion, the flexural strength of concrete is increased by 15% of butadiene emulsion and 1% of steel fiber, and the flexural strength of concrete can be improved obviously. The impact toughness and flexural toughness. 2. The microhardness analyzer showed that the microhardness of the transition zone between aggregate and slurry was improved by using 1: 15% butadiene emulsion, and the microstructure of polymer concrete was observed by scanning electron microscope (SEM). As well as the surface morphology of steel fiber extracted from ordinary concrete and polymer concrete, and the micro-morphology of grooves. The results show that butadiene emulsion interweaves into film in concrete, which increases the compactness of slurry, paste and aggregate. The interfacial bond strength between steel fiber and concrete is strengthened. 3. The styrene butadiene emulsion shifts the peak of mercury content in concrete to the left; the porosity increases in the range of pore size 100nm-1000nm; and the continuous polymer reticular membrane structure connects the larger capillary, The large pore is divided into a closed pore, and the porosity of the gel pore increases in the range of the gel pore area of the pore size 10nm. Under air curing, a large number of cracks occur due to the drying shrinkage, and in the large capillary area, that is, in the 100nm region of pore size, Compared with the standard curing condition, the number of pores is obviously increased .4.The surface of PVA fiber is treated with silicon oil by using fly ash as mineral admixture. The cement base sheet treated by fiber pre-dispersion can reach the bending deformation of 10.7mm and has obvious crack development stage. The slippage of the fiber is the important reason for the deformation ability of the cement substrate, and the flexural property of the cement-based material mixed with the butadiene emulsion is decreased. The thickness of plate is the main factor that determines the amount of bending deformation and the shape of crack. The protective layer of PVA high toughness cement-based material can disperse the cracks of common concrete into many tiny cracks. The composite use of the two kinds of materials has a good application prospect.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU528
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