既有结构混凝土表面强化材料耐久性试验研究

发布时间：2018-03-28 01:19

本文选题：聚脲弹性体　切入点：丙乳砂浆　出处：《南京航空航天大学》2016年硕士论文

【摘要】：随着我国基础设施建设的迅猛发展,钢筋混凝土结构已经普遍使用于桥梁工程、水利水电工程、港口航道与海岸工程等。但在水工环境下,钢筋混凝土结构耐久性问题日益突出。一方面受高速含沙水流冲刷,混凝土表面会遭受较严重的磨损,造成钢筋保护层减小;另一方面由于水中氯盐侵蚀,混凝土中的钢筋易发生锈蚀,造成混凝土结构出现锈胀裂缝,表层剥落。若不及时维修,如此恶性循环则会大大降低钢筋混凝土结构的承载力和使用寿命。本课题通过试验综合分析了聚脲弹性有机材料、丙乳砂浆和环氧砂浆的抗冲磨、抗氯离子渗透及抗碳化性能,并研究了矿渣微粉和粉煤灰分别等量取代水泥掺量的36%以内时,对丙乳砂浆的耐久性提升效果,最后通过工程实例验证了改性丙乳砂浆的可行性。本课题所得到结论如下:(1)聚脲材料由于自身优异的弹性体有机材料特性,其抗冲磨性、抗氯离子渗透性及抗碳化性均远远优于丙乳砂浆、环氧砂浆等水泥基材料。(2)随着矿渣掺量的增加,丙乳砂浆的抗压、抗折和抗冲磨强度均呈先增加后降低的趋势,最佳掺量范围在6%～12%;矿渣掺量在9%附近时,抗冲磨强度可提高约18%;随矿渣掺量的增加,改性丙乳砂浆的氯离子渗透系数呈线性降低的趋势,掺量在36%时,其氯离子渗透系数降低约59%;(3)随着粉煤灰掺量的增加,丙乳砂浆的抗压、抗折强度、粘结抗折强度和抗碳化性均呈线性降低的趋势;抗冲磨强度呈先增加后降低的趋势,粉煤灰最佳掺量在6%附近,抗冲磨强度提高约12%;丙乳砂浆的氯离子渗透系数呈先降低而后增加的趋势,粉煤灰掺量不宜超过18%。(4)同掺量条件下,矿渣改性丙乳砂浆的耐久性能优于粉煤灰改性丙乳砂浆,根据工程要求,若需获得较高的力学性能、抗冲磨性及抗碳化性,矿渣掺量建议在6%～12%;若仅考虑抗氯离子渗透性能,掺量建议在36%。
[Abstract]:With the rapid development of infrastructure construction in China, reinforced concrete structures have been widely used in bridge engineering, water conservancy and hydropower engineering, port waterway and coastal engineering, etc. The durability problem of reinforced concrete structure is becoming more and more serious. On the one hand, the surface of concrete will suffer more serious wear, resulting in the decrease of the protective layer of steel bar; on the other hand, because of chlorine salt erosion in water, the concrete surface will suffer more serious wear and tear. Steel bars in concrete are prone to rust, resulting in corrosion cracks in the concrete structure, surface exfoliation. If not repaired in time, This vicious circle will greatly reduce the bearing capacity and service life of reinforced concrete structures. This paper comprehensively analyzes the impact and wear resistance, chloride ion penetration resistance and carbonation resistance of polyurea elastic organic materials, acrylic emulsion mortar and epoxy mortar. The effects of slag powder and fly ash on the durability of acrylic emulsion mortar were studied when the cement content was replaced by the same amount of slag powder and fly ash respectively within 36% of the cement content. Finally, the feasibility of modified acrylic emulsion mortar is verified by an engineering example. The conclusion of this paper is as follows: 1) the impact and wear resistance of polyurea material is due to its excellent properties of elastomer organic materials. The penetration resistance and carbonation resistance of acrylic emulsion mortar are much better than those of acrylic emulsion mortar. With the increase of slag content, the compressive strength, flexural strength and impact wear resistance of acrylic emulsion mortar increase first and then decrease with the increase of slag content. When the slag content is about 9%, the impact and wear strength can be increased by about 18%. With the increase of slag content, the chloride permeation coefficient of modified acrylic emulsion mortar tends to decrease linearly, and when the content of slag is about 9%, the chloride ion permeability coefficient of modified acrylic emulsion mortar decreases linearly, and when the slag content is about 9%, the chloride ion permeability coefficient of the modified acrylic emulsion mortar decreases linearly with the increase of slag content. With the increase of the content of fly ash, the compressive strength, flexural strength, bond flexural strength and carbonation resistance of acrylic emulsion mortar decreased linearly, and the impact wear strength increased first and then decreased. The best content of fly ash is about 6%, the strength of abrasion resistance is increased by 12%, the permeability coefficient of chloride ion of acrylic emulsion mortar decreases first and then increases, and the content of fly ash should not exceed 18%. The durability of slag modified acrylic emulsion mortar is better than that of fly ash modified acrylic emulsion mortar. According to the engineering requirements, if we need to obtain higher mechanical properties, abrasion resistance and carbonation resistance, the slag content is suggested to be at 6 / 12. The dosage is suggested at 36.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TV431

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