本文選題：PVA-SHCC + 溫度作用�。� 參考：《青島理工大學》2013年碩士論文

【摘要】：火災、地震、甚至環(huán)境潮濕等是加速鋼筋混凝土結構劣化的主要因素，嚴重影響整體結構的耐久性和安全性，因此結構在使用壽命周期內(nèi)需要進行維護、修復和加固。傳統(tǒng)水泥基材料由于自身脆性、抗拉強度低、易開裂等缺點限制了其發(fā)展，而隨著現(xiàn)代土木工程向大跨度、輕型、高聳結構和地下、海洋中的發(fā)展，工程結構對修復材料性能的要求也越來越高。聚乙烯醇纖維增強應變硬化水泥基復合材料（PVA-SHCC：PolyvinylAlcohol Fiber Reinforced Strain-Hardening Cementitious Composites）具有高韌性、應變硬化和多微裂縫破壞特征、高能量耗散性等特點，將其應用于我國的重大工程建設、結構耐久性防護或已有受損部位的修復加固，對提高結構的耐久性和抗震性具有重要意義。 本文通過抗折強度試驗、抗壓強度試驗、三點彎曲試驗、四點彎曲試驗和毛細吸水試驗研究了高溫、內(nèi)摻型防水處理與否對PVA-SHCC抗折強度、抗壓強度、抗彎承載能力、變形能力、能量吸收能力、彎曲韌性和抗?jié)B性能的影響，并與未摻加PVA纖維的基準試件進行了對比。力學性能試驗結果表明，摻加PVA纖維能顯著提高SHCC的抗折強度、抗彎能力、變形能力、能量吸收能力和彎曲韌性，一定程度提高SHCC的抗壓強度；PVA纖維的引入改變了SHCC的彎曲破壞形態(tài)，與基準試件“一裂即斷”的彎曲破壞形態(tài)不同，SHCC表現(xiàn)出明顯的應變硬化和多微裂縫破壞特征；PVA纖維對SHCC的增強和增韌作用在100℃之前變化較小，200℃時大幅下降；PVA-SHCC在300℃時喪失韌性，表現(xiàn)出脆性破壞形態(tài)；內(nèi)摻硅烷乳液防水處理對不同溫度作用后SHCC的強度、變形能力、能量吸收能力、韌性等力學性能影響較小。毛細吸水試驗結果表明，不同溫度作用后SHCC的毛細吸水量和毛細吸收系數(shù)均高于基準試件，PVA纖維的引入降低了SHCC的抗?jié)B性能；內(nèi)摻硅烷乳液防水處理明顯降低了SHCC的毛細吸水量和毛細吸收系數(shù)，有效改善了SHCC的抗?jié)B性能；硅烷乳液防水劑發(fā)生分解的溫度區(qū)間為200℃-300℃，300℃時，硅烷乳液防水劑未完全失效，仍能表現(xiàn)出良好的防水效果。
[Abstract]:Fire, earthquake and even humidity are the main factors to accelerate the deterioration of reinforced concrete structure, which seriously affect the durability and safety of the whole structure. Therefore, the structure needs to be maintained, repaired and strengthened during its life cycle. The development of traditional cement-based materials is limited by their own brittleness, low tensile strength and easy cracking. However, with the development of modern civil engineering to large span, light, towering structures and underground, ocean, etc. The requirements of engineering structures for the properties of repair materials are becoming higher and higher. PVA-SHCC: PolyvinylAlcohol Fiber Reinforced Strain-Hardening Cementitious composer (PVA-SHCC: PolyvinylAlcohol Fiber Reinforced Strain-Hardening Cementitious composer) has the characteristics of high toughness, strain hardening, multi-microcrack failure, high energy dissipation and so on. It is of great significance to improve the durability and seismic resistance of structures by durability protection or repair and reinforcement of existing damaged parts. In this paper, the flexural strength test, compressive strength test, three-point bending test, four-point bending test and capillary water absorption test are used to study the effects of high temperature, waterproof treatment with admixture type on the flexural strength, compressive strength, flexural bearing capacity and deformation ability of PVA-SHCC. The effects of energy absorption, flexural toughness and impermeability were compared with the reference specimen without PVA fiber. The results of mechanical properties test show that the addition of PVA fiber can significantly improve the flexural strength, bending ability, deformation ability, energy absorption ability and bending toughness of SHCC. Increasing the compressive strength of SHCC to some extent the introduction of PVA fiber changes the bending failure pattern of SHCC. Different from the flexural failure pattern of the reference specimen, SHCC shows obvious strain hardening and multi-crack failure characteristics. The reinforcing and toughening effect of PVA fiber on SHCC decreases significantly when the change is less than 200 鈩，

本文編號：1818672