【摘要】：近年來,碳纖維增強(qiáng)高分子(CFRP)復(fù)合材料被廣泛應(yīng)用于土木工程結(jié)構(gòu)的加固、修復(fù)或新建結(jié)構(gòu),由于在土木工程中環(huán)境復(fù)雜、結(jié)構(gòu)服役壽命長,CFRP復(fù)合材料的耐久性能問題逐漸凸顯,特別是在潮濕或堿性環(huán)境(如混凝土內(nèi)部環(huán)境)下,CFRP復(fù)合材料的長期性能演化關(guān)系到FRP增強(qiáng)結(jié)長期服役的安全性。乙烯基酯樹脂具有優(yōu)異的耐水、耐化學(xué)腐蝕等特性,且由于粘度低,加工性能優(yōu)于環(huán)氧樹脂。因此,本文采用升溫加速試驗(yàn)方法,研究乙烯基酯樹脂與碳纖維增強(qiáng)乙烯基酯拉擠板材在水或強(qiáng)堿溶液浸泡條件下的性能演化及退化機(jī)理,該研究將促進(jìn)高耐久性能CFRP復(fù)合材料的開發(fā)及其土木工程結(jié)構(gòu)的應(yīng)用。乙烯基酯樹脂在固化過程中產(chǎn)生較大收縮;浸泡于水或強(qiáng)堿溶液其吸水符合兩階段水吸收行為;吸水導(dǎo)致樹脂發(fā)生溶脹,在水浸泡下其溶脹應(yīng)變遠(yuǎn)小于收縮應(yīng)變,而堿液浸泡下溶脹應(yīng)變大于收縮應(yīng)變;樹脂吸水后塑化明顯,樹脂酯鍵在水或強(qiáng)堿浸泡條件下發(fā)生水解,且強(qiáng)堿浸泡會加速樹脂的水解反應(yīng);水、堿液浸泡使乙烯基酯樹脂的力學(xué)性能發(fā)生退化,且堿液浸泡下樹脂力學(xué)性能的破壞較水浸泡下的更為嚴(yán)重。乙烯基酯CFRP拉擠板材在水、堿液浸泡過程中的吸水也符合兩階段水吸收行為;樹脂基體和碳纖維-樹脂粘結(jié)界面吸收水分,且界面的吸水乙烯基酯CFRP起主要作用。短梁剪切強(qiáng)度和面內(nèi)剪切強(qiáng)度結(jié)果表明,水或強(qiáng)堿溶液浸泡導(dǎo)致碳纖維-樹脂的界面粘結(jié)性能發(fā)生不可逆退化,且堿加速界面粘結(jié)性能的退化。動態(tài)熱力學(xué)性能測試結(jié)果和掃描電鏡結(jié)果驗(yàn)證了界面粘結(jié)性能的退化。水、堿液浸泡使乙烯基酯CFRP拉擠板材的力學(xué)性能發(fā)生退化,且堿液浸泡加速樹脂力學(xué)性能的退化,在浸泡后期抗拉強(qiáng)度和抗拉模量都趨于穩(wěn)定值;在試驗(yàn)初期乙烯基酯CFRP拉擠板材抗拉強(qiáng)度由基體模量變化和界面變化共同決定,之后隨著基體吸水達(dá)到穩(wěn)定乙烯基酯CFRP拉擠板材內(nèi)外模量差值不斷減小,界面剪力同時(shí)隨之減小,乙烯基酯CFRP拉擠板材抗拉強(qiáng)度將由受拉時(shí)纖維應(yīng)力的均勻程度決定。VE具有優(yōu)異的耐水、耐堿性能,但乙烯基酯CFRP拉擠板材的界面性能在水或堿浸泡下卻快速退化,而其拉伸性能影響較小,為提高乙烯基酯CFRP板材的耐水或強(qiáng)堿溶液浸泡性能,需要著重研究如何提高碳纖維與乙烯基酯界面粘結(jié)性能,如開發(fā)適合乙烯基酯的碳纖維表面上漿處理劑。
[Abstract]:In recent years, carbon fiber reinforced polymer (CFRP) composites have been widely used in the reinforcement, repair or construction of civil engineering structures, due to the complex environment in civil engineering. The durability of CFRP composites with long service life is becoming more and more serious, especially in wet or alkaline environment (such as in concrete). The evolution of long-term performance of CFRP composites is related to the long-term service safety of FRP reinforced junctions. Vinyl ester resin is superior to epoxy resin because of its low viscosity and excellent resistance to water and chemical corrosion. Therefore, the properties evolution and degradation mechanism of vinyl ester resin and carbon fiber reinforced vinyl ester extruded sheet in water or strong alkali solution were studied by means of accelerated heating test. This study will promote the development of high durability CFRP composites and the application of civil engineering structures. The water absorption of vinyl ester resin in water or strong alkali solution accords with the two-stage water absorption behavior. The swelling strain of vinyl ester resin is much smaller than that of shrinkage strain when it is soaked in water. The swelling strain is larger than the shrinkage strain, the resin is plasticized obviously after absorbing water, the resin ester bond is hydrolyzed under the condition of water or strong alkali soaking, and the strong alkali soaking accelerates the hydrolysis reaction of the resin. The mechanical properties of vinyl ester resin were degraded by alkali soaking, and the destruction of mechanical properties of vinyl ester resin was more serious than that of water immersion. The water absorption of vinyl ester CFRP extruded sheet in water and alkali solution soaking also accords with the two-stage water absorption behavior; the resin matrix and carbon fiber resin bond interface absorbs water and the interface water absorption vinyl ester CFRP plays a major role. The results of shear strength and in-plane shear strength of short beam show that soaking in water or strong alkali solution leads to irreversible degradation of interfacial bond property of carbon fiber resin and alkali accelerates the degradation of interfacial bond property. The degradation of interfacial adhesion was verified by the dynamic thermodynamic properties and SEM results. The mechanical properties of vinyl ester CFRP extruded sheet were degraded by water and alkali soaking, and the mechanical properties of the resin were accelerated by alkali soaking. The tensile strength and tensile modulus of the resin tended to be stable at the later stage of soaking. At the beginning of the experiment, the tensile strength of vinyl ester CFRP pullout plate was determined by the change of matrix modulus and interface, and then the difference between internal and external modulus of vinyl ester CFRP sheet was decreased with the water absorption of the matrix reaching stable. The interfacial shear force decreases at the same time. The tensile strength of vinyl ester CFRP extruded sheet is determined by the uniformity of fiber stress when it is pulled. VE has excellent water resistance and alkali resistance. However, the interfacial properties of vinyl ester CFRP extruded sheets rapidly degenerate under water or alkali soaking, while the tensile properties of vinyl ester CFRP sheets have little effect. In order to improve the soaking performance of vinyl ester CFRP sheets in water or strong alkali solution, It is necessary to study how to improve the interfacial bond between carbon fiber and vinyl ester, such as the development of carbon fiber surface sizing agent suitable for vinyl ester.
【學(xué)位授予單位】：哈爾濱工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TB332

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本文編號：2131834