本文選題：聚合物改性水泥砂漿 + 配合比�。� 參考：《北京建筑大學(xué)》2017年碩士論文

【摘要】：在實際應(yīng)用中,許多混凝土結(jié)構(gòu)設(shè)計除了承受正常的設(shè)計荷載外,有可能承受如沖擊、爆炸、地震等不確定外力的作用。選擇好的加固方式對現(xiàn)有的鋼筋混凝土結(jié)構(gòu)進行加固、維護變的尤為重要。高強鋼絲繩網(wǎng)—聚合物改性水泥砂漿加固是現(xiàn)如今新發(fā)展的新型加固方式,較好的耐火性和耐久性,逐漸成為國內(nèi)外學(xué)者廣泛關(guān)注的混凝土結(jié)構(gòu)加固工藝。該加固工藝中,高性能砂漿的性能對加固效果起到至關(guān)重要的作用,現(xiàn)如今對聚合物改性水泥砂漿(以下簡稱砂漿)的動態(tài)力學(xué)性能研究較少。為了拓展該加固技術(shù)在抗爆抗沖擊領(lǐng)域內(nèi)的應(yīng)用范圍,很有必要系統(tǒng)研制適用于沖擊環(huán)境下的高性能砂漿。本文對高性能砂漿的研制和動態(tài)性能進行了系統(tǒng)研究,主要做了兩方面的工作:一是配制砂漿配合比及研究材料摻量對砂漿力學(xué)性能的影響;二是研究確定砂漿應(yīng)變率效應(yīng)及非線性損傷本構(gòu)關(guān)系。具體研究成果和結(jié)論如下:1.試配用于高強鋼絲繩網(wǎng)片-聚合物改性水泥砂漿加固技術(shù)中的高性能砂漿,本文試驗條件下研究了水膠比、膠粉摻量、粉末減水劑摻量、纖維摻量等對砂漿抗壓強度、抗折強度、粘結(jié)性能和流動度等力學(xué)性能和耐久性的影響,結(jié)果如下:(1)通過試配確定力學(xué)性能和施工性能均能滿足混凝土結(jié)構(gòu)加固設(shè)計規(guī)范的要求的配比,即水膠比為0.24,膠砂比為2,膠粉摻量為2%,纖維摻量為0.15%。(2)聚合物摻量為2%時,砂漿的抗壓強度、抗折強度和粘結(jié)強度等性能得到大幅度改善;隨水膠比的增大,砂漿的抗壓、抗折強度和界面粘結(jié)強度減小,流動度增大;當(dāng)纖維摻量為0.15%時,砂漿的耐久性、抗裂性和韌性作用顯著提高;粉末減水劑摻量在0.4%-0.6%范圍內(nèi),對砂漿的抗壓、抗折強度等力學(xué)性能無顯著變化,主要會對砂漿的抹面施工性能和流動度的影響。2.通過霍普金森壓桿(SHPB)沖擊壓縮試驗,研究了砂漿的沖擊破壞形態(tài)及應(yīng)變率效應(yīng)。研究結(jié)果表明:(1)聚合物改性水泥砂漿是一種應(yīng)變率敏感材料。砂漿的動態(tài)強度隨應(yīng)變率的增大而提高,其應(yīng)變率效應(yīng)隨砂漿強度的增大而降低。彈性模量隨應(yīng)變率的增大逐步降低。(2)隨著加載速率的增大、砂漿試塊的破壞形態(tài)變化顯著,大致分為:無裂紋,少量裂紋、大量裂紋整體完整、大量裂紋且整體性差、粉碎破壞等。(3)當(dāng)沖擊速度及纖維摻量一定時,砂漿強度越大,試塊的破壞程度越小,即裂紋越少及破碎程度越低;(4)砂漿強度分別為60MPa和50MPa時,隨著纖維摻量的增加,砂漿的峰值應(yīng)力、峰值韌性和極限韌性先增大后減小,其作用效果高于70MPa砂漿;鋼纖維砂漿相比PVA砂漿和PF砂漿,摻入足量的纖維可以提高砂漿的韌性和抗沖擊性能,且增強效果更加明顯。(5)根據(jù)試驗數(shù)據(jù)參數(shù)擬合的ZWT本構(gòu)模型與試驗所得應(yīng)力-應(yīng)變曲線吻合度較好,該模型可以用來描述砂漿在沖擊荷載作用下不同應(yīng)變率的本構(gòu)關(guān)系。
[Abstract]:In practical application, many concrete structures may bear the effects of uncertain external forces, such as shock, explosion, earthquake and so on, in addition to the normal design load. It is very important to choose a good reinforcement method to reinforce the existing reinforced concrete structure. The reinforcement of high-strength steel wire rope network-polymer modified cement mortar is a new type of reinforcement method. The better fire resistance and durability gradually become the strengthening technology of concrete structure which is widely concerned by domestic and foreign scholars. In this reinforcement process, the performance of high performance mortar plays an important role in the reinforcement effect. Nowadays, the dynamic mechanical properties of polymer modified cement mortar (hereinafter referred to as mortar) are less studied. In order to expand the application scope of the reinforcement technology in the field of anti-explosion and anti-impact, it is necessary to systematically develop the high performance mortar suitable for impact environment. In this paper, the development and dynamic performance of high performance mortar have been studied systematically. Two aspects of work have been done: first, the mix ratio of mortar and the effect of material content on the mechanical properties of mortar; The second is to determine the strain rate effect and nonlinear damage constitutive relation of mortar. The specific research results and conclusions are as follows: 1. In this paper, the compressive strength of high strength steel wire rope mesh-polymer modified cement mortar was studied under the experimental conditions, such as water / binder ratio, rubber powder content, powder water reducing agent content, fiber content, etc. The effects of mechanical properties and durability, such as flexural strength, bond strength and fluidity, are as follows: (1) the ratio of mechanical properties and construction properties can meet the requirements of the design code for strengthening concrete structures. When the ratio of water to binder is 0.24, the ratio of cement to sand is 2, the amount of rubber powder is 2, and the content of fiber is 0.15.1%, the properties of mortar such as compressive strength, flexural strength and bond strength are greatly improved, and the compressive strength of mortar increases with the increase of water-binder ratio. When the fiber content is 0.15, the durability, crack resistance and toughness of mortar are improved significantly, and the compressive strength of mortar is increased in the range of 0.4% -0.6% of powder water reducing agent. The mechanical properties, such as flexural strength, have no significant change, but mainly affect the construction performance and fluidity of mortar. The impact failure mode and strain rate effect of mortar were studied by means of the impact compression test of Hopkinson compression bar (SHPB). The results show that polymer modified cement mortar is a strain rate sensitive material. The dynamic strength of mortar increases with the increase of strain rate, and the strain rate effect decreases with the increase of mortar strength. The modulus of elasticity decreases gradually with the increase of strain rate. (2) with the increase of loading rate, the failure mode of mortar specimen changes significantly, which can be roughly divided into three parts: no crack, a small amount of crack, a large number of cracks, and the integrity is poor. When the impact speed and fiber content are constant, the higher the mortar strength is, the smaller the damage degree of the test block is, that is, the less cracks and the lower the crushing degree are, the higher the mortar strength is 60 MPA and 50 MPA, respectively, with the increase of fiber content. The peak stress, peak toughness and ultimate toughness of mortar first increase and then decrease, and its effect is higher than that of 70 MPA mortar. Compared with PVA mortar and PF mortar, the fiber of steel fiber mortar can improve the toughness and impact resistance of mortar. And the enhancement effect is more obvious. (5) the ZWT constitutive model fitted according to the parameters of the test data is in good agreement with the stress-strain curve obtained from the test. The model can be used to describe the constitutive relations of mortar under different strain rates under impact load.
【學(xué)位授予單位】：北京建筑大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TQ177.62

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