【摘要】：西北干寒地區(qū)的混凝土常年受到凍融循環(huán)、鹽堿腐蝕、風蝕等多種自然因素的作用,日積月累,極易在混凝土結構中產生裂縫、剝蝕等病害�；炷亮芽p等病害如不及時修復,會加速混凝土結構的劣化,嚴重降低混凝土結構的耐久性,進而影響其安全服役。因此,研究如何修補產生裂縫等病害的混凝土,以及用什么材料修補具有重要的工程意義。本文針對西北干寒、鹽堿和風蝕等自然環(huán)境,研究了適合于該地區(qū)混凝土病害的修補用聚合物砂漿。本文研究了乳化瀝青、CR乳液和丙烯酸乳液改性聚合物砂漿的拌制、養(yǎng)護、工作性能、粘結性能和力學性能,分析了乳化瀝青、CR乳液和丙烯酸乳液加入量對聚合物改性砂漿含氣量、凝結時間、流動性、粘結性和力學性能的影響,對比分析不同改性乳液對各項指標的影響。從最后的研究成果來看,與普通砂漿相比,聚合物改性砂漿的抗折強度和抗壓強度均略有下降,隨著聚合物乳液摻量的增加強度先增大后減小,最佳摻量為15%左右;聚合物乳液和摻合料的摻入使砂漿在西北地區(qū)的條件下亦能獲得較好的內部孔結構和較高的力學強度,這表明改性砂漿比普通砂漿更適合于條件復雜的現(xiàn)場施工;聚合物乳液可以起到減水的效果。稠度固定時,水灰比例會逐漸減小,水泥水化過程和速度依舊沒有飛速加快,而是根據(jù)聚合物摻量比例的加大,初凝時間和終凝時間按照先降低后升高的曲線發(fā)展規(guī)律,但從凝結時間曲線來分析,聚合物并沒有加速凝結作用,在聚合物添加很多的情況下才具有較強的緩凝作用。氯丁膠乳的摻入大大提高了砂漿的抗壓強度,28d齡期時相對純砂漿增加2.7%。丙烯酸乳液的摻入對砂漿的抗折強度的提高顯著。28d齡期聚合物摻量為20%時,抗折強度影響最大,比純砂漿要高3.6%。90d時抗壓強度相對純砂漿提高了9%。聚合物改性砂漿的折壓比與齡期的關系呈反比。即齡期是增大聚合物改性砂減小,主要是由于砂漿的抗壓強度比抗折強度同期增加幅度要大。砂漿的粘結強度與摻量含量成正比,摻入量增加而粘結強度增長。對粘結強度的影響最為顯著的當屬氯丁膠乳,90d時粘結強度提高了20%。但丙烯酸在同一齡期時則降低了聚合物改性砂漿的粘結強度。主要原因是由于丙烯酸摻入量過多。它的量比在砂漿中沒有促進形成網(wǎng)狀的聚合物膜的效果,相反還減緩了水泥的水化過程。通過試驗數(shù)據(jù)可以推算出最佳養(yǎng)護環(huán)境并對養(yǎng)護條件的匹配性機理進行分析。
[Abstract]:The concrete in the dry and cold area of northwest China is affected by many natural factors such as freeze-thaw cycle, salt alkali corrosion, wind erosion and so on. It is easy to produce cracks and denudation in concrete structure. If concrete cracks and other diseases are not repaired in time, the deterioration of concrete structures will be accelerated, the durability of concrete structures will be seriously reduced, and the safety of concrete structures will be affected. Therefore, it is of great engineering significance to study how to repair concrete with cracks and other diseases and what materials to repair. In this paper, polymer mortar suitable for repairing concrete diseases in Northwest China is studied, which is suitable for repairing concrete diseases in northwest China, such as dry cold, salt alkali and wind erosion. In this paper, the mixing, curing, working properties, bond properties and mechanical properties of emulsified asphalt, CR emulsion and acrylic emulsion modified polymer mortar are studied. The effects of the amount of CR emulsion and acrylic emulsion on the air content, setting time, fluidity, adhesion and mechanical properties of polymer modified mortar were compared and analyzed. Compared with ordinary mortar, the flexural strength and compressive strength of polymer modified mortar decreased slightly. With the increase of polymer emulsion content, the flexural strength and compressive strength of polymer modified mortar increased first and then decreased, and the optimum content was about 15%. The addition of polymer emulsion and admixture makes the mortar obtain better internal pore structure and higher mechanical strength under the condition of northwest China, which indicates that the modified mortar is more suitable for the field construction with complex conditions than ordinary mortar. Polymer emulsion can reduce water. When the consistency is fixed, the water-cement ratio will gradually decrease, and the hydration process and speed of cement will not accelerate rapidly, but according to the increase of polymer content ratio, the initial setting time and the final setting time develop according to the curve of decreasing first and then increasing. However, according to the setting time curve, the polymer does not accelerate the condensation, and it has a strong retarding effect only when the polymer is added a lot. The compressive strength of mortar was greatly increased with the addition of Chloroprene latex, and the relative pure mortar increased by 2.7% at 28d age. The flexural strength of mortar increased significantly with the addition of acrylic acid emulsion. When the polymer content of 28 days was 20, the flexural strength of mortar was the greatest, and the compressive strength was increased by 9% compared with pure mortar at 3.60.90 d than that of pure mortar. The relationship between the flexural pressure ratio and the age of polymer modified mortar is inversely proportional. The main reason is that the compressive strength of mortar is larger than that of flexural strength. The bond strength of mortar is in direct proportion to the content of mortar. The most significant effect on the bond strength was Chloroprene latex, which increased the bond strength by 20 times after 90 days. However, acrylic acid decreased the bond strength of polymer modified mortar at the same age. The main reason is the excessive incorporation of acrylic acid. The ratio does not promote the formation of the polymer membrane in mortar, on the contrary, it slows down the hydration process of cement. The optimum curing environment can be deduced from the test data and the matching mechanism of the curing conditions can be analyzed.
【學位授予單位】：蘭州交通大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU578.1

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