【摘要】：鋼筋混凝土結(jié)構(gòu)應用于土木工程中已有100多年的歷史,實際工程中的鋼筋混凝土結(jié)構(gòu)大都受機械荷載與環(huán)境荷載的復合作用。在我國沿�；蛭鞑葵}湖地區(qū),混凝土通常會遭受硫酸鹽侵蝕和碳化,因此研究其單一作用以及復合作用具有重要意義。本課題研究了兩種水泥(普通硅酸鹽水泥、高抗硫酸鹽水泥),3個水灰比(W/C=0.4,0.5,0.6)的砂漿試塊在單獨碳化作用下的相對動彈性模量、抗折抗壓強度及碳化后試塊各深度處的CaC03含量的變化,單獨硫酸鹽侵蝕作用下的試塊長度變化、相對動彈性模量變化、抗折抗壓強度變化以及硫酸根離子含量的變化,硫酸鹽侵蝕和碳化復合作用下的抗折抗壓強度、相對動彈性模量、CaCO3含量的變化。得到的主要結(jié)論有：(1)水泥砂漿試塊只進行碳化試驗時,在一定的碳化齡期內(nèi),水泥砂漿試塊的相對動彈性模量隨著碳化時間的增加而增加,但其增長速率隨碳化時間的延長而呈減緩趨勢。(2)水泥砂漿試塊只進行碳化試驗時,水泥砂漿試塊的抗折強度隨碳化時間的增加而增加,當砂漿試塊水灰比較小(W/C=0.4)時,抗折強度隨著碳化時間的增加而增加,當水灰比較大(W/C=0.5、0.6)時水泥砂漿試塊的抗折強度隨碳化時間的增加先增大后減小。碳化28d后,其抗壓強度比未碳化時提高了40%～50%；最大的抗折強度比未碳化時提高了20%～30%。(3)普通硅酸鹽水泥砂漿試塊泡水180d后,長度增長0.02%～0.04%,浸泡5%Na2SO4溶液180d,長度增長0.04%～0.09%；高抗硫酸鹽水泥砂漿試塊泡水180d后,長度增長0.02%～0.04%,浸泡5%Na2SO4溶液180d,長度增長0.03%～0.05%。(4)水泥(普通硅酸鹽水泥、高抗硫酸鹽水泥)砂漿試塊的抗折抗壓強度都隨著泡水時間的增長而增加,砂漿試塊浸泡在水中180d后,其抗折強度比未浸泡時增加了20%～30%,抗壓強度比未浸泡時增加了50%～60‰而浸泡在硫酸鹽溶液中的水泥砂漿試塊的抗折抗壓強度都隨著浸泡時間的增長,呈先增大后減小的趨勢：普通硅酸鹽水泥砂漿試塊最大的抗折強度比未浸泡時增長20%～30%,最大抗壓強度比未浸泡時增長40%～50%,浸泡180d后的抗折強度比最大的抗折強度減小10%～30%,抗壓強度比最大的抗壓強度減小10%～40%。高抗硫酸鹽水泥砂漿試塊最大的抗折強度與未浸泡時相比增長20%～30%,最大抗壓強度與未浸泡時相比增長50%～60%,浸泡180d后的抗折強度比最大的抗折強度減小了20%～30%,抗壓強度比最大的抗壓強度減小了10%～20%。(5)砂漿試塊浸泡在5%Na2SO4溶液中180d內(nèi),自由硫酸根離子含量隨著滲透深度的加深呈遞減的趨勢,在離砂漿表面6～10mm后,自由硫酸根離子含量趨于穩(wěn)定。(6)在一定的侵蝕齡期、碳化齡期內(nèi),各水灰比的水泥砂漿試塊,硫酸鹽侵蝕及碳化作用使其抗折抗壓強度先增大后減小。(7)較長時間的硫酸鹽侵蝕能加快碳化反應的進行。
[Abstract]:Reinforced concrete structures have been used in civil engineering for more than 100 years. In the coastal or western salt lake areas of China, concrete is usually subject to sulfate erosion and carbonation, so it is of great significance to study its single action and composite action. In this paper, the relative dynamic elastic modulus of two kinds of cement (ordinary Portland cement, high sulphate resistant cement) and three mortar blocks with water / cement ratio (W / C = 0.4 / 0.50.6) were studied under the action of single carbonization. The changes of flexural strength and CaC03 content at different depths after carbonization, the changes of specimen length, relative dynamic elastic modulus, flexural strength and sulfate ion content, The changes of flexural compressive strength, relative dynamic elastic modulus and CaCO3 content under the action of sulfate erosion and carbonation. The main conclusions are as follows: (1) the relative dynamic elastic modulus of cement mortar specimen increases with the increase of carbonation time when the cement mortar test block is carbonized only, and the relative dynamic elastic modulus of cement mortar specimen increases with the increase of carbonation time in a certain carbonation period. However, the growth rate of cement mortar decreased with the increase of carbonization time. (2) when the cement mortar test block was carbonized only, the flexural strength of cement mortar specimen increased with the increase of carbonization time. The flexural strength increases with the increase of carbonization time when the water cement ratio (W/C=0.4) of mortar test blocks is small. The flexural strength of cement mortar increases firstly and then decreases with the increase of carbonization time when the water cement ratio is larger (W / C = 0.50.60). After 28 days of carbonization, the compressive strength increased by 40% and 50% than that without carbonization. The maximum flexural strength was 20% higher than that without carbonization. (3) after the ordinary Portland cement mortar was soaked in water for 180 days, the length increased by 0.02% and 0.04%, and the 5%Na2SO4 solution was soaked for 180 days and the length increased by 0.04% and 0.09%; After 180 days of bubbling water, the length of high resistant cement mortar increased by 0.02 and 0.04. The 5%Na2SO4 solution was soaked for 180 days and the length increased by 0.033 and 0.05. (4) cement (ordinary Portland cement), The flexural strength of mortar specimens increased with the increase of water bubble time. After immersion in water for 180 days, the flexural strength of mortar blocks increased by 20% and 30% than that without soaking. The compressive strength of cement mortar samples immersed in sulfate solution increased by 50% and 60 鈥，

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