磷化及硫酸盐侵蚀对水泥砂浆损伤影响研究
发布时间：2018-12-21 18:26
【摘要】：钢筋混凝土结构应用于土木工程中已有100多年的历史,实际工程中的钢筋混凝土结构大都受机械荷载与环境荷载的复合作用。在我国沿海或西部盐湖地区,混凝土通常会遭受硫酸盐侵蚀和碳化,因此研究其单一作用以及复合作用具有重要意义。本课题研究了两种水泥(普通硅酸盐水泥、高抗硫酸盐水泥),3个水灰比(W/C=0.4,0.5,0.6)的砂浆试块在单独碳化作用下的相对动弹性模量、抗折抗压强度及碳化后试块各深度处的CaC03含量的变化,单独硫酸盐侵蚀作用下的试块长度变化、相对动弹性模量变化、抗折抗压强度变化以及硫酸根离子含量的变化,硫酸盐侵蚀和碳化复合作用下的抗折抗压强度、相对动弹性模量、CaCO3含量的变化。得到的主要结论有：(1)水泥砂浆试块只进行碳化试验时,在一定的碳化龄期内,水泥砂浆试块的相对动弹性模量随着碳化时间的增加而增加,但其增长速率随碳化时间的延长而呈减缓趋势。(2)水泥砂浆试块只进行碳化试验时,水泥砂浆试块的抗折强度随碳化时间的增加而增加,当砂浆试块水灰比较小(W/C=0.4)时,抗折强度随着碳化时间的增加而增加,当水灰比较大(W/C=0.5、0.6)时水泥砂浆试块的抗折强度随碳化时间的增加先增大后减小。碳化28d后,其抗压强度比未碳化时提高了40%～50%；最大的抗折强度比未碳化时提高了20%～30%。(3)普通硅酸盐水泥砂浆试块泡水180d后,长度增长0.02%～0.04%,浸泡5%Na2SO4溶液180d,长度增长0.04%～0.09%；高抗硫酸盐水泥砂浆试块泡水180d后,长度增长0.02%～0.04%,浸泡5%Na2SO4溶液180d,长度增长0.03%～0.05%。(4)水泥(普通硅酸盐水泥、高抗硫酸盐水泥)砂浆试块的抗折抗压强度都随着泡水时间的增长而增加,砂浆试块浸泡在水中180d后,其抗折强度比未浸泡时增加了20%～30%,抗压强度比未浸泡时增加了50%～60‰而浸泡在硫酸盐溶液中的水泥砂浆试块的抗折抗压强度都随着浸泡时间的增长,呈先增大后减小的趋势：普通硅酸盐水泥砂浆试块最大的抗折强度比未浸泡时增长20%～30%,最大抗压强度比未浸泡时增长40%～50%,浸泡180d后的抗折强度比最大的抗折强度减小10%～30%,抗压强度比最大的抗压强度减小10%～40%。高抗硫酸盐水泥砂浆试块最大的抗折强度与未浸泡时相比增长20%～30%,最大抗压强度与未浸泡时相比增长50%～60%,浸泡180d后的抗折强度比最大的抗折强度减小了20%～30%,抗压强度比最大的抗压强度减小了10%～20%。(5)砂浆试块浸泡在5%Na2SO4溶液中180d内,自由硫酸根离子含量随着渗透深度的加深呈递减的趋势,在离砂浆表面6～10mm后,自由硫酸根离子含量趋于稳定。(6)在一定的侵蚀龄期、碳化龄期内,各水灰比的水泥砂浆试块,硫酸盐侵蚀及碳化作用使其抗折抗压强度先增大后减小。(7)较长时间的硫酸盐侵蚀能加快碳化反应的进行。
[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，
本文编号：2389288
[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，
本文编号：2389288
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