接触溶蚀条件下混凝土游离钙离子固化效果研究

为研究将硅灰和硅酸钠作为掺合料内掺后的喷射混凝土在接触溶蚀条件下析出钙离子的规律,在不同掺量下制备了单掺和复掺混凝土试块,开展30 d去离子水浸泡试验,测试溶液中的钙离子浓度、溶液pH值的变化情况,并结合SEM等微观检测对接触溶蚀过程进行研究。结果显示：单掺硅灰试块在不换水条件下的钙离子溶出量大大低于空白组,换水条件下30 d内3%、5%、7%掺量组较空白组平均溶出钙离子总重依次减少73.29%、69.65%、69.26%;单掺硅酸钠后,不换水条件下3%掺量的试块钙离子溶出量也能得到明显的降低,换水条件下30 d内1%、3%、5%掺量组较空白组平均溶出钙离子总重依次减少9.22%、20.53%、29.96%;将单掺组中固化效果良好的3%掺量硅灰和5%掺量硅酸钠复掺入混凝土后,不换水条件下浸泡溶液初始钙离子浓度仅为20～30 mg/L,从第18天左右溶液游离钙离子清零,换水条件下复掺试块较空白组平均溶出钙离子总重减少约85%。     

隋使遍光高与东亚佛教外交

一、隋使使日 文化的交流是双向的,礼尚往来,互通有无.自古中日两国的通交也是你来我往,十分频繁.史载第一个赴日的外交使团为<魏志·倭人传>所载曹魏派遣的张政一行.该次遣使是在邪马台国多次遣使之后所派出的,当时曹魏与邪马台国的交往频繁,十分友好,可以说是中日两国通交的第一个高潮.至隋时,随着两国交往的深入和"国书问题"的发生,中央政府派出的裴世清一行12人的访日使团是中国古代第二个代表中央政府正式访问日本的外交使团.[1]     

接触溶蚀条件下玻璃粉对混凝土抗钙溶蚀能力的影响

The precipitation of calcium ions from concrete is one of the main causes that will lead to crystallization in tunnel drainage systems. To study the effect of glass dust on the resistance of concrete to calcium corrosion under contact corrosion conditions, this study prepares some concrete test specimens and cement mortar test specimens by replacing 0%, 10%, 15% and 20% of the cement with equal mass of glass dust to carry out deionized water immer⁃ sion tests to detect the calcium ion concentration. X-ray diffractometer and scanning electron microscope are used to analyze and study the type, content, microscopic morphology and element composition of the hydrated products of the test specimens. The results show that glass dust can reduce the content of calcium hydroxide (CH) and the pre⁃ cipitation of calcium ions in the hydrated products of the cement mortars, and the best effect is achieved when 10% of glass dust is mixed. When the corrosion lasts 28 d, the microstructure of the cement mortars mixed with glass dust is improved compared with that of cement mortars without any glass dust, but the volcanic ash activity of the glass dust has not yet been fully brought into play. © 2023 Editorial By Modern Tunnelling Technology. All rights reserved.