Charlotte Dewitte , Laurie Lacarrière , Mejdi Neji , Alexandra Bertron , Alexandre Dauzères
{"title":"含镁环境中低 PH 值水泥浆模型的化学机械特性分析","authors":"Charlotte Dewitte , Laurie Lacarrière , Mejdi Neji , Alexandra Bertron , Alexandre Dauzères","doi":"10.1016/j.cemconres.2024.107598","DOIUrl":null,"url":null,"abstract":"<div><p>In contact with natural waters, concrete can be exposed to the action of magnesium. Mg-attack on the cement paste leads to dissolution of cementitious phases and formation of brucite, hydrotalcite and/or magnesium silicate hydrates (M-S-H). The knowledge of the properties of the latter is limited. In binders with supplementary cementitious materials, M-S-H formation is favoured over that of brucite because of the lower contents of portlandite. To investigate the effects of a magnesium attack on such binders, a low Ca/Si model cement paste was immersed in a 5 mmol/L MgCl<sub>2</sub> solution for several months. Energy-dispersive spectrometry analyses coupled with X-ray diffraction and electron probe microanalyses showed Ca leaching, Si preservation and Mg enrichment of the altered zones of the pastes corresponding to the dissolution of C-S-H and formation of M-S-H and amorphous silica. The Mg-enriched zone showed a lower residual Young's modulus than the sound zone as measured by microindentation.</p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":null,"pages":null},"PeriodicalIF":10.9000,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0008884624001790/pdfft?md5=9750520585259d679ee006aad537fc9b&pid=1-s2.0-S0008884624001790-main.pdf","citationCount":"0","resultStr":"{\"title\":\"Chemo-mechanical characterization of a low-pH model cement paste in magnesium bearing environment\",\"authors\":\"Charlotte Dewitte , Laurie Lacarrière , Mejdi Neji , Alexandra Bertron , Alexandre Dauzères\",\"doi\":\"10.1016/j.cemconres.2024.107598\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><p>In contact with natural waters, concrete can be exposed to the action of magnesium. Mg-attack on the cement paste leads to dissolution of cementitious phases and formation of brucite, hydrotalcite and/or magnesium silicate hydrates (M-S-H). The knowledge of the properties of the latter is limited. In binders with supplementary cementitious materials, M-S-H formation is favoured over that of brucite because of the lower contents of portlandite. To investigate the effects of a magnesium attack on such binders, a low Ca/Si model cement paste was immersed in a 5 mmol/L MgCl<sub>2</sub> solution for several months. Energy-dispersive spectrometry analyses coupled with X-ray diffraction and electron probe microanalyses showed Ca leaching, Si preservation and Mg enrichment of the altered zones of the pastes corresponding to the dissolution of C-S-H and formation of M-S-H and amorphous silica. The Mg-enriched zone showed a lower residual Young's modulus than the sound zone as measured by microindentation.</p></div>\",\"PeriodicalId\":266,\"journal\":{\"name\":\"Cement and Concrete Research\",\"volume\":null,\"pages\":null},\"PeriodicalIF\":10.9000,\"publicationDate\":\"2024-07-05\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"https://www.sciencedirect.com/science/article/pii/S0008884624001790/pdfft?md5=9750520585259d679ee006aad537fc9b&pid=1-s2.0-S0008884624001790-main.pdf\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Cement and Concrete Research\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S0008884624001790\",\"RegionNum\":1,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"CONSTRUCTION & BUILDING TECHNOLOGY\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Cement and Concrete Research","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0008884624001790","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CONSTRUCTION & BUILDING TECHNOLOGY","Score":null,"Total":0}
Chemo-mechanical characterization of a low-pH model cement paste in magnesium bearing environment
In contact with natural waters, concrete can be exposed to the action of magnesium. Mg-attack on the cement paste leads to dissolution of cementitious phases and formation of brucite, hydrotalcite and/or magnesium silicate hydrates (M-S-H). The knowledge of the properties of the latter is limited. In binders with supplementary cementitious materials, M-S-H formation is favoured over that of brucite because of the lower contents of portlandite. To investigate the effects of a magnesium attack on such binders, a low Ca/Si model cement paste was immersed in a 5 mmol/L MgCl2 solution for several months. Energy-dispersive spectrometry analyses coupled with X-ray diffraction and electron probe microanalyses showed Ca leaching, Si preservation and Mg enrichment of the altered zones of the pastes corresponding to the dissolution of C-S-H and formation of M-S-H and amorphous silica. The Mg-enriched zone showed a lower residual Young's modulus than the sound zone as measured by microindentation.
期刊介绍:
Cement and Concrete Research is dedicated to publishing top-notch research on the materials science and engineering of cement, cement composites, mortars, concrete, and related materials incorporating cement or other mineral binders. The journal prioritizes reporting significant findings in research on the properties and performance of cementitious materials. It also covers novel experimental techniques, the latest analytical and modeling methods, examination and diagnosis of actual cement and concrete structures, and the exploration of potential improvements in materials.