{"title":"The deformation of CSH gels and its link with dynamic length change of cement pastes upon drying and resaturation","authors":"Chunsheng Zhou , Xiaoyu Zhang , Jing Qiao , Jingjing Feng , Qiang Zeng","doi":"10.1016/j.cemconres.2024.107693","DOIUrl":null,"url":null,"abstract":"<div><div>Drying shrinkage of cement pastes (CPs) facilitating superficial cracking deserves primary concern when evaluating durability performance. To clarify shrinkage mechanism, the changes of mass, length and pore-scale water allocation of two mature CPs were monitored non-destructively through low-field NMR relaxometry. Experimental results indicated that, heat treatment under hot water slightly coarsens the pore structure of CPs through modifying <figure><img></figure> packing, and reduces shrinkage remarkably through stiffening <figure><img></figure> clusters. Upon drying at 43% RH, the interlayer pores are still saturated and compacted with reduced volume. At 80% RH, although the interlayer and gel pores are both saturated, they lose water gradually at reducing rates. Drying shrinkages of CPs are caused by compaction of interlayer and gel pores, whose contributions to shrinkage are at the ratio of 1:3 roughly. Most of <figure><img></figure> compaction is compensated by the coarsening of pore structure, and only 2–6 percent shows up as observable shrinkage.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"187 ","pages":"Article 107693"},"PeriodicalIF":10.9000,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Cement and Concrete Research","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0008884624002746","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}
引用次数: 0
Abstract
Drying shrinkage of cement pastes (CPs) facilitating superficial cracking deserves primary concern when evaluating durability performance. To clarify shrinkage mechanism, the changes of mass, length and pore-scale water allocation of two mature CPs were monitored non-destructively through low-field NMR relaxometry. Experimental results indicated that, heat treatment under hot water slightly coarsens the pore structure of CPs through modifying packing, and reduces shrinkage remarkably through stiffening clusters. Upon drying at 43% RH, the interlayer pores are still saturated and compacted with reduced volume. At 80% RH, although the interlayer and gel pores are both saturated, they lose water gradually at reducing rates. Drying shrinkages of CPs are caused by compaction of interlayer and gel pores, whose contributions to shrinkage are at the ratio of 1:3 roughly. Most of compaction is compensated by the coarsening of pore structure, and only 2–6 percent shows up as observable shrinkage.
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.
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