Alexander S. Brand , Steven B. Feldman , Paul E. Stutzman , Anton V. Ievlev , Matthias Lorenz , Darren C. Pagan , Sriramya Nair , Justin M. Gorham , Jeffrey W. Bullard
{"title":"Dissolution and initial hydration behavior of tricalcium aluminate in low activity sulfate solutions","authors":"Alexander S. Brand , Steven B. Feldman , Paul E. Stutzman , Anton V. Ievlev , Matthias Lorenz , Darren C. Pagan , Sriramya Nair , Justin M. Gorham , Jeffrey W. Bullard","doi":"10.1016/j.cemconres.2020.105989","DOIUrl":null,"url":null,"abstract":"<div><p>Influences of alkali or alkaline earth sulfates on the hydration of cubic tricalcium aluminate (C<sub>3</sub>A) were evaluated by <em>in situ</em> dissolution rate measurements, by <em>ex situ</em> near-surface composition measurements with secondary ion mass spectrometry, and by <em>in situ</em> synchrotron X-ray diffraction to monitor precipitation of hydration products. Both slight reductions in dissolution rate and cation-specific interactions with the solid were observed. The near-surface Ca/Al ratio is significantly lower after some dissolution and the electrolyte cations are incorporated within the surface with different affinities (Mg<sup>2+</sup> > K<sup>+</sup> > Na<sup>+</sup>). An interfacial dissolution-reprecipitation mechanism may explain the observations as well as, or better than, a simple cation exchange. The sulfate concentration in solution affects the rates of both C<sub>3</sub>A dissolution and precipitation of hydration products. Sulfate ions likely adsorb at the hydrous Al-rich surface layer, thereby reducing the dissolution rate of aluminates and delaying the precipitation of aluminate hydration products.</p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"130 ","pages":"Article 105989"},"PeriodicalIF":10.9000,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/j.cemconres.2020.105989","citationCount":"29","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Cement and Concrete Research","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0008884619313286","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: 29
Abstract
Influences of alkali or alkaline earth sulfates on the hydration of cubic tricalcium aluminate (C3A) were evaluated by in situ dissolution rate measurements, by ex situ near-surface composition measurements with secondary ion mass spectrometry, and by in situ synchrotron X-ray diffraction to monitor precipitation of hydration products. Both slight reductions in dissolution rate and cation-specific interactions with the solid were observed. The near-surface Ca/Al ratio is significantly lower after some dissolution and the electrolyte cations are incorporated within the surface with different affinities (Mg2+ > K+ > Na+). An interfacial dissolution-reprecipitation mechanism may explain the observations as well as, or better than, a simple cation exchange. The sulfate concentration in solution affects the rates of both C3A dissolution and precipitation of hydration products. Sulfate ions likely adsorb at the hydrous Al-rich surface layer, thereby reducing the dissolution rate of aluminates and delaying the precipitation of aluminate hydration products.
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.