{"title":"Strengthening of hollow glass microspheres via a new K2CO3-KOH-activated ion-exchange strategy","authors":"","doi":"10.1016/j.conbuildmat.2024.138629","DOIUrl":null,"url":null,"abstract":"<div><div>Hollow glass microspheres (HGMs) are lightweight fillers with potential applications in construction materials, but their limited compressive strength hinders widespread use. This study proposes a new strengthening strategy for HGMs by ion exchange treatment of K<sup>+</sup> with Na<sup>+</sup>. HGMs were treated in different molten salts at 520–600 °C for 1–6 h, and their compressive strength, density, moisture content, buoyancy, and microstructure were systematically studied. The compressive strength of HGMs in a mixed melt of KNO<sub>3</sub>-0.5 wt% KOH-3 wt% K<sub>2</sub>CO<sub>3</sub> reached a high value of 112 MPa after heating at 580 °C for only 3 h, compared to 80 MPa in pure KNO<sub>3</sub> after 24 h. Extended treatment caused some HGMs to fracture, reducing floatation and increasing density. Elemental analysis, including surface phase composition and cross-sectional distribution, confirmed the successful ion exchange of Na⁺ and K⁺. Increased densification of the HGMs formed a compressive stress layer on their thin walls, inhibiting crack extension and enhancing compressive strength. Overall, adjusting ion exchange parameters improved the compressive strength of HGMs, making them suitable for high-performance applications in aerospace, automotive, and marine engineering. Future efforts will aim to reduce costs or incorporate acid etching to improve surface stability and minimize material loss during strengthening.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":null,"pages":null},"PeriodicalIF":7.4000,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Construction and Building Materials","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0950061824037711","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
Hollow glass microspheres (HGMs) are lightweight fillers with potential applications in construction materials, but their limited compressive strength hinders widespread use. This study proposes a new strengthening strategy for HGMs by ion exchange treatment of K+ with Na+. HGMs were treated in different molten salts at 520–600 °C for 1–6 h, and their compressive strength, density, moisture content, buoyancy, and microstructure were systematically studied. The compressive strength of HGMs in a mixed melt of KNO3-0.5 wt% KOH-3 wt% K2CO3 reached a high value of 112 MPa after heating at 580 °C for only 3 h, compared to 80 MPa in pure KNO3 after 24 h. Extended treatment caused some HGMs to fracture, reducing floatation and increasing density. Elemental analysis, including surface phase composition and cross-sectional distribution, confirmed the successful ion exchange of Na⁺ and K⁺. Increased densification of the HGMs formed a compressive stress layer on their thin walls, inhibiting crack extension and enhancing compressive strength. Overall, adjusting ion exchange parameters improved the compressive strength of HGMs, making them suitable for high-performance applications in aerospace, automotive, and marine engineering. Future efforts will aim to reduce costs or incorporate acid etching to improve surface stability and minimize material loss during strengthening.
期刊介绍:
Construction and Building Materials offers an international platform for sharing innovative and original research and development in the realm of construction and building materials, along with their practical applications in new projects and repair practices. The journal publishes a diverse array of pioneering research and application papers, detailing laboratory investigations and, to a limited extent, numerical analyses or reports on full-scale projects. Multi-part papers are discouraged.
Additionally, Construction and Building Materials features comprehensive case studies and insightful review articles that contribute to new insights in the field. Our focus is on papers related to construction materials, excluding those on structural engineering, geotechnics, and unbound highway layers. Covered materials and technologies encompass cement, concrete reinforcement, bricks and mortars, additives, corrosion technology, ceramics, timber, steel, polymers, glass fibers, recycled materials, bamboo, rammed earth, non-conventional building materials, bituminous materials, and applications in railway materials.