In this study,the effects of five different ionic and nonionic surfactants on the physical properties and microstructures of a metakaolin-based geopolymer(MKG)were investigated.It is the first comprehensive comparativ...In this study,the effects of five different ionic and nonionic surfactants on the physical properties and microstructures of a metakaolin-based geopolymer(MKG)were investigated.It is the first comprehensive comparative study of the effects of sodium lauryl sulfonate(SLS),alkyl polyglycoside(APG),benzalkonium chloride(BAC),sucrose fatty acid esters(SE),and stearic acid(STA)on MKG.Viscosity,densities,apparent water absorption,and compressive strength were measured,and pore structures,micro-defects,and gels observed through scanning electron microscopy(SEM)and mercury intrusion porosimetry(MIP).In the MKG slurry,a high affinity of surfactants to liquid-air interfaces increased viscosity and promoted the generation of bubbles.Based on both the ionic types and molecular configurations of the surfactants,stronger adsorption of a surfactant on the surface of the metakaolin resulted in better dispersion of metakaolin particles and a denser microstructure of the MKG.The surfactants with weaker adsorption(SLS and APG)caused higher porosity,a larger pore size,and more micro-defects,while those with stronger adsorption(BAC,SE,and STA)led to relatively lower porosity and denser microstructures.Density,water absorption,and compressive strength were closely related to the total intrusion porosity of the MKG.The mechanisms underlying surfactant adsorption to the surface of metakaolin are proposed.展开更多
Metakaolin-based geopolymer materials reinforced with sand in tubular shape were developed, and their durability in acidic, neutral and humid environment was investigated. Results show that mechanical properties of ma...Metakaolin-based geopolymer materials reinforced with sand in tubular shape were developed, and their durability in acidic, neutral and humid environment was investigated. Results show that mechanical properties of materials are not affected by durability tests suggesting a good stability in aqueous media. Furthermore, the surface of samples which was covered by soluble species such as KOH or K2CO3 becomes smooth after treatment in acidic and neutral media and appears not to be attacked confirming the high acid resistance of geopolymer materials.展开更多
基金Project supported by the National Key R&D Program of China(No.2018YFB0605700)the National Natural Science Foundation of China(Nos.51879230 and 51978608)。
文摘In this study,the effects of five different ionic and nonionic surfactants on the physical properties and microstructures of a metakaolin-based geopolymer(MKG)were investigated.It is the first comprehensive comparative study of the effects of sodium lauryl sulfonate(SLS),alkyl polyglycoside(APG),benzalkonium chloride(BAC),sucrose fatty acid esters(SE),and stearic acid(STA)on MKG.Viscosity,densities,apparent water absorption,and compressive strength were measured,and pore structures,micro-defects,and gels observed through scanning electron microscopy(SEM)and mercury intrusion porosimetry(MIP).In the MKG slurry,a high affinity of surfactants to liquid-air interfaces increased viscosity and promoted the generation of bubbles.Based on both the ionic types and molecular configurations of the surfactants,stronger adsorption of a surfactant on the surface of the metakaolin resulted in better dispersion of metakaolin particles and a denser microstructure of the MKG.The surfactants with weaker adsorption(SLS and APG)caused higher porosity,a larger pore size,and more micro-defects,while those with stronger adsorption(BAC,SE,and STA)led to relatively lower porosity and denser microstructures.Density,water absorption,and compressive strength were closely related to the total intrusion porosity of the MKG.The mechanisms underlying surfactant adsorption to the surface of metakaolin are proposed.
文摘Metakaolin-based geopolymer materials reinforced with sand in tubular shape were developed, and their durability in acidic, neutral and humid environment was investigated. Results show that mechanical properties of materials are not affected by durability tests suggesting a good stability in aqueous media. Furthermore, the surface of samples which was covered by soluble species such as KOH or K2CO3 becomes smooth after treatment in acidic and neutral media and appears not to be attacked confirming the high acid resistance of geopolymer materials.
