Low temperature alkaline activation of weathered fly ash: Influence of mineral admixtures on early age performance

被引:63
作者
Messina, Francesco [1 ]
Ferone, Claudio
Colangelo, Francesco
Cioffi, Raffaele
机构
[1] Univ Napoli Parthenope, Dept Engn, Ctr Direz, I-80143 Naples, Italy
关键词
Alkali activated binders; Weathered fly ash; Blast furnace slag; Silica fume; Metakaolin; Early-age behavior; DENSIFIED SILICA-FUME; COMPRESSIVE STRENGTH; QUANTITATIVE-DETERMINATION; CEMENTITIOUS SYSTEMS; PORTLAND-CEMENT; PART II; GEOPOLYMER; SLAG; REACTIVITY; CONCRETE;
D O I
10.1016/j.conbuildmat.2015.02.069
中图分类号
TU [建筑科学];
学科分类号
0813 ;
摘要
In the field of alkali activated materials, weathered fly ash represents a scarcely explored edge, since most of the studies related to alkali activated fly ash use qualified/highly reactive samples. In this work, early-age behavior of several binary alkali activated binders was assessed in terms of workability, chemical shrinkage, strength development and ultrasonic pulse velocity. The mineral admixtures in the binary systems were blast furnace slag, silica fume and metakaolin. Curing temperature was fixed at 20 degrees C, in opposition to most literature studies that focused on more energy-intensive curing conditions. An efficiency index was defined and calculated in order to synthesize all the results and compare the binders. Silica fume addition did not determine performance improvement even at significant mass percentages (up to 15%). Metakaolin improved significantly the mechanical performance but reduced excessively the paste flowability. Blast furnace slag revealed to be the most effective secondary component, since this system was able to develop a highly promising mechanical performance and exhibit a satisfactory flowability and low early age shrinkage. (C) 2015 Elsevier Ltd. Al rights reserved.
引用
收藏
页码:169 / 177
页数:9
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