Journal ArticleDOI
The role of fly ash microsphere in the microstructure and macroscopic properties of high-strength concrete
TLDR
In this paper, a fly ash microsphere collected directly from a high-temperature furnace using ceramic dust tubes to high-strength concrete, and with silica fume as a control admixture, investigated the effects of FAM on the hydration and hardening processes of the cementitious materials and the macroscopic properties of the high strength concrete.Abstract:
This study applied a type of fly ash microsphere (FAM) collected directly from a high-temperature furnace using ceramic dust tubes to high-strength concrete, and with silica fume as a control admixture, investigated the effects of FAM on the hydration and hardening processes of the cementitious materials and the macroscopic properties of the high-strength concrete. Two cement replacement levels (8% and 15%) and two water-to-binder (W/B) ratios (0.35 and 0.25) were utilized. The results show that FAM has a relatively high level of early activity; SEM images indicate that a significant portion of the FAM reacted at early ages in the cement-FAM hardened paste. Though the early activity of FAM is lower than that of silica fume, the cement-FAM complex binder has similar hydration properties with the cement-silica fume complex binder. At 90 d, FAM consumed less Ca(OH) 2 than silica fume and a significant amount of unreacted FAM remained in the hardened pastes. The contributions of FAM to the pore structure of the hardened pastes are lower than those of silica fume at early ages; however, FAM can significantly improve pore structure at late ages, similar to silica fume. In addition, FAM can improve the flowability, late-age strength, and permeability to chloride ions of concrete, while decreasing early-age autogenous shrinkage.read more
Citations
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Journal ArticleDOI
Green concrete: Prospects and challenges
TL;DR: The increasing demand for green concrete has been spurred by demand for high quality concrete products, desire of nations to reduce green-house gas emission, need for conservation of natural resources and limited landfill spaces as mentioned in this paper.
Journal ArticleDOI
Prediction of mechanical properties of green concrete incorporating waste foundry sand based on gene expression programming.
Muhammad Farjad Iqbal,Qing-feng Liu,Iftikhar Azim,Xingyi Zhu,Jian Yang,Muhammad Faisal Javed,Momina Rauf +6 more
TL;DR: Gen expression programming (GEP) has been employed in this study to develop empirical models for prediction of mechanical properties of concrete made with WFS (CMWFS), which can enhance the re-usage of WFS for development of green concrete leading to environmental protection and monetary benefits.
Journal ArticleDOI
Effect of fly ash microsphere on the rheology and microstructure of alkali-activated fly ash/slag pastes
TL;DR: In this article, a fly ash microsphere (FAM) is used to reduce the internal friction between fly ash and slag grains and mitigate the agglomeration of flocs and fragmentation to release the locked water.
Journal ArticleDOI
Eco-friendly treatment of low-calcium coal fly ash for high pozzolanic reactivity: A step towards waste utilization in sustainable building material
Jin Yang,Huang Jianxiang,Ying Su,Xingyang He,Hongbo Tan,Wei Yang,Bohumír Strnadel,Bohumír Strnadel +7 more
TL;DR: In this article, a wet-milling treatment was used to activate coal fly ash and promote its sustainable utilization. But the results showed that the pozzolanic reactivity of fly ash is greatly improved after wetmilling, as high as 140% at 60 days.
Journal ArticleDOI
Fractal dimension of concrete incorporating silica fume and its correlations to pore structure, strength and permeability
TL;DR: In this paper, the authors focused on the correlations among the fractal dimension, compressive strength, and permeability of concrete incorporating silica fume, and calculated fractal dimensions from SEM images by using a box-counting method.
References
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Book
Concrete: Microstructure, Properties, and Materials
P.K. Mehta,Paulo J.M. Monteiro +1 more
TL;DR: Concrete: Microstructure, Properties, and Materials as mentioned in this paper provides complete details on the microstructure-property relationship approach to provide scientific explanation for the strength and durability of concrete.
Journal ArticleDOI
Supplementary cementitious materials
TL;DR: The use of silica-rich SCMs influences the amount and kind of hydrates formed and thus the volume, the porosity and finally the durability of these materials.
Journal ArticleDOI
The geopolymerisation of alumino-silicate minerals
Hua Xu,J.S.J. van Deventer +1 more
TL;DR: In this paper, the effect of mineral properties on the compressive strength of the synthesized geopolymer was investigated, and it was shown that a wide range of natural Al-Si minerals could serve as potential source materials for the synthesis of geopolymers.
Journal ArticleDOI
The coexistence of geopolymeric gel and calcium silicate hydrate at the early stage of alkaline activation
TL;DR: In this paper, the effects of ground granulated blast furnace slag (GGBFS) on the microstructure and mechanical properties of metakaolin (MK) based geopolymers were studied.