CONSTRUCTION AND BUILDING MATERIALS
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2018
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IF 3.485
Fubing Zou,Hongbo Tan,Xingyang He,Baoguo Ma,Xiufeng Deng,Ting Zhang,Junpeng Mei,Xiaohai Liu,Huahui Qi
Fly ash (FA) has been accepted as one of the most popular supplementary material in blends with cement. However, high content of FA added would result in very slow strength development at the early age, and this problem limits the use of FA in precast concrete. In this study, an attempt was made to enhance the early strength of steam-cured high content cement-fly ash paste (SCHF, 50% FA) by incorporating triisopropanolamine (TIPA), and the underlying mechanism was systematically investigated in terms of hydration products, pore structure, and ions dissolution of FA. The early hydration process was assessed with isothermal calorimetry, thermogravimetric with differential thermo-gravimetric, and scanning electron microscopy with energy dispersive spectrometer. The pore structure of hardened paste was characterized with mercury intrusion porosimetry. The solubility of FA was analyzed with inductive coupled plasma emission spectrometer, nuclear magnetic resonance, and scanning electron microscopy. The chelating ability of TIPA with Fe 3+ and Al 3+ was evaluated with the conductivity. These results show that with the dosage of TIPA less than 0.10%, the compressive strength will increase with increasing dosage of TIPA, mainly because of the acceleration of both hydration of cement and pozzolanic reaction of FA; while with the dosage more than 0.10%, the compressive strength was sharply decreased owing to its air-entraining effect to increase the harmful pores, with negative effect on mechanical performance. The reason for the accelerated pozzolanic reaction of FA is that TIPA can accelerate the dissolution of aluminum, ferric and silicate into solution to participate in hydration. The findings are expected to provide guidance on promoting the use of FA in precast concrete.
研究领域:
土木工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
·
2025
·Vol. 40
·期 1
·130-140
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IF 1.1
Liu Jian,Chen Meiting,Ji Xiaoli,Xu Chao,Wang Chunmei
A ternary early-strengthening agent consisting of calcium formate + triethanolamine + lithium sulfate was compounded with quercetin to shorten the setting time of cementitious materials while ensuring their early strength. The optimum ratio of the three early-strengthening agents was determined as 0.5% calcium formate + 0.04% triethanolamine + 0.4% lithium sulfate by response surface methodology. The effects of the ternary early-strengthening agent composed of calcium formate + triethanolamine(TEA)+ lithium sulfate on cementitious pore sealing materials under the synergistic effect of quercetin were studied by means of the performance tests of compressive strength, fluidity, and setting time, and the microstructural characterizations of X-ray powder diffractometer(XRD), thermogravimetry (TG-DSC) and scanning electron microscopy (SEM). The study shows that the synergistic effect of ternary early-strengthening agent and quercetin forms a multiperformance composite admixture for cementitious materials. The best performance was obtained with the compounding scheme of 0.5% calcium formate + 0.04% triethanolamine + 0.4% lithium sulfate ternary early-strengthening agent and 0.05% quercetin. The compressive strength of 1, 3, 7, and 28 d are 94.8%, 39.8%, 42%, and 28% higher than those of the blank group, respectively. The initial time and final setting time are 41 and 57 minutes, respectively. According to the microscopic analysis, the network and fibrous C-S-H gels generated by ternary early-strengthening agents are attached to the surface promoted by quercetin, which forms skeleton support while thickening and solidifying the cement slurry, which enhances the early compressive strength of the cement-based materials.
研究领域:
建筑材料学
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化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2019
·
IF 4.046
Chuanqing Fu,Hailong Ye,Aoke Lei,Guojun Yang,Pan Wan
In this work, the poly(sodium-acrylate acrylamide) superabsorbent polymer (SAP) composites reinforced with micro silica and kaolin clay particles are evaluated as novel additives to control and improve the fresh and hardened properties of alkali-activated slag (AAS). The water swelling and retention capacity of plain and modified SAPs in various solutions pertinent to AAS binder systems (including deionized water, saturated Ca(OH) 2 , 1.0 M NaOH, 0.5 M Na 2 CO 3 , and 0.5 M Na 2 SO 4 ) are studied using the gravimetric ‘tea bag’ and thermogravimetric methods, together with molecular analysis. The results show that the use of micro silica and kaolin clay-reinforced SAP composites slightly alleviates the negative influence of conventional SAP counterparts on the flowability, setting, and early-age compressive strength of AAS pastes. Nevertheless, the addition of SAP composites merely postpones the early-stage drying shrinkage development but tends to increase the long-term deformation of hardened AAS in unsealed conditions, likely due to the reduced bulk stiffness with enlarged porosity.
研究领域:
建筑材料学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2025
·
IF 8
Haochuan Wang,Xin Liu,Hui Xie,Chong Wang,Wei Wang,Jinxiang Hong,Pan Feng
The poor dispersion of nano-SiO₂ in shotcrete systems limits its effectiveness and can even lead to detrimental effects. To address this issue, ettringite suspension was introduced as a novel dispersion carrier. Nano-SiO₂ was found to physically adsorb onto ettringite crystals, significantly improving its spatial distribution without organic dispersants. Compared to direct nano-SiO₂ addition, the incorporation of ettringite—especially via premixing—markedly enhanced performance. With premixed nano-SiO₂ and ettringite, and nano-SiO₂ content ranging from 0.25 % to 1 %, the 6-hour compressive strength increased by 93∼600 %, while the initial and final setting times were reduced by 46∼79 % and 47∼91 %, respectively, compared to the control. Isothermal calorimetry, quantitative X-ray diffraction (QXRD), and thermogravimetric analysis (TG) confirmed that the well-dispersed nano-SiO₂ accelerates early cement hydration by providing abundant nucleation sites facilitating rapid formation of hydration products, mainly calcium silicate hydrate (C–S–H). Simultaneously, ettringite acts not only as a dispersant but also strengthens the early-age framework, enhancing load transfer within the shotcrete matrix.
研究领域:
建筑材料学
·
水泥基材料
·
混凝土技术
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纳米材料应用
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土木工程材料
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2020
·
IF 4.419
Guoxin Li,Qingfeng Liu,Mengdie Niu,Li Cao,Bing Nan,Chen Shi
Nanosilica (NS) with ultra-fine structure and high pozzolanic activity frequently used to reinforce cement-based materials. In this study, NS was selected to modify CSA-OPC blends to meet the critical engineering properties of rapid repair materials, such as fast setting hardening, high early strength and sustainable late strength. The effects of NS on the setting time, mechanical strength, phase and mass change of hydrates and pore structure of binary blends were investigated. Results indicated that NS largely shortens the setting time. The remarkable enhancement in the early strength compared to other substitution levels by adding 1.0wt. %NS, and the sustainable late strength was maintained. XRD and TG-DTA demonstrate that ettringite was the main hydrate and its content evidently increase with the inclusion of NS. Furthermore, SEM micrographs was observed that NS effectively improves the binding between the hydrates. The utilization of NS resulted in less porosity and more homogeneous binary mortar as seen in MIP test.
研究领域:
土木工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
CEMENT AND CONCRETE RESEARCH
·
2022
·
IF 11.958
Weipeng Feng,Yu Jin,Dapeng Zheng,Yuan Fang,Zhijun Dong,Hongzhi Cui
This study investigates the role of triethanolamine (TEA) in regulating the early strength of ultra-lightweight (∼460 kg/cm 3 ) fly ash-based chemically foamed geopolymer . The reaction kinetics, pore distribution and skeleton strength were examined using isothermal calorimetry , X-ray microtomography, and solid-state nuclear magnetic resonance spectroscopy , respectively. The three-dimensional pore spatial distribution patterns were statistically assessed by applying the Nearest-neighbor distance-based techniques. The results showed that TEA can regulate the early strength of geopolymer foam by rendering homogeneous pore sizes and spatial distributions even when the geopolymerization of the skeleton is retarded. Furthermore, 0.3 % TEA reduced the compressive strength of the skeleton by 13.4 %, from 105.8 MPa to 91.6 MPa, but doubled the specific strength of the geopolymer foam from 2271 N·m/kg to 4662 N·m/kg. The proposed mechanism suggests that foaming kinetics can be regulated for a homogeneous pore distribution by manipulating the complexing effect.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2023
·
IF 2.2
Jiantong Dong,Shihao Yang,Deyong Sun,Zhiyong Liu,Yuanliang Xiong
The rapid development of subway and prefabricated building industry, along with the adoption of the “dual carbon” strategy, have put forward higher demands on early strength, environmental protection and high efficiency for precast concrete products and concrete segments. In this study, a ultra-early strength type polycarboxylate superplasticizer (ES) was synthesized successfully by a design molecule structure such as introducting ultra long polyoxyethlene side chains, functional monomer (2-acrylamide-2-methylpropanesulfonic acid), and cationic monomer (Methacrylatoethyl trimethyl ammonium chloride) composition. Discovered through performance testing, the dispersion capacity of ES firstly are increased and then decreased with increasing the acid-ether ratio, and the same trend as the compressive strength harden concrete with ES at the age of 1, 3, and 7 days. The sulfonate groups and cationic monomers into molecular structure, they have little effect on the dispersion capacity, but the compressive strength of concrete at the age of 1, 3, and 7 days get improved. Through camparative study in the setting time of concrete and compressive strength of concrete between ES and an engineering application product SX. The results show that addition of ES does not retard cement hydration, and accelerates the coagulation of cement. Moreover, the compressive strength of concrete is better than SX at all ages, its further verified with X-ray diffraction and Scanning electron microscopy. This study indicates that rational design of molecular structure through the introduction of ultra-long side chains and functional monomers can maximize the early strength performance of polycarboxylate superplasticizer without affecting later strength development.
研究领域:
建筑材料学
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化学工程
·
土木工程
✓ 已验证
产品关联
DOI
高影响因子
POWDER TECHNOLOGY
·
2022
·
IF 5.64
Hao Zhang,Jue Kou,Chunbao Sun,Peilong Wang,Jiawei Lin,Jinlin Li,Yongliang Jiang
Pb(II)-containing tailings are serious hazards to the environment. Their rationalization and harmless treatment are of great significance to the construction of the green mine. Cemented paste backfill (CPB) plays an important role in the large-scale disposal of tailings. However, Pb(II) in tailings harms the hydration reaction of ordinary Portland cement (OPC), thus reducing the early strength of CPB. The smooth running of mining was hampered. Besides, CPB is also essential for the effective immobilization of Pb(II). In this study, carbon nanotubes (CNTs) were used to optimize the properties of CPB. The influence of CNTs on OPC hydration and the phase composition of hydration products were studied by isothermal calorimeter test, X-Ray diffraction, and thermogravimetry analysis. The property changes of CPB, including flowability and strength development, caused by CNTs were investigated. The hydration of OPC was accelerated when CNTs were added. And more hydration gels generated to form a more compact structure of CPB. Due to the denser structure and more hydration gels caused by the CNTs, as well as the adsorption of Pb(II) on CNTs, the early strength of CPB was improved. And the Pb(II) immobilization was enhanced.
研究领域:
环境工程
·
材料科学
·
矿业工程
·
固体废物处理
·
重金属污染控制
·
可持续采矿
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）