Recycling
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2023
·Vol. 8
·期 5
·68
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IF 4.3
Austen Rowell,Tewodros Ghebrab,Randall Jeter
Microbial treatment of recycled concrete aggregate (RCA) may improve the quality of the aggregate, and enhance its use in the production of structural concrete and promote the recycling of concrete waste. The mortar phase of the RCA is responsible for the poor performance of the aggregate. Treating the old adhered mortar or removing it from the natural aggregate (NA) is an option to make RCA beneficial for the production of quality recycled aggregate concrete (RAC). Removing the adhered mortar from recycled concrete aggregate using silicate-solubilizing bacteria was investigated. The bacteria could synthesize the silicates in the calcium silicate hydrate phase of the cement paste leading to the breakdown of the old adhered mortar. Four SSB strains were tested for survivability and activity in an alkaline medium to simulate the concrete environment. TheSerratia marcescensbacterial strain, which survived the environment, was inoculated into screw-cap glass vials containing recycled concrete aggregate fragments and glucose-enhanced nutrient broth and then incubated for 14 days. Partial removal of the old adhered mortar was observed based on the weight lost from the RCA. TheS. marcescensbacterial strain could survive the alkaline concrete environment and solubilize the silicates present in cement paste resulting in the removal of the old adhered mortar.Keywords:recycled concrete aggregate;silicate-solubilizing bacteria;recycled aggregate concrete;Serratia marcescens;old adhered mortar
研究领域:
微生物学
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土木工程
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材料科学
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DOI
高影响因子
CEMENT & CONCRETE COMPOSITES
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2022
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IF 9.93
Yiming Zhou,Mohamed Elchalakani,Peng Du,Chuanzhi Sun,Zuhua Zhang,Hao Wang
Using capsules containing repairing materials to heal concrete cracks has always been a method of great interest to achieve self-healing concrete. Breaking the capsules to release repairing materials is a challenging task. The current methods used to break capsules mainly rely on instant external forces, which implies that slowly developing cracks cannot be healed by capsules. In this paper, we present a novel photocatalytic self-healing mortar to solve this problem. To do so, NaHCO 3 , Ca(OH) 2 and citric acid are inserted into macro capsules. Then, the photocatalyst TiO 2 is added to the insoluble shells of capsules to allow them to be broken by sunlight. After shells of capsules are degraded by sunlight, NaHCO 3 , Ca(OH) 2 and citric acid react in a wet environment to generate repairing materials that fill the cracks. To support the feasibility of the idea, physical and chemical experiments and characterization studies were conducted. Two-millimetre wide mortar cracks can be healed by the substances released from the photocatalytic capsules. The results of water permeability tests show that the two photocatalytic capsules can reach 52% healing efficiency. The characterization results show that the substances filling the cracks are unreacted NaHCO 3 , Ca(OH) 2 , citric acid and insoluble products of calcium salts. Our results suggest that sunlight can be used for the self-healing of mortar.
研究领域:
土木工程
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材料科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
Heliyon
·
2024
·
IF 3.4
Yuanyuan Meng,Shuangxi Li,Zhi Zhang
Corrosion inhibitors play a vital role in impeding the corrosion process of steel bars within concrete structures exposed to corrosive environments. Nevertheless, conventional corrosion inhibitors pose environmental risks. In contrast, contemporary studies have explored corrosion inhibitors that are eco-friendly. However, these inhibitors are burdened by high costs and complex production processes, impeding the widespread application in concrete structures. Consequently, this study presents an innovative solution by incorporating uniconazole, an agricultural fungicide, as a corrosion inhibitor for steel bars in concrete structures. The steel bars were exposed to corrosion within a simulated concrete pore solution containing 0.6 mol/L NaCl, both with and without the presence of uniconazole. The morphology and hydrophilicity of the steel bar surface were investigated via optical microscope and contact angle experiments. Electrochemical tests (open circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopy, and Mott-Schottky analysis) and X-ray photoelectron spectroscopy were employed to investigate the corrosion inhibition performance and mechanism of uniconazole. The results demonstrate that uniconazole elevates the hydrophobicity and contributes to the corrosion inhibition of steel bars. Electrochemical test results indicate that as the concentration of uniconazole increases from 1 × 10 −4 mol/L to 1 × 10 −3 mol/L, the inhibition efficiency likewise demonstrates a corresponding increase, escalating from around 50 %–90 %. Uniconazole molecules function as mixed-type inhibitors, exhibiting characteristics of both anode-type and cathode-type inhibitors. The adsorption of uniconazole enhances the stability and thickness of the passive-adsorbed layer on the steel surface, effectively impeding the charge transfer process and obstructing the interaction of corrosive substances with the base metal. In summary, the application of uniconazole exhibits the highlights of efficient, cost-effective, environmentally friendly, and the potential for scalable production. This positions uniconazole as a promising candidate for use as a corrosion inhibitor in the domain of concrete structures.
研究领域:
土木工程
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材料科学
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环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Xicheng Wang,Shucheng Yuan,Caobin Wu,Xiao Sun,Shougang Chen,Qingguo Wang
The removal of tetracycline (TC) from wastewater was a necessity due to the overuse of antibiotics and its deleterious effects on the environment. In this study, an adsorbent for the removal of tetracycline was prepared by modifying waste concrete powder using a straightforward iron (iii) chloride (FeCl 3 ) precipitation method. The structure of the prepared material was characterized using a scanning electron microscope(SEM), a specific surface area and pore size analyzer (BET), a Fourier transform infrared spectroscopy(FTIR), an X-ray diffractometer (XRD), and an X-ray photoelectron spectroscopy (XPS). The characterization results demonstrated that amorphous iron (iii) hydroxyl oxides were successfully loaded onto concrete powder. The modified concrete powder exhibited a porous structure, with a notable increase in specific surface area from 12.8 m²/g to 111.5 m²/g and a substantial rise in pore volume from 0.052 cm³ /g to 0.107 cm³ /g. The results of the batch adsorption experiments demonstrated that the adsorbent exhibited a high removal rate of tetracycline, reaching 83.3 % at pH of 4, a dosage of 2 g/L, a temperature of 25°C, and a TC concentration of 10 mg /L. Furthermore, the effects of the initial pH of the solution, the dosage of the adsorbent, and the presence of co-existing ions on the adsorption of tetracycline from modified concrete powder were investigated. The adsorption kinetics revealed that the pseudo-second-order model was more consistent with the adsorption behavior, while the adsorption isotherms indicated that the Freundlich model was more suitable than the Langmuir model. Moreover, an examination of the thermodynamic outcomes substantiated that the adsorption was spontaneous, and endothermic. The primary mechanisms of TC removal by modified concrete powder are electrostatic attraction, hydrogen bonding interactions, pore-filling effects, and surface complexation. This study presented a convenient, effective, and potentially profitable method for the construction of adsorbents with low-cost to remove TC from wastewater.
研究领域:
环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
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2017
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IF 0
D. Martemianov,B.-B. Xie,T. Yurmazova,M. Khaskelberg,F. Wang,C.-H. Wei,S. Preis
Aqueous arsenic and heavy metals in concentrations exceeding sanitary limits present an acute regional problem. Adsorption is an effective although costly method of pollutants removal. This makes the search for low-cost effective disposable adsorbents necessary. The adsorbents using vermiculite concrete and aerated autoclaved light concrete (aerocrete) modified with iron oxyhydroxide were synthesized and studied. The specimens of adsorbent materials showed the adsorption capacity more than two-fold exceeding the vermiculite-based adsorbents in respect to copper and lead cations, 53 and 195 mg g −1 , respectively, having the adsorption capacity for cadmium comparable to exfoliated vermiculite at 35.5 mg g −1 . Arsenic anions were adsorbed in amounts comparable to the ones of carbon composites-supported ferric oxyhydroxide adsorbents, up to 16 mg g −1 of arsenate. The analysis of adsorption dependent on temperature showed its spontaneous low-energy ion-exchange character. Desorption of heavy metals and arsenic anions from used adsorbents meets the requirements of drinking water standards with the exception of cadmium, meeting the agricultural use standard of 0.01 mg L −1 . The new synthetic adsorbents were found to be cost-efficient, safe and reliable in removal of arsenic anions and heavy metals cations.
研究领域:
环境科学
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材料科学
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产品关联
DOI
Materials
·
2022
·Vol. 15
·期 21
·7492
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IF 3.748
Min Qiao,Jingzhi Wu,Nanxiao Gao,Guangcheng Shan,Fei Shen,Jian Chen,Bosong Zhu
In this study, a series of polyether-type defoamers for concrete which consist of the same alkyl chain (hydrophobic part) but different polyether chains (hydrophilic part) was prepared, and the structure–property relationship of the defoamers was investigated for the first time. Using oleyl alcohol (OA) as the starting agent (alkyl chain), the polyether defoamers with different polyether chains were prepared by changing the amount and sequence of ethylene oxide (EO) and propylene oxide (PO) units. The properties of different defoamers were tested in aqueous solutions, and fresh and hardened mortars; the structure–property relationship of the defoamers was thus studied. The results indicated that the defoaming capacity of the polyether defoamers decreased with an increased EO amount, and the defoamers linked with both EO and PO units (PO before EO) had a stronger defoaming capacity than those linked with EO only. This study is beneficial for the development and applications of novel synthetic polyether-type defoamers for concrete.Keywords:polyether;defoamer;bubble;air void;mortar;concrete
研究领域:
建筑材料学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
DIAMOND AND RELATED MATERIALS
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2022
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IF 3.806
Xiaoyi Zhang,Guoliang Lin,Shenglan Ma,Mingyi Liu,Wanxi Jiang,Chen Wu
This article has been retracted: please see Elsevier Policy on Article Withdrawal ( http://www.elsevier.com/locate/withdrawalpolicy ). This article has been retracted at the request of the Corresponding Authors and Editor-in-Chief. One of the corresponding authors, Xiaoyi Zhang, notified the journal of several issues relating to the article and requested its retraction. These issues have been detailed below: - The experiments were not performed as reported in the article. Specifically, the coating was applied to a wood surface, rather than the reported concrete surface. When subsequent experiments were conducted using concrete, the experimental data were not reproducible. - Some of the authors informed the journal that they were not aware of the content of the manuscript, nor of their authorship. - In addition, according to Dr. Zhang: “…the pictures and data in the paper are used incorrectly, resulting in unreliable experimental results”. These issues represent a clear violation of our publishing policies, and publishing ethics standards. The Editor-in-Chief has assessed the case and decided to retract the article. The corresponding authors agreed to the retraction.
研究领域:
材料科学
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土木工程
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化学
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
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2025
·
IF 8
Mingzheng Zhu,Sizhe Xue,Jixiang Zhu,Muhammad Riaz Ahmad,Jian-Guo Dai
Geopolymer concrete has emerged as a promising eco-friendly alternative to conventional cementitious materials, particularly for sustainable underwater engineering applications. However, its inherent brittleness limits its broader use in such environments. To address this challenge, this study developed and evaluated an innovative underwater ultra-high-performance geopolymer concrete (U-UHPGC). The effects of varying water-to-precursor (w/p) ratios (0.33, 0.30, and 0.27) and two fly ash (FA) to ground granulated blast furnace slag (GGBFS) ratios (5:5 and 2:8) on the anti-washout resistance, rheological behavior, mechanical performance, and microstructural characteristics of U-UHPGC were systematically investigated. The results revealed that lower w/p ratios and higher GGBFS contents significantly enhanced the yield stress and plastic viscosity of the paste, thereby improving its resistance to washout in underwater conditions. Furthermore, the optimized mix design achieved compressive and flexural strengths of up to 81.84 MPa and 12.83 MPa, respectively, alongside excellent flexural deformation capacity. Microstructural analysis demonstrated that reduced w/p ratios and increased GGBFS content led to a denser matrix, promoting stronger interfacial bonding between polypropylene fibers and the matrix. This enhanced bonding allowed the fibers to effectively bridge and arrest cracks. As a key environmental advantage, the U-UHPGC formulation embodies a substantial reduction approximately 40 % in both energy demand and carbon footprint over traditional U-UHPC. These findings contribute valuable insights for the advancement of high-performance geopolymer concretes tailored for durable and sustainable marine infrastructure.
✓ 已验证
产品关联
DOI
高影响因子
Journal of Building Engineering
·
2025
·
IF 7.4
Zhenxing Du,Chenglong Li,Penggang Wang,Zuquan Jin,Li Tian,Aoshen Wang,Min Zhang
To overcome limitations of single-trigger self-healing systems, this study developed microcapsules (MCs) responsive to both mechanical stress and chloride ions for marine concrete repair. Ethyl cellulose/nano-silica shells encapsulating epoxy resin were synthesized via solvent evaporation method, with PbSO 4 embedded for chloride activation. MCs exhibited optimal size (70–120 μm), thermal stability (>190 °C), and homogeneous PbSO 4 distribution. Increasing PbSO 4 content enhanced chloride responsiveness, forming pores that released healing agent via osmotic pressure, while improving MC stiffness. Additionally, the self-healing mortars demonstrate notable strength recovery, with the highest healing rate of 126.30 % under standard curing and 114.50 % under seawater curing, reflecting the MCs' robust performance in aggressive environments. Cracks up to 229.7 μm width were effectively healed within 7 days, with healing efficiency positively correlating with PbSO 4 content. The porosity reduction rate rose with the increase in PbSO4 dosage, reducing porosity by 9.42 %–26.71 % post-healing. Additionally, MC significantly enhanced the chloride ion permeability resistance of self-healing mortars, achieving a reduction rate of 67.37 %–84.90 %. This d ual-trigger system provides targeted, efficient self-healing for marine concrete infrastructure, significantly enhancing durability.
研究领域:
材料科学
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土木工程
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建筑材料
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腐蚀防护
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智能材料
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结构耐久性
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2024
·
IF 7.4
Zhaokuan Cui,Hui Zhao,Jiale Song,Wei Liu,Shuheng Zhang,Weiguang Li
Surface treatment protective technology is a cost-effective approach to prevent harmful ions from infiltrating concrete, avoiding the deterioration of performance and increasing longevity. Here, a novel coupling agent with ester group (MA-KH-550) is synthesized from γ-aminopropyltriethoxysilane (KH-550) and methyl acrylate (MA) to modify nano-SiO 2 particles. Subsequently, the ester-modified nano-SiO 2 can be successfully dispersed in alkaline composite silicate solutions to fabricate nano-SiO 2 /silicate coatings, improving the impermeability of concrete. The incorporation of nano-SiO 2 particles can fill microscopic pores in cementitious materials, which improves the compactness of the concrete. Furthermore, nano-SiO 2 particles can also accelerate secondary hydration of cement and synergistically generate more calcium silicate hydrate gel with silicates to further boost the compactness of the concrete. High-compactness coatings reduce the penetration of the medium, thereby enhancing the impermeability performance of the concrete. When the nano-SiO 2 particle content is 1.0 wt%, the optimal performance of concrete is achieved. Compared with the original C30 concrete, the C30 concrete treated with the nano-SiO 2 /composite silicate (nano-SiO 2 /CSC) shows a 31.1 % decrease in chloride ion resistance, a 35.5 % reduction in carbonization resistance, a loss rate of 1.08 % for anti-freezing quality. This work charts a new course for designing and developing high-performance composite silicate coatings for concrete.
研究领域:
材料科学
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土木工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Building Engineering
·
2024
·
IF 6.7
Chengtian Zhu,Biqin Dong,Georgy Lazorenko,Guohao Fang,Yanshuai Wang,Jiandong Zuo
During the manufacturing of foam concrete, conventional chemical and physical foaming methods are still inadequate for regulating and stabilizing the bubble properties. In this work, a one-pot method, denoted as in-situ mechanical frothing, was proposed preparing foam concrete by vigorously stirring the mixture of water, cement, sandy soil, and foaming agent. Sandy soil (SS) was used in the content range of 25–75 % as cement replacement to decrease the binder consumption and reduce costs. The influence of in-situ mechanical frothing technology and SS dosage on the properties of paste rheology, pore structure , compressive strength , and thermal properties was investigated. The results showed that the average pore size of foam concrete prepared by this method is between 45.73 and 74.58 μm. The compressive strength of the formed foam concrete at dry density of 600–1000 kg/cm 3 was 2.78–16.37 MPa, which was 85%–231 % higher than that the standard values. The incorporation of SS resulted in smaller and homogeneous pore structure in foam concrete. Moreover, foam concrete with 25–75 % SS dosage showed 7–40 % decrease in thermal conductivity . The overall analysis showed that the 25–50 % S S-incorporated foam concrete enabled achieving higher standard properties through in-situ mechanical frothing.
研究领域:
建筑材料学
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土木工程
✓ 已验证
产品关联
DOI
高影响因子
CONSTRUCTION AND BUILDING MATERIALS
·
2021
·
IF 6.141
Li Hou,Jun Li,Zhongyuan Lu,Yunhui Niu
Foaming agent is an indispensable component in preparation of foam concrete by using prefabricated foams. In this study, four types of foaming agents were used to prepare foam concrete. Effect of foaming agent on properties of fresh and hardened foam concrete, interaction between foaming agent and cement, and the gas–liquid interface in foam concrete were studied. It is observed that the interaction between foaming agent and cement played a greater role in the formation process of foam concrete. The property of gas–liquid interface of foam concrete was the most important factor for the performance of in foam concrete, which determined the stability of fresh foam concrete, the pore structure and the products on the pore wall of hardened foam concrete. Finally, the evolution mechanism of foams in new foam concrete w discussed.
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
危险品化学品经营许可证（带存储）