Pub Date : 2023-02-20DOI: 10.1080/21650373.2023.2178539
Xiaoniu Yu, Qiyong Zhang
Compared with the production of ordinary Portland cement (OPC) with large carbon emissions, biological carbon sequestration to prepare low-carbon cement can effectively decrease carbon dioxide (CO2) emissions, which can reduce the greenhouse effect, thereby reducing the frequency and intensity of climate disasters. Carbon-capturing bacteria (CCB) can capture atmospheric CO2 and convert it into bicarbonate ions, which can be combined with calcium ions to form CaCO3 cement that can partially replace OPC for dust control. This study compared the ability of two CCBs (Paenibacillus mucilaginosus and Streptomyces microflavus ) to capture CO2. The biomineralization efficiency of CaCO3 for P. mucilaginosus (39.34%) was much higher than that for S. microflavus (7.38%) in a Ca(NO3)2 solution in the concrete-curing room environment. The decomposition temperature of the CaCO3 crystals in DI was slightly higher than that of P. mucilaginosus and significantly higher than that of S. microflavus. When the spraying time was equal to three, 10% carbide sludge (CS) content was optimal according to the surface hardness (HD) of the consolidation layer of the sand samples. The CaCO3 mineralized by CCBs can be used to consolidate desert sand and dust in practical engineering applications.
{"title":"Microbially/CO2-derived CaCO3 cement and its microstructural and mechanical performance","authors":"Xiaoniu Yu, Qiyong Zhang","doi":"10.1080/21650373.2023.2178539","DOIUrl":"https://doi.org/10.1080/21650373.2023.2178539","url":null,"abstract":"Compared with the production of ordinary Portland cement (OPC) with large carbon emissions, biological carbon sequestration to prepare low-carbon cement can effectively decrease carbon dioxide (CO2) emissions, which can reduce the greenhouse effect, thereby reducing the frequency and intensity of climate disasters. Carbon-capturing bacteria (CCB) can capture atmospheric CO2 and convert it into bicarbonate ions, which can be combined with calcium ions to form CaCO3 cement that can partially replace OPC for dust control. This study compared the ability of two CCBs (Paenibacillus mucilaginosus and Streptomyces microflavus ) to capture CO2. The biomineralization efficiency of CaCO3 for P. mucilaginosus (39.34%) was much higher than that for S. microflavus (7.38%) in a Ca(NO3)2 solution in the concrete-curing room environment. The decomposition temperature of the CaCO3 crystals in DI was slightly higher than that of P. mucilaginosus and significantly higher than that of S. microflavus. When the spraying time was equal to three, 10% carbide sludge (CS) content was optimal according to the surface hardness (HD) of the consolidation layer of the sand samples. The CaCO3 mineralized by CCBs can be used to consolidate desert sand and dust in practical engineering applications.","PeriodicalId":48521,"journal":{"name":"Journal of Sustainable Cement-Based Materials","volume":"12 1","pages":"1156 - 1168"},"PeriodicalIF":4.4,"publicationDate":"2023-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45134806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-07DOI: 10.1080/21650373.2023.2169965
Yu Chen, Yu Zhang, Shanshan He, Minfei Liang, Yamei Zhang, E. Schlangen, O. Çopuroğlu
Limestone-calcined clay-cement (LC3), as one of the most promising sustainable cements, has been under development over the past decade. However, many uncertainties remain regarding its rheological behaviors, such as the metakaolin content of calcined clay. This study aims to investigate the effect of increasing the content of fine-grained metakaolin in calcined clay on the rheology of LC3 pastes. Rheological behaviors and early-age hydration of studied mixtures were characterized using flow curve, constant shear rate, small amplitude oscillatory shear and isothermal calorimetry tests. Results show that increasing the content of fine-grained metakaolin decreased flowability but promoted structural build-up and early-age hydration. These phenomena can be attributed to the decrease of mean interparticle distance caused by the increased amount of fine-grained metakaolin, which may enhance colloidal interactions, C-S-H nucleation and direct contact between particles. Overall, modifying the fine-grained metakaolin content is a feasible approach to control the rheology of LC3 pastes.
{"title":"Rheology control of limestone calcined clay cement pastes by modifying the content of fine-grained metakaolin","authors":"Yu Chen, Yu Zhang, Shanshan He, Minfei Liang, Yamei Zhang, E. Schlangen, O. Çopuroğlu","doi":"10.1080/21650373.2023.2169965","DOIUrl":"https://doi.org/10.1080/21650373.2023.2169965","url":null,"abstract":"Limestone-calcined clay-cement (LC3), as one of the most promising sustainable cements, has been under development over the past decade. However, many uncertainties remain regarding its rheological behaviors, such as the metakaolin content of calcined clay. This study aims to investigate the effect of increasing the content of fine-grained metakaolin in calcined clay on the rheology of LC3 pastes. Rheological behaviors and early-age hydration of studied mixtures were characterized using flow curve, constant shear rate, small amplitude oscillatory shear and isothermal calorimetry tests. Results show that increasing the content of fine-grained metakaolin decreased flowability but promoted structural build-up and early-age hydration. These phenomena can be attributed to the decrease of mean interparticle distance caused by the increased amount of fine-grained metakaolin, which may enhance colloidal interactions, C-S-H nucleation and direct contact between particles. Overall, modifying the fine-grained metakaolin content is a feasible approach to control the rheology of LC3 pastes.","PeriodicalId":48521,"journal":{"name":"Journal of Sustainable Cement-Based Materials","volume":"12 1","pages":"1126 - 1140"},"PeriodicalIF":4.4,"publicationDate":"2023-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49453683","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-02-06DOI: 10.1080/21650373.2023.2175272
Yi Wang, Zhangli Hu, Hua Li, Wen Xu, Jiaping Liu
Applying plastic expansive agent to solve the debonding and non-compacting problem in sealed structures (e.g. concrete-filled steel tube) caused by the deformation of concrete has become an important method. In this study, the effect of azodicarbonamide expansive agent (ADC) on the deformation, mechanical properties, hydration process, and pore structure of cement pastes and concrete was investigated. The results show that the low static yield stress and viscosity promote the formation and growth of bubbles, which are disadvantageous for their stabilization. The ADC reaction rate increases with the elevated temperature, which benefits for shortening the time to mitigate shrinkage. ADC has a limited effect on cement hydration but remarkably alters the pore structure. The balance between deformation and strength is considered to be the important criteria for determining the optimal dosage of ADC.
{"title":"Expansive deformation and mechanical properties of cementitious materials with azodicarbonamide expansive agent: influencing factors and mechanisms","authors":"Yi Wang, Zhangli Hu, Hua Li, Wen Xu, Jiaping Liu","doi":"10.1080/21650373.2023.2175272","DOIUrl":"https://doi.org/10.1080/21650373.2023.2175272","url":null,"abstract":"Applying plastic expansive agent to solve the debonding and non-compacting problem in sealed structures (e.g. concrete-filled steel tube) caused by the deformation of concrete has become an important method. In this study, the effect of azodicarbonamide expansive agent (ADC) on the deformation, mechanical properties, hydration process, and pore structure of cement pastes and concrete was investigated. The results show that the low static yield stress and viscosity promote the formation and growth of bubbles, which are disadvantageous for their stabilization. The ADC reaction rate increases with the elevated temperature, which benefits for shortening the time to mitigate shrinkage. ADC has a limited effect on cement hydration but remarkably alters the pore structure. The balance between deformation and strength is considered to be the important criteria for determining the optimal dosage of ADC.","PeriodicalId":48521,"journal":{"name":"Journal of Sustainable Cement-Based Materials","volume":"12 1","pages":"1141 - 1155"},"PeriodicalIF":4.4,"publicationDate":"2023-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45982497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-17DOI: 10.1080/21650373.2022.2163432
M. Zając, H. Hilbig, F. Bullerjahn, Mohsen Ben Haha
CO2 curing of fresh concrete is one of the solutions allowing direct carbon sequestration within the construction industry. Additionally, it enhances the early mechanical performance when comparing to traditional hydration curing. Temperature of carbonation curing has pronounced impact on both reactions involved in hardening of Portland cement: carbonation and hydration. Both reactions are accelerated with rising temperature, while the formed products and resulting microstructure are altered. Higher curing temperature promotes the precipitation of silica gel and C-S-H phase with reduced Ca/Si ratio. Furthermore, alumina and sulfate distributions among the reaction products are different. Temperature of carbonation curing has a distinct impact on the cement paste hydration after carbonation curing. The high curing temperature results in a densification of the matrix which limits further reaction progress, compared to the samples cured at lower temperatures. During the post hydration, calcium deficient system changes into C-S-H phase with higher Ca/Si and eventually portlandite.
{"title":"Reactions involved in carbonation hardening of Portland cement: effect of curing temperature","authors":"M. Zając, H. Hilbig, F. Bullerjahn, Mohsen Ben Haha","doi":"10.1080/21650373.2022.2163432","DOIUrl":"https://doi.org/10.1080/21650373.2022.2163432","url":null,"abstract":"CO2 curing of fresh concrete is one of the solutions allowing direct carbon sequestration within the construction industry. Additionally, it enhances the early mechanical performance when comparing to traditional hydration curing. Temperature of carbonation curing has pronounced impact on both reactions involved in hardening of Portland cement: carbonation and hydration. Both reactions are accelerated with rising temperature, while the formed products and resulting microstructure are altered. Higher curing temperature promotes the precipitation of silica gel and C-S-H phase with reduced Ca/Si ratio. Furthermore, alumina and sulfate distributions among the reaction products are different. Temperature of carbonation curing has a distinct impact on the cement paste hydration after carbonation curing. The high curing temperature results in a densification of the matrix which limits further reaction progress, compared to the samples cured at lower temperatures. During the post hydration, calcium deficient system changes into C-S-H phase with higher Ca/Si and eventually portlandite.","PeriodicalId":48521,"journal":{"name":"Journal of Sustainable Cement-Based Materials","volume":"12 1","pages":"1107 - 1125"},"PeriodicalIF":4.4,"publicationDate":"2023-01-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45847746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-02DOI: 10.1080/21650373.2022.2161661
Jiangtao Xu, Jiaqi Pei, D. Lu, Zhongzi Xu
For clarifying the effect of dolomite on the volume stability of Portland dolomite cement (PDC) at high reaction degree, the length change of PDC pastes with the replacement levels of 10–30 wt% dolomite and cured in different conditions was examined, in contrast with Portland limestone cement (PLC). The hydration products and microstructure were investigated using XRD, TGA, and SEM. Results indicate that at 40 and 60 °C the PDC and PLC show similar deformation patterns, with a small expansion. At 80 °C, however, the PDC are characterized by a higher expansion than the PLC, especially at high replacement levels. The reaction process of dolomite in PDC is dependent on the availability of aluminate phases. In the presence of free alumina, dolomite would react preferentially to form carboaluminates, hydrotalcite, and calcite. When the alumina is exhausted, dedolomitization reaction takes place producing brucite and calcite. The high expansion in PDC is mainly associated with the dedolomitization, which may result in the reinforcing frame volume and crystallization pressure due to the formation of brucite and calcite in confined space. However, the expansion of PDC is too small to cause damage to hardened pastes. Therefore, the incorporation of dolomite in PDC has no adverse effect on the volume stability of cement-based materials.
{"title":"Volume stability of Portland-dolomite cement pastes cured in different conditions","authors":"Jiangtao Xu, Jiaqi Pei, D. Lu, Zhongzi Xu","doi":"10.1080/21650373.2022.2161661","DOIUrl":"https://doi.org/10.1080/21650373.2022.2161661","url":null,"abstract":"For clarifying the effect of dolomite on the volume stability of Portland dolomite cement (PDC) at high reaction degree, the length change of PDC pastes with the replacement levels of 10–30 wt% dolomite and cured in different conditions was examined, in contrast with Portland limestone cement (PLC). The hydration products and microstructure were investigated using XRD, TGA, and SEM. Results indicate that at 40 and 60 °C the PDC and PLC show similar deformation patterns, with a small expansion. At 80 °C, however, the PDC are characterized by a higher expansion than the PLC, especially at high replacement levels. The reaction process of dolomite in PDC is dependent on the availability of aluminate phases. In the presence of free alumina, dolomite would react preferentially to form carboaluminates, hydrotalcite, and calcite. When the alumina is exhausted, dedolomitization reaction takes place producing brucite and calcite. The high expansion in PDC is mainly associated with the dedolomitization, which may result in the reinforcing frame volume and crystallization pressure due to the formation of brucite and calcite in confined space. However, the expansion of PDC is too small to cause damage to hardened pastes. Therefore, the incorporation of dolomite in PDC has no adverse effect on the volume stability of cement-based materials.","PeriodicalId":48521,"journal":{"name":"Journal of Sustainable Cement-Based Materials","volume":"12 1","pages":"1094 - 1106"},"PeriodicalIF":4.4,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45665112","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-28DOI: 10.1080/21650373.2022.2161660
N. Cristelo, J. Coelho, J. Rivera, I. García-Lodeiro, T. Miranda, A. Fernández-Jiménez
In steel manufacturing, electric arc furnaces are increasingly common, as they use mostly scrap metal as ore source. Thus, blast furnace slag (BFS) is decreasing, while electric arc slag (EAFS) is proportionally increasing. This study focuses on the potential of EAFS in alkaline cements, as precursor or aggregate. Different EAFS/BFS mixtures, some including fly ash (FA), were activated with a NaOH solution, and characterized from a mechanical and microstructural perspective. Selected pastes were used to prepare mortars, using EAFS as aggregate. Results showed that EAFS alone doesn’t deliver an adequate strength. However, when combined with BFS and FA, it formed compact matrices with significant mechanical strength and lower hydration heat. The use of EAFS as aggregate produced higher strength than obtained with silica sand. EAFS showed the potential to be applied as a precursor in alkaline cements, and the combination of BFS/EAFS yielded higher compressive strengths than obtained with BFS alone.
{"title":"Application of electric arc furnace slag as an alternative precursor to blast furnace slag in alkaline cements","authors":"N. Cristelo, J. Coelho, J. Rivera, I. García-Lodeiro, T. Miranda, A. Fernández-Jiménez","doi":"10.1080/21650373.2022.2161660","DOIUrl":"https://doi.org/10.1080/21650373.2022.2161660","url":null,"abstract":"In steel manufacturing, electric arc furnaces are increasingly common, as they use mostly scrap metal as ore source. Thus, blast furnace slag (BFS) is decreasing, while electric arc slag (EAFS) is proportionally increasing. This study focuses on the potential of EAFS in alkaline cements, as precursor or aggregate. Different EAFS/BFS mixtures, some including fly ash (FA), were activated with a NaOH solution, and characterized from a mechanical and microstructural perspective. Selected pastes were used to prepare mortars, using EAFS as aggregate. Results showed that EAFS alone doesn’t deliver an adequate strength. However, when combined with BFS and FA, it formed compact matrices with significant mechanical strength and lower hydration heat. The use of EAFS as aggregate produced higher strength than obtained with silica sand. EAFS showed the potential to be applied as a precursor in alkaline cements, and the combination of BFS/EAFS yielded higher compressive strengths than obtained with BFS alone.","PeriodicalId":48521,"journal":{"name":"Journal of Sustainable Cement-Based Materials","volume":"12 1","pages":"1081 - 1093"},"PeriodicalIF":4.4,"publicationDate":"2022-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47706916","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-27DOI: 10.1080/21650373.2022.2154287
Yue Wang, Jianhui Liu, Xiang Hu, Jun Chang, Tingting Zhang, Caijun Shi
Accelerated carbonation can promote the application of steel slag in construction materials. This method can not only resolve the fatal volume expansion of steel slag, but also sequestrate CO2. The carbonation thermodynamics, carbonation degree, carbonation methods and influencing factors of steel slag were reviewed. The theoretical CO2 uptake of steel slag is between 25% to 50%. However, the actual CO2 uptake distribution curve obeys normal distribution with a median value of 15%, which affected by carbonation methods, different influencing factors such as curing temperature, CO2 concentration and pressure, particle size of steel slag, liquid to solid ratio, and extraction agents. The improvement mechanism of accelerated carbonation on mechanical properties and stability of steel slag-based building materials was analyzed. Besides, different accelerated carbonated steel slag-based products with enhanced properties were summarized. Finally, some valuable suggestions concerning accelerated carbonation of steel slag were presented for further research and industrial application.
{"title":"Utilization of accelerated carbonation to enhance the application of steel slag: a review","authors":"Yue Wang, Jianhui Liu, Xiang Hu, Jun Chang, Tingting Zhang, Caijun Shi","doi":"10.1080/21650373.2022.2154287","DOIUrl":"https://doi.org/10.1080/21650373.2022.2154287","url":null,"abstract":"Accelerated carbonation can promote the application of steel slag in construction materials. This method can not only resolve the fatal volume expansion of steel slag, but also sequestrate CO2. The carbonation thermodynamics, carbonation degree, carbonation methods and influencing factors of steel slag were reviewed. The theoretical CO2 uptake of steel slag is between 25% to 50%. However, the actual CO2 uptake distribution curve obeys normal distribution with a median value of 15%, which affected by carbonation methods, different influencing factors such as curing temperature, CO2 concentration and pressure, particle size of steel slag, liquid to solid ratio, and extraction agents. The improvement mechanism of accelerated carbonation on mechanical properties and stability of steel slag-based building materials was analyzed. Besides, different accelerated carbonated steel slag-based products with enhanced properties were summarized. Finally, some valuable suggestions concerning accelerated carbonation of steel slag were presented for further research and industrial application.","PeriodicalId":48521,"journal":{"name":"Journal of Sustainable Cement-Based Materials","volume":"12 1","pages":"471 - 486"},"PeriodicalIF":4.4,"publicationDate":"2022-12-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46116249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-09DOI: 10.1080/21650373.2022.2152898
Cong Lu, Peiyun She, Han-Min Chu, Yiming Yao, C. Leung
REC-15 Polyvinyl alcohol (PVA) fibers are the most widely used fibers in engineered cementitious composites (ECC). To reduce the high cost of fibers and also to restrain the crack width, local PVA (C-PVA) fibers and Polyethylene terephthalate (PET) fibers are hybridized to replace the REC-15 PVA fibers. Single fiber pullout tests of C-PVA and PET fiber were carried out first. A series of mixes with varying combinations of PET/C-PVA fiber contents and FA/cement ratios were then tested and a digital image correlation system was used to observe the formation and development of cracks. More importantly, the tensile performance of the hybrid-fiber composites has shown comprehensive improvement. With the proper combination of C-PVA and PET fiber content, novel ECC composites with much lower fiber cost have been developed to achieve 4.85 MPa tensile strength, 5.11% strain capacity, and less than 0.08 mm average crack width.
{"title":"An investigation on the performance enhancement and cost reduction of engineered cementitious composites developed with local PVA and PET fibers","authors":"Cong Lu, Peiyun She, Han-Min Chu, Yiming Yao, C. Leung","doi":"10.1080/21650373.2022.2152898","DOIUrl":"https://doi.org/10.1080/21650373.2022.2152898","url":null,"abstract":"REC-15 Polyvinyl alcohol (PVA) fibers are the most widely used fibers in engineered cementitious composites (ECC). To reduce the high cost of fibers and also to restrain the crack width, local PVA (C-PVA) fibers and Polyethylene terephthalate (PET) fibers are hybridized to replace the REC-15 PVA fibers. Single fiber pullout tests of C-PVA and PET fiber were carried out first. A series of mixes with varying combinations of PET/C-PVA fiber contents and FA/cement ratios were then tested and a digital image correlation system was used to observe the formation and development of cracks. More importantly, the tensile performance of the hybrid-fiber composites has shown comprehensive improvement. With the proper combination of C-PVA and PET fiber content, novel ECC composites with much lower fiber cost have been developed to achieve 4.85 MPa tensile strength, 5.11% strain capacity, and less than 0.08 mm average crack width.","PeriodicalId":48521,"journal":{"name":"Journal of Sustainable Cement-Based Materials","volume":"12 1","pages":"1020 - 1032"},"PeriodicalIF":4.4,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45267400","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Power ultrasound (PUS) was first used to assist the mixing of cement paste. Five ultrasonic power levels (0 W, 240 W, 480 W, 720 W, and 912 W) were adopted. The compressive strength was tested. The hydration process and products of the cement paste were analyzed by inductively coupled plasma–optical emission spectrometry (ICP–OES), isothermal calorimetry, thermogravimetric analysis (TGA), quantitative X-ray diffraction (QXRD), mercury intrusion porosimetry (MIP), backscattered electron–energy dispersive spectroscopy (BSE–EDS), and environmental scanning electron microscopy (ESEM). The results indicated that the compressive strength was improved by using the PUS-assisted mixing. Moreover, PUS-assisted mixing significantly promoted the formation of calcium hydroxide (CH) and ettringite. The crystallization and densification process of the C-S-H phase was accelerated. The macroscopic voids and large capillary pores were substantially reduced. Therefore, PUS-assisted mixing is a promising technology for improving hydration behaviors and strength of cement paste, which could be used in fabricated production.
{"title":"Effect of power ultrasound-assisted mixing on the hydration and microstructural development of cement paste","authors":"Guangqi Xiong, Chong Wang, Shuai Zhou, Ying Zhao, Yunxuan Li, Yang Liu, Jian Qiu","doi":"10.1080/21650373.2022.2153390","DOIUrl":"https://doi.org/10.1080/21650373.2022.2153390","url":null,"abstract":"Power ultrasound (PUS) was first used to assist the mixing of cement paste. Five ultrasonic power levels (0 W, 240 W, 480 W, 720 W, and 912 W) were adopted. The compressive strength was tested. The hydration process and products of the cement paste were analyzed by inductively coupled plasma–optical emission spectrometry (ICP–OES), isothermal calorimetry, thermogravimetric analysis (TGA), quantitative X-ray diffraction (QXRD), mercury intrusion porosimetry (MIP), backscattered electron–energy dispersive spectroscopy (BSE–EDS), and environmental scanning electron microscopy (ESEM). The results indicated that the compressive strength was improved by using the PUS-assisted mixing. Moreover, PUS-assisted mixing significantly promoted the formation of calcium hydroxide (CH) and ettringite. The crystallization and densification process of the C-S-H phase was accelerated. The macroscopic voids and large capillary pores were substantially reduced. Therefore, PUS-assisted mixing is a promising technology for improving hydration behaviors and strength of cement paste, which could be used in fabricated production.","PeriodicalId":48521,"journal":{"name":"Journal of Sustainable Cement-Based Materials","volume":"12 1","pages":"1061 - 1072"},"PeriodicalIF":4.4,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41989837","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-08DOI: 10.1080/21650373.2022.2153455
Shizhe Wang, Jing Wu, Zhixian Wang, Song You, Haiping Wu, Luoxin Wang
Rational storage and efficient utilization of rainwater resources are effective means to solve the problems of urban waterlogging and clean water shortage. Many new photothermal conversion devices have been developed for seawater desalination, but the photothermal conversion function has rarely been applied to building materials for water purification. In this study, porous cement-based photothermal conversion materials (PCPCM) were prepared by coating a layer of photothermal conversion materials on the surface of porous cement products, and their photothermal conversion efficiency and water evaporation efficiency were investigated. The results show that PCPCM with graphene as photothermal conversion layer has the highest photothermal conversion efficiency and water evaporation rate of 76.08% and 1.162 kg m−2 h−1, respectively, under one sunlight intensity (1.0 KW m−2). This work presents a key step towards efficient, low-cost and sustainable purification of rainwater into clean water with renewable solar energy, providing new ideas for functional sponge city design.
雨水资源的合理储存和高效利用是解决城市内涝和清水短缺问题的有效手段。已经开发了许多用于海水淡化的新型光热转换装置，但光热转换功能很少应用于用于水净化的建筑材料。本研究通过在多孔水泥制品表面涂覆一层光热转换材料制备了多孔水泥基光热转换材料，并对其光热转换效率和水蒸发效率进行了研究。结果表明，以石墨烯为光热转换层的PCPCM具有最高的光热转换效率，水蒸发率分别为76.08%和1.162 kg m−2 h−1，在一个阳光强度（1.0 KW m−2）。这项工作为利用可再生太阳能高效、低成本和可持续地将雨水净化为清洁水迈出了关键一步，为功能性海绵城市设计提供了新思路。
{"title":"Research on water evaporation efficiency of porous cement-based photothermal conversion materials","authors":"Shizhe Wang, Jing Wu, Zhixian Wang, Song You, Haiping Wu, Luoxin Wang","doi":"10.1080/21650373.2022.2153455","DOIUrl":"https://doi.org/10.1080/21650373.2022.2153455","url":null,"abstract":"Rational storage and efficient utilization of rainwater resources are effective means to solve the problems of urban waterlogging and clean water shortage. Many new photothermal conversion devices have been developed for seawater desalination, but the photothermal conversion function has rarely been applied to building materials for water purification. In this study, porous cement-based photothermal conversion materials (PCPCM) were prepared by coating a layer of photothermal conversion materials on the surface of porous cement products, and their photothermal conversion efficiency and water evaporation efficiency were investigated. The results show that PCPCM with graphene as photothermal conversion layer has the highest photothermal conversion efficiency and water evaporation rate of 76.08% and 1.162 kg m−2 h−1, respectively, under one sunlight intensity (1.0 KW m−2). This work presents a key step towards efficient, low-cost and sustainable purification of rainwater into clean water with renewable solar energy, providing new ideas for functional sponge city design.","PeriodicalId":48521,"journal":{"name":"Journal of Sustainable Cement-Based Materials","volume":"12 1","pages":"1073 - 1080"},"PeriodicalIF":4.4,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48845606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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