In this paper, a comprehensive semi-empirical model is developed to predict the drying shrinkage strain of concrete reinforced by graphene oxide nanosheets (GONs). The model involves various internal and external parameters. The effects of three factors,including the age when drying starts, the GON content and aspect ratio on the drying shrinkage strain of concrete reinforced with GONs are investigated. It is found that the presented results are in good agreement with the experimental data compared to the results obtained from the other models, including CABR, CEB-78, CEB-90, ACI209(92), B3, and GL2000 for plain concrete, and modified ACI209(92) and B3 models for concrete with GONs. Moreover, several sensitivity analyses are done for the drying shrinkage strain of concrete with 0.02, 0.05 and 0.08wt% as functions of the relative environmental humidity, temperature, compressive strength, cement content, aggregate-cement ratio, size and dimensions of the sample, gravel-sand ratio, sand-cement ratio, and water-cement ratio. It is noted that the developed model not only evaluates the drying shrinkage behavior of concrete containing GONs well but it can also be applied to predict the drying shrinkage strain of cement that is reinforced by GONs.
{"title":"Comprehensive modeling of drying shrinkage strain of graphene oxide nanosheet concrete","authors":"M. Mahmoodi, M. Khamehchi, M. Safi","doi":"10.1680/jadcr.21.00225","DOIUrl":"https://doi.org/10.1680/jadcr.21.00225","url":null,"abstract":"In this paper, a comprehensive semi-empirical model is developed to predict the drying shrinkage strain of concrete reinforced by graphene oxide nanosheets (GONs). The model involves various internal and external parameters. The effects of three factors,including the age when drying starts, the GON content and aspect ratio on the drying shrinkage strain of concrete reinforced with GONs are investigated. It is found that the presented results are in good agreement with the experimental data compared to the results obtained from the other models, including CABR, CEB-78, CEB-90, ACI209(92), B3, and GL2000 for plain concrete, and modified ACI209(92) and B3 models for concrete with GONs. Moreover, several sensitivity analyses are done for the drying shrinkage strain of concrete with 0.02, 0.05 and 0.08wt% as functions of the relative environmental humidity, temperature, compressive strength, cement content, aggregate-cement ratio, size and dimensions of the sample, gravel-sand ratio, sand-cement ratio, and water-cement ratio. It is noted that the developed model not only evaluates the drying shrinkage behavior of concrete containing GONs well but it can also be applied to predict the drying shrinkage strain of cement that is reinforced by GONs.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":"1 1","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41466270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Hasparyk, S. M. Torres, Francieli Tiecher, G. Amantino, Wesley Maciel de Souza
This experimental study aims to present the behavior of cement composites containing rice husk ash over time previously undergone high thermal curing. A specific initial thermal curing up to 85°C was designed to trigger delayed ettringite formation (DEF) as well as a specific exposure environment, by water immersion at 38°C, over one year. Expansion measurements and microstructural analyses were performed to evaluate the level of attack and the integrity of mortars and concretes. To complement the study, mechanical properties of concretes were assessed to detect the level of damages by delayed ettringite formation expansion. Mortar performed differently from concrete, bringing risks of mistaken conclusions about admixture performance. Anyway, concrete tests have indicated that rice husk ash was able just to reduce the level of expansions, nonetheless, the contents were not enough to mitigate completely the generated expansions and avoid delayed ettringite formation and, consequently, damage. Highlights • The potential of rice husk-ash to mitigate DEF was explored. • A comparison between the behavior of mortar and concrete mixtures was evaluated. • The expansions, mechanical properties and microstructure analyses were studied. • Mortar and concrete performed different. • The admixture of rice husk-ash did not play enough mitigative performance for DEF at content of 8% by cement weight.
{"title":"AFt/AFm distribution & microstructure-properties of rice husk ash concretes thermal-cured","authors":"N. Hasparyk, S. M. Torres, Francieli Tiecher, G. Amantino, Wesley Maciel de Souza","doi":"10.1680/jadcr.22.00116","DOIUrl":"https://doi.org/10.1680/jadcr.22.00116","url":null,"abstract":"This experimental study aims to present the behavior of cement composites containing rice husk ash over time previously undergone high thermal curing. A specific initial thermal curing up to 85°C was designed to trigger delayed ettringite formation (DEF) as well as a specific exposure environment, by water immersion at 38°C, over one year. Expansion measurements and microstructural analyses were performed to evaluate the level of attack and the integrity of mortars and concretes. To complement the study, mechanical properties of concretes were assessed to detect the level of damages by delayed ettringite formation expansion. Mortar performed differently from concrete, bringing risks of mistaken conclusions about admixture performance. Anyway, concrete tests have indicated that rice husk ash was able just to reduce the level of expansions, nonetheless, the contents were not enough to mitigate completely the generated expansions and avoid delayed ettringite formation and, consequently, damage. Highlights • The potential of rice husk-ash to mitigate DEF was explored. • A comparison between the behavior of mortar and concrete mixtures was evaluated. • The expansions, mechanical properties and microstructure analyses were studied. • Mortar and concrete performed different. • The admixture of rice husk-ash did not play enough mitigative performance for DEF at content of 8% by cement weight.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-04-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48249764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Formulating alkali-activated binders requires a clear understanding of the role of activator concentration and source material composition on product formation and strength gain. Alkaline-activation of a low-calcium fly ash binder with slag replacement at 30 and 50% by mass is evaluated. The reactivity of the binder and the compressive strength gain are evaluated using activating solutions of different NaOH molarities. Increasing the NaOH molarity produces a higher compressive strength in the activated binder. The primary reaction product formed in the activated binder is a calcium silicate hydrate with aluminium substitution (C-(A)-S-H). There is an increase in the C-(A)-S-H content, and a reduction in the porosity, with an increase in NaOH molarity. Slag contributes to early reactivity in the binder and the initial strength development while fly ash contributes to later age strength by silica enrichment of C-(A)-S-H. While increasing the NaOH molarity produces an increase in the early reactivity, the Na does not directly contribute to the reaction product formation. The Na from alkaline activator is not chemically bound to the C-(A)-S-H and can be removed by leaching in water. The increasing basicity with NaOH molarity enhances the contribution of low-calcium fly ash leading to higher silica enrichment of C-(A)-S-H.
{"title":"Production and evaluation of alkali-activated binders of low-calcium fly ash with slag replacement","authors":"K. C. Reddy, K. Subramaniam","doi":"10.1680/jadcr.22.00034","DOIUrl":"https://doi.org/10.1680/jadcr.22.00034","url":null,"abstract":"Formulating alkali-activated binders requires a clear understanding of the role of activator concentration and source material composition on product formation and strength gain. Alkaline-activation of a low-calcium fly ash binder with slag replacement at 30 and 50% by mass is evaluated. The reactivity of the binder and the compressive strength gain are evaluated using activating solutions of different NaOH molarities. Increasing the NaOH molarity produces a higher compressive strength in the activated binder. The primary reaction product formed in the activated binder is a calcium silicate hydrate with aluminium substitution (C-(A)-S-H). There is an increase in the C-(A)-S-H content, and a reduction in the porosity, with an increase in NaOH molarity. Slag contributes to early reactivity in the binder and the initial strength development while fly ash contributes to later age strength by silica enrichment of C-(A)-S-H. While increasing the NaOH molarity produces an increase in the early reactivity, the Na does not directly contribute to the reaction product formation. The Na from alkaline activator is not chemically bound to the C-(A)-S-H and can be removed by leaching in water. The increasing basicity with NaOH molarity enhances the contribution of low-calcium fly ash leading to higher silica enrichment of C-(A)-S-H.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44730702","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
To address the problems of poor thermal stability and over-retarding of cement slurry by retarders, as well as the sensitivity to the citric acid dosage and poor early strength of cement treated with hydroxycarboxylic acid retarders, citric acid intercalated hydrotalcite (Mg/Al-CA-LDH) with a sustained release effect was prepared by an anion exchange reaction between citric acid and magnesium aluminium layered double hydroxide (Mg/Al-CO3-LDH). The prepared citric acid-intercalated hydrotalcite exhibited good crystallinity and high thermal stability, where 39.92% citric acid could be inserted into the composite. Evaluation of the thickening and compressive strength of oil-well cement showed that Mg/Al-CA-LDH can effectively maintain the fluidity of cement slurry and improve its early compressive strength. Furthermore, because of the seed effect of hydrotalcite and the microrelease of citric acid in Mg/Al-CA-LDH, the synergistic effect of hydrotalcite and Mg/Al-CA-LDH can promote the setting of oil-well cement, where the effect is stable, and the thickening curve is stable, indicating right-angle thickening.
{"title":"Synthesis and characterization of a novel sustained-release-type citric acid intercalated hydrotalcite and its application in oil well cement","authors":"Tianpeng Zuo, Sheng Huang, Chunmei Zhang, Tao Gu, Kaiqiang Liu, Xiaowei Cheng","doi":"10.1680/jadcr.21.00059","DOIUrl":"https://doi.org/10.1680/jadcr.21.00059","url":null,"abstract":"To address the problems of poor thermal stability and over-retarding of cement slurry by retarders, as well as the sensitivity to the citric acid dosage and poor early strength of cement treated with hydroxycarboxylic acid retarders, citric acid intercalated hydrotalcite (Mg/Al-CA-LDH) with a sustained release effect was prepared by an anion exchange reaction between citric acid and magnesium aluminium layered double hydroxide (Mg/Al-CO3-LDH). The prepared citric acid-intercalated hydrotalcite exhibited good crystallinity and high thermal stability, where 39.92% citric acid could be inserted into the composite. Evaluation of the thickening and compressive strength of oil-well cement showed that Mg/Al-CA-LDH can effectively maintain the fluidity of cement slurry and improve its early compressive strength. Furthermore, because of the seed effect of hydrotalcite and the microrelease of citric acid in Mg/Al-CA-LDH, the synergistic effect of hydrotalcite and Mg/Al-CA-LDH can promote the setting of oil-well cement, where the effect is stable, and the thickening curve is stable, indicating right-angle thickening.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-02-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49512769","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mechanical properties and fracture mechanism of quasi-brittle material are considered largely relied on the mechanical properties of meso-components and the structure of how these components are combined together. In recent practice of numerical simulation, it has become a trend to consider the real structure of materials as accurately as possible. In this paper, macroscopic and mesoscopic bending behaviors of steel fiber reinforced reactive powder concrete (RPC) slabs with fiber volume content between 0.0% and 2.5% were investigated with both experimental tests and numerical simulations. Images obtained from X-ray CT were input into a program named RFPA3D-CT to build a modified 3D FEM model. The results indicate that the steel fibers can help to convert a brittle failure pattern of RPC into a ductile one. Compared with the specimen without fibers, the crack tortuosity and the bending strength of the specimens fiber content of 2.5% are increased by 20.25% and 308.80%, respectively. The bending performance of the numerical results obtained by the modified model are in good agreement with the experimental results, and the relative error values of the tortuosity and bending strength in the simulation compared with those in the experiment are all less than 15%. Moreover, AE parameters and AE curves obtained in RFPA3D-CT can be used to reveal the initiation and propagation process of cracks in RPC.
{"title":"Influence of steel fiber on bending behaviors of RPC based on X-ray CT and mesoscopic numerical simulation","authors":"Juan Lu, Yafang Zhang, Qingxuan Wang, Yongjie Huo","doi":"10.1680/jadcr.22.00005","DOIUrl":"https://doi.org/10.1680/jadcr.22.00005","url":null,"abstract":"Mechanical properties and fracture mechanism of quasi-brittle material are considered largely relied on the mechanical properties of meso-components and the structure of how these components are combined together. In recent practice of numerical simulation, it has become a trend to consider the real structure of materials as accurately as possible. In this paper, macroscopic and mesoscopic bending behaviors of steel fiber reinforced reactive powder concrete (RPC) slabs with fiber volume content between 0.0% and 2.5% were investigated with both experimental tests and numerical simulations. Images obtained from X-ray CT were input into a program named RFPA3D-CT to build a modified 3D FEM model. The results indicate that the steel fibers can help to convert a brittle failure pattern of RPC into a ductile one. Compared with the specimen without fibers, the crack tortuosity and the bending strength of the specimens fiber content of 2.5% are increased by 20.25% and 308.80%, respectively. The bending performance of the numerical results obtained by the modified model are in good agreement with the experimental results, and the relative error values of the tortuosity and bending strength in the simulation compared with those in the experiment are all less than 15%. Moreover, AE parameters and AE curves obtained in RFPA3D-CT can be used to reveal the initiation and propagation process of cracks in RPC.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47244648","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xun Xu, Yingjiang Li, Yongtao Sun, B. Yu, Hai-long Hu, Dan Li, Zong-Hai Hu, Shuang Wang, J. Meng, Bowen Yu
Basic magnesium sulfate cement was a kind of MgO-MgSO4-H2O modified ternary system cementitious material, which was prepared from light burned magnesia, magnesium sulfate heptahydrate, water and additives. In this paper, the effects of α-MgO/MgSO4, H2O/MgSO4, sand-to-binder ratio and superplasticizer dosage on the performance of basic magnesium sulfate cement mortar were studied for the first time. The results showed that for the 28-day flexural strength, the optimal α-MgO/MgSO4 was 10:1, H2O/MgSO4 was 16:1, sand-to-binder ratio was 0.8, and superplasticizer dosage was 0.3%. For the 28-day compressive strength, the optimal α-MgO/MgSO4 was 8:1, H2O/MgSO4 was 14:1, sand-to-binder ratio was 0.6, and superplasticizer dosage was 0.4%. For water resistance, the optimal α-MgO/MgSO4 was 12.5:1, H2O/MgSO4 was 14:1, sand-to-binder ratio was 0.2, and superplasticizer dosage was 0.1%. Based on the above experiment, the basic mix proportion range of basic magnesium sulfate cement mortar was α-MgO/MgSO4 of 8:1∼12.5:1, H2O/MgSO4 of 14:1∼16:1, sand-to-binder ratio of 0.2∼0.6 and superplasticizer dosage of 0.1∼0.4%.
{"title":"Investigation on performance of basic magnesium sulfate cement mortar","authors":"Xun Xu, Yingjiang Li, Yongtao Sun, B. Yu, Hai-long Hu, Dan Li, Zong-Hai Hu, Shuang Wang, J. Meng, Bowen Yu","doi":"10.1680/jadcr.22.00091","DOIUrl":"https://doi.org/10.1680/jadcr.22.00091","url":null,"abstract":"Basic magnesium sulfate cement was a kind of MgO-MgSO4-H2O modified ternary system cementitious material, which was prepared from light burned magnesia, magnesium sulfate heptahydrate, water and additives. In this paper, the effects of α-MgO/MgSO4, H2O/MgSO4, sand-to-binder ratio and superplasticizer dosage on the performance of basic magnesium sulfate cement mortar were studied for the first time. The results showed that for the 28-day flexural strength, the optimal α-MgO/MgSO4 was 10:1, H2O/MgSO4 was 16:1, sand-to-binder ratio was 0.8, and superplasticizer dosage was 0.3%. For the 28-day compressive strength, the optimal α-MgO/MgSO4 was 8:1, H2O/MgSO4 was 14:1, sand-to-binder ratio was 0.6, and superplasticizer dosage was 0.4%. For water resistance, the optimal α-MgO/MgSO4 was 12.5:1, H2O/MgSO4 was 14:1, sand-to-binder ratio was 0.2, and superplasticizer dosage was 0.1%. Based on the above experiment, the basic mix proportion range of basic magnesium sulfate cement mortar was α-MgO/MgSO4 of 8:1∼12.5:1, H2O/MgSO4 of 14:1∼16:1, sand-to-binder ratio of 0.2∼0.6 and superplasticizer dosage of 0.1∼0.4%.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-01-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44959556","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Polycarboxylate superplasticizer (PCE) is commonly sensitive to clay minerals, so this paper proposes synthesizing several clay-resistant superplasticizers (CR-PCE) using a novel self-made functional monomer. The resulting functional monomer and superplasticizers were characterized by Fourier transform infrared spectrophotometry (FT-IR) and gel permeation chromatography (GPC). The results show that the CR-PCE samples exhibit a better dispersion performance as compared to the conventional polycarboxylate superplasticizer (C-PCE) sample in the montmorillonite-bearing cement pastes. The adsorption amount of the CR-PCE samples on the Mmt was investigated by Ultraviolet-visible spectrophotometry (UV), and it was found that the CR-PCE samples have a lower clay sensitivity compared with the C-PCE sample. The X-ray diffraction (XRD) results of the montmorillonite (Mmt) reveal that the interlayer spacing of the Mmt treated by the CR-PCE samples was lower than that of the Mmt treated by the C-PCE sample. It can thus be concluded that the functional monomer can effectively improve the clay tolerance performance of PCE.
{"title":"Synthesis of polycarboxylate superplasticizer modified by self-made functional monomer for improving clay tolerance","authors":"Guangyang Wang, Yuanming Song","doi":"10.1680/jadcr.22.00118","DOIUrl":"https://doi.org/10.1680/jadcr.22.00118","url":null,"abstract":"Polycarboxylate superplasticizer (PCE) is commonly sensitive to clay minerals, so this paper proposes synthesizing several clay-resistant superplasticizers (CR-PCE) using a novel self-made functional monomer. The resulting functional monomer and superplasticizers were characterized by Fourier transform infrared spectrophotometry (FT-IR) and gel permeation chromatography (GPC). The results show that the CR-PCE samples exhibit a better dispersion performance as compared to the conventional polycarboxylate superplasticizer (C-PCE) sample in the montmorillonite-bearing cement pastes. The adsorption amount of the CR-PCE samples on the Mmt was investigated by Ultraviolet-visible spectrophotometry (UV), and it was found that the CR-PCE samples have a lower clay sensitivity compared with the C-PCE sample. The X-ray diffraction (XRD) results of the montmorillonite (Mmt) reveal that the interlayer spacing of the Mmt treated by the CR-PCE samples was lower than that of the Mmt treated by the C-PCE sample. It can thus be concluded that the functional monomer can effectively improve the clay tolerance performance of PCE.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45268381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Steel slag (SS) accounts for 15%∼20% of steelmaking output, its application in cement concrete was limited since the poor stability. In this study, the divalent metal oxide solid solution (RO phase) in SS was analog synthesized to study its hydration activity and expansibility. The results showed that the hydration activity and expansibility of MgO in analog-RO phase is affected by the content of FeO, with the increase of molar ratio (x) of FeO to MgO in analog-RO phase the autoclave expansion rate and hydration activity of the cement paste decreased. When x≤0.5, the RO phase had high hydration activity and could cause the poor soundness of SS. When x=1, the RO phase had low hydration activity and could cause the slight expansion of SS. When x≥2, the RO phase had no hydration activity and could not cause the expansion of SS. The control of different analog-RO phase composition induced different hydration and expansibility, which provided a theoretical basis for the influence of RO phase on the soundness of steel slag and putting forward measures to reduce the expansion of SS, promoting the high-volume utilization of SS in cement and concrete.
{"title":"Hydration activity and expansibility of different RO phase composition in steel slag","authors":"X. Zhao, Jiwei Hou, Zhimin Chen, Jiaxiang Liu","doi":"10.1680/jadcr.21.00227","DOIUrl":"https://doi.org/10.1680/jadcr.21.00227","url":null,"abstract":"Steel slag (SS) accounts for 15%∼20% of steelmaking output, its application in cement concrete was limited since the poor stability. In this study, the divalent metal oxide solid solution (RO phase) in SS was analog synthesized to study its hydration activity and expansibility. The results showed that the hydration activity and expansibility of MgO in analog-RO phase is affected by the content of FeO, with the increase of molar ratio (x) of FeO to MgO in analog-RO phase the autoclave expansion rate and hydration activity of the cement paste decreased. When x≤0.5, the RO phase had high hydration activity and could cause the poor soundness of SS. When x=1, the RO phase had low hydration activity and could cause the slight expansion of SS. When x≥2, the RO phase had no hydration activity and could not cause the expansion of SS. The control of different analog-RO phase composition induced different hydration and expansibility, which provided a theoretical basis for the influence of RO phase on the soundness of steel slag and putting forward measures to reduce the expansion of SS, promoting the high-volume utilization of SS in cement and concrete.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44190847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Air entrained wet shotcrete improves the pipeline transportation efficiency of concrete, besides, the characteristics of fine aggregate have different effects on the fluidity and mechanical properties of air entrained wet shotcrete. In this paper, mainly for air-entrained wet shotcrete, the effects of four different properties of fine aggregates on the fluidity and mechanical properties of air-entrained wet shotcrete were studied, especially the two factors of sand ratio and mud content. Fine aggregate properties include mud content (MC), sand ratio (SR), water content (WC) and particle size (PZ). The results showed that the fluidity and mechanical properties of wet shotcrete were the best when the sand ratio of fine aggregate is 0.56 and the water content is 3%; the fine aggregate has a reasonable particle size as far as possible; the montmorillonite contained in the mud inhibited the fluidity and mechanical properties, and the mud content should be kept as low as possible. The paper provides a reference for the practical application of air entraining wet shotcrete, so as to better deal with pipe blockage.
{"title":"Effect of fine aggregate on fluidity and mechanical strengths of wet shotcrete","authors":"Lianjun Chen, Jiahao Sun, Guoming Liu, Chunkui Li","doi":"10.1680/jadcr.22.00153","DOIUrl":"https://doi.org/10.1680/jadcr.22.00153","url":null,"abstract":"Air entrained wet shotcrete improves the pipeline transportation efficiency of concrete, besides, the characteristics of fine aggregate have different effects on the fluidity and mechanical properties of air entrained wet shotcrete. In this paper, mainly for air-entrained wet shotcrete, the effects of four different properties of fine aggregates on the fluidity and mechanical properties of air-entrained wet shotcrete were studied, especially the two factors of sand ratio and mud content. Fine aggregate properties include mud content (MC), sand ratio (SR), water content (WC) and particle size (PZ). The results showed that the fluidity and mechanical properties of wet shotcrete were the best when the sand ratio of fine aggregate is 0.56 and the water content is 3%; the fine aggregate has a reasonable particle size as far as possible; the montmorillonite contained in the mud inhibited the fluidity and mechanical properties, and the mud content should be kept as low as possible. The paper provides a reference for the practical application of air entraining wet shotcrete, so as to better deal with pipe blockage.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48737252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the work, an approach towards a carbon-neutral cement industry using CO2 mineralization of recycled concrete paste is investigated. It focuses on the effect of temperature on the enforced carbonation of cement paste. The enforced carbonation is a rapid process at ambient temperature, which is further accelerated at elevated temperatures. Moreover, the extend of the reaction is increased when the temperature rises. The carbonation reaction is divided into the following two kinetic stages: During the first stage, the carbonation kinetics is controlled by the availability of CO2 that increases at higher temperatures. During the second stage, the reaction kinetics is controlled by the dissolution of the hydrates. Increased temperature accelerates this process by increasing undersaturation level of the dissolving phases. The main carbonation products are calcium carbonate and an alumina-silica gel. The increasing temperature has limited impact on these phases, while the differences come mainly from the different degrees of carbonation.
{"title":"Effect of temperature on CO2 mineralization in recycled cement paste","authors":"M. Zając, M. Krol, F. Bullerjahn, J. Deja","doi":"10.1680/jadcr.22.00129","DOIUrl":"https://doi.org/10.1680/jadcr.22.00129","url":null,"abstract":"In the work, an approach towards a carbon-neutral cement industry using CO2 mineralization of recycled concrete paste is investigated. It focuses on the effect of temperature on the enforced carbonation of cement paste. The enforced carbonation is a rapid process at ambient temperature, which is further accelerated at elevated temperatures. Moreover, the extend of the reaction is increased when the temperature rises. The carbonation reaction is divided into the following two kinetic stages: During the first stage, the carbonation kinetics is controlled by the availability of CO2 that increases at higher temperatures. During the second stage, the reaction kinetics is controlled by the dissolution of the hydrates. Increased temperature accelerates this process by increasing undersaturation level of the dissolving phases. The main carbonation products are calcium carbonate and an alumina-silica gel. The increasing temperature has limited impact on these phases, while the differences come mainly from the different degrees of carbonation.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":" ","pages":""},"PeriodicalIF":2.0,"publicationDate":"2023-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48127678","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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