Pub Date : 2025-01-14DOI: 10.1016/j.cemconcomp.2025.105933
Jie Yu , Fengming Xu , Hanghua Zhang , Junhong Ye , Jiangtao Yu , Jian-Guo Dai , Yiwei Weng
This study investigates the use of incinerator bottom ash (IBA) as a supplementary cementitious material to mitigate early age shrinkage in 3D printed engineered cementitious composites (3DP-ECC). IBA was processed through milling and thermal treatment before incorporation into 3DP-ECC. The fresh and hardened properties, hydration kinetics and products, early age shrinkage, and microstructural characteristics of 3DP-ECC with IBA were evaluated. Results indicate that pre-treated IBA reduces autogenous shrinkage and plastic shrinkage by 56 % and 30 %, respectively. The substitution of IBA increases the volume fraction of macropores (>1000 nm) of 3DP-ECC at 3 days and 7 days by approximately 300 % and 500 %, respectively, alleviating early age shrinkage. Sustainability analysis reveals that the incorporation of IBA can reduce the normalized embodied energy and carbon footprint of 3DP-ECC by over 17 %. These findings provide a promising approach to utilizing waste materials in mitigating early age shrinkage in 3DP-ECC towards sustainable digital construction.
本研究调查了焚化炉底灰(IBA)作为补充胶凝材料的使用情况,以减轻三维打印工程胶凝复合材料(3DP-ECC)的早期龄期收缩。在将焚烧炉底灰加入 3DP-ECC 之前,先对其进行研磨和热处理。评估了含有 IBA 的 3DP-ECC 的新鲜和硬化性能、水化动力学和产物、早期龄期收缩以及微观结构特征。结果表明,预处理 IBA 可使自生收缩率和塑性收缩率分别降低 56% 和 30%。取代 IBA 后,3DP-ECC 在 3 天和 7 天时的大孔体积分数(1000 nm)分别增加了约 300 % 和 500 %,从而缓解了早期龄期收缩。可持续性分析表明,加入 IBA 可使 3DP-ECC 的归一化内含能源和碳足迹减少 17% 以上。这些研究结果为利用废弃材料缓解 3DP-ECC 早期收缩提供了一种可行的方法,从而实现可持续的数字建筑。
{"title":"Leveraging incinerator bottom ash for mitigating early age shrinkage in 3D printed engineered cementitious composites","authors":"Jie Yu , Fengming Xu , Hanghua Zhang , Junhong Ye , Jiangtao Yu , Jian-Guo Dai , Yiwei Weng","doi":"10.1016/j.cemconcomp.2025.105933","DOIUrl":"10.1016/j.cemconcomp.2025.105933","url":null,"abstract":"<div><div>This study investigates the use of incinerator bottom ash (IBA) as a supplementary cementitious material to mitigate early age shrinkage in 3D printed engineered cementitious composites (3DP-ECC). IBA was processed through milling and thermal treatment before incorporation into 3DP-ECC. The fresh and hardened properties, hydration kinetics and products, early age shrinkage, and microstructural characteristics of 3DP-ECC with IBA were evaluated. Results indicate that pre-treated IBA reduces autogenous shrinkage and plastic shrinkage by 56 % and 30 %, respectively. The substitution of IBA increases the volume fraction of macropores (>1000 nm) of 3DP-ECC at 3 days and 7 days by approximately 300 % and 500 %, respectively, alleviating early age shrinkage. Sustainability analysis reveals that the incorporation of IBA can reduce the normalized embodied energy and carbon footprint of 3DP-ECC by over 17 %. These findings provide a promising approach to utilizing waste materials in mitigating early age shrinkage in 3DP-ECC towards sustainable digital construction.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105933"},"PeriodicalIF":10.8,"publicationDate":"2025-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-11DOI: 10.1016/j.cemconcomp.2025.105934
H. Majdoubi , Y. Haddaji , M. Nadi , H. Hamdane , S. Mansouri , R. Boulif , Y. Samih , M. Oumam , B. Manoun , J. Alami , Y. Tamraoui , H. Hannache
This study investigates the utilization of hexafluorosilicic acid (AFS), a by-product of the phosphate industry with negative environmental impacts, as a catalyst in the synthesis of acid-based geopolymers at room temperature. Specifically, the research focuses on the acceleration of the acid geopolymerization reaction to produce phosphoric acid-based geopolymers and examines the influence of varying AFS concentrations on the geopolymerization process, microstructural properties, and mechanical strength. The experimental approach includes quasi-isothermal DSC analysis, temperature monitoring of geopolymer paste over time, vicat automatic tests, compressive strength, FTIR, DRX, SEM, and EDX. Results indicate that geopolymers prepared without AFS remained unconsolidated even after three days at room temperature. In contrast, adding AFS reduced the setting time to as little as 18 min with 7 % AFS by weight of the paste, demonstrating a significant reduction in setting time from several days to few minutes. Isothermal DSC and internal temperature monitoring of the geopolymer paste during setting revealed that minimal AFS additions (1%–5%) effectively accelerate the geopolymerization kinetics by catalyzing the highly exothermic second step, thus enhancing the subsequent steps of geopolymerization. However, precise control of AFS concentration is crucial, as insufficient amounts do not fully catalyze the reaction, while excessive AFS causes a rapid temperature rise (up to 108 °C in less than 10 min), hindering the initial dissolution step and leading to incomplete aluminosilicate source dissolution. Compressive strength tests showed that adding 5 % AFS at room temperature increased strength by 87 % compared to samples without AFS, which required 60 °C for 14 MPa. However, strength decreased with AFS concentrations above 5 %. After 28 days, a 25 % increase in strength was observed compared to 7-day samples, highlighting that most strength development occurs within the first 7 days, while microstructural analyses confirmed that AFS serves as a catalyst without altering the crystal phase or the geopolymer network. This study underscores the potential of AFS to significantly enhance the performance of acid-based geopolymers, providing a sustainable approach to utilizing an industrial by-product while improving material properties.
{"title":"Sustainable geopolymer synthesis catalyzed by hexafluorosilicic acid: A low-energy approach using phosphate industrial waste","authors":"H. Majdoubi , Y. Haddaji , M. Nadi , H. Hamdane , S. Mansouri , R. Boulif , Y. Samih , M. Oumam , B. Manoun , J. Alami , Y. Tamraoui , H. Hannache","doi":"10.1016/j.cemconcomp.2025.105934","DOIUrl":"10.1016/j.cemconcomp.2025.105934","url":null,"abstract":"<div><div>This study investigates the utilization of hexafluorosilicic acid (AFS), a by-product of the phosphate industry with negative environmental impacts, as a catalyst in the synthesis of acid-based geopolymers at room temperature. Specifically, the research focuses on the acceleration of the acid geopolymerization reaction to produce phosphoric acid-based geopolymers and examines the influence of varying AFS concentrations on the geopolymerization process, microstructural properties, and mechanical strength. The experimental approach includes quasi-isothermal DSC analysis, temperature monitoring of geopolymer paste over time, vicat automatic tests, compressive strength, FTIR, DRX, SEM, and EDX. Results indicate that geopolymers prepared without AFS remained unconsolidated even after three days at room temperature. In contrast, adding AFS reduced the setting time to as little as 18 min with 7 % AFS by weight of the paste, demonstrating a significant reduction in setting time from several days to few minutes. Isothermal DSC and internal temperature monitoring of the geopolymer paste during setting revealed that minimal AFS additions (1%–5%) effectively accelerate the geopolymerization kinetics by catalyzing the highly exothermic second step, thus enhancing the subsequent steps of geopolymerization. However, precise control of AFS concentration is crucial, as insufficient amounts do not fully catalyze the reaction, while excessive AFS causes a rapid temperature rise (up to 108 °C in less than 10 min), hindering the initial dissolution step and leading to incomplete aluminosilicate source dissolution. Compressive strength tests showed that adding 5 % AFS at room temperature increased strength by 87 % compared to samples without AFS, which required 60 °C for 14 MPa. However, strength decreased with AFS concentrations above 5 %. After 28 days, a 25 % increase in strength was observed compared to 7-day samples, highlighting that most strength development occurs within the first 7 days, while microstructural analyses confirmed that AFS serves as a catalyst without altering the crystal phase or the geopolymer network. This study underscores the potential of AFS to significantly enhance the performance of acid-based geopolymers, providing a sustainable approach to utilizing an industrial by-product while improving material properties.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105934"},"PeriodicalIF":10.8,"publicationDate":"2025-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142961374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-10DOI: 10.1016/j.cemconcomp.2025.105935
Hanxiong Lyu, Shipeng Zhang, Chi Sun Poon
A water-insoluble mineral, chlorellestadite (CE, Ca10(SiO4)3(SO4)3Cl2), would be formed in the preheater coatings of cement kilns when using chlorine-containing plastics as alternative fuels. This work investigated the viability of employing CE as an SCM to enhance the utilization of chlorine-containing fuels in cement-making. Substituting 20 wt% CE in dry-cast pastes (CE20), which were prepared by compaction method with zero workability, exhibited decreased compressive strength after 1d carbonation curing because of reduced cement content. However, carbonating CE introduced secondary gypsum into the binder system, leading to more ettringite formed in pores after water curing, aligning with thermodynamic modeling predictions. Its formation refined the pore structure, leading to 28d strength of CE20 (93.4 MPa) exceeding the OPC reference by 21.1 %. These findings underscored the potential of using CE as an SCM in dry-cast non-structural concrete and the advantages of carbonating minerals to generate secondary gypsum and ettringite for enhancing concrete properties.
{"title":"Developing high-strength dry-cast pastes by incorporating carbonatable chlorellestadite","authors":"Hanxiong Lyu, Shipeng Zhang, Chi Sun Poon","doi":"10.1016/j.cemconcomp.2025.105935","DOIUrl":"10.1016/j.cemconcomp.2025.105935","url":null,"abstract":"<div><div>A water-insoluble mineral, chlorellestadite (CE, Ca<sub>10</sub>(SiO<sub>4</sub>)<sub>3</sub>(SO<sub>4</sub>)<sub>3</sub>Cl<sub>2</sub>), would be formed in the preheater coatings of cement kilns when using chlorine-containing plastics as alternative fuels. This work investigated the viability of employing CE as an SCM to enhance the utilization of chlorine-containing fuels in cement-making. Substituting 20 wt% CE in dry-cast pastes (CE20), which were prepared by compaction method with zero workability, exhibited decreased compressive strength after 1d carbonation curing because of reduced cement content. However, carbonating CE introduced secondary gypsum into the binder system, leading to more ettringite formed in pores after water curing, aligning with thermodynamic modeling predictions. Its formation refined the pore structure, leading to 28d strength of CE20 (93.4 MPa) exceeding the OPC reference by 21.1 %. These findings underscored the potential of using CE as an SCM in dry-cast non-structural concrete and the advantages of carbonating minerals to generate secondary gypsum and ettringite for enhancing concrete properties.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105935"},"PeriodicalIF":10.8,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939580","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-10DOI: 10.1016/j.cemconcomp.2025.105928
Han Gao , Iman Munadhil Abbas Al-Damad , Ayesha Siddika , Taehwan Kim , Stephen Foster , Ailar Hajimohammadi
Alkali activated materials (AAMs), are gaining traction as sustainable alternatives to traditional Portland cement. However, their practical application is often limited by rapid setting times and poor workability. Although sodium carbonate and silica fume have been applied in synthesising AAMs, their effects on the reaction kinetics and structural development of one-part AAMs remain unknown. This research addresses this knowledge gap by investigating the impact of partially replacing sodium metasilicate with a blend of sodium carbonate and densified silica fume. Our study reveals that this substitution extends the setting time of one-part AAMs by eight times while maintaining comparable compressive strength after three days of curing. Detailed analyses using in-situ FTIR, activator dissolution, and isothermal calorimetry show that delayed dissolution of silica fume and carbonate ions significantly slows early-age reactions. This delayed reaction enhances the workability retention of one-part AAMs. Moreover, the modified AAM develops a more robust C-(N)-A-S-H gel structure, characterised by longer chain lengths and higher crosslinking. These findings provide a practical solution for improving the workability and structural integrity of one-part AAMs, paving the way for the development of advanced one-part AAMs with commercial viability and superior performance.
碱活化材料(AAMs)作为传统硅酸盐水泥的可持续替代品正受到越来越多的关注。然而,它们的实际应用往往受到凝结时间短和可加工性差的限制。虽然碳酸钠和硅灰已被用于合成AAMs,但它们对单组分AAMs的反应动力学和结构发展的影响尚不清楚。本研究通过研究用碳酸钠和致密硅粉的混合物部分取代偏硅酸钠的影响,解决了这一知识差距。我们的研究表明,这种替代将单组分AAMs的凝结时间延长了8倍,同时在养护3天后保持相当的抗压强度。使用原位红外光谱、活化剂溶解和等温量热法进行的详细分析表明,硅灰和碳酸盐离子的延迟溶解显著减缓了早期反应。这种延迟反应增强了单组分aam的可加工性保留。此外,改性AAM形成了更坚固的C-(N) a - s - h凝胶结构,具有更长的链长和更高的交联性。这些发现为提高单片式aam的可加工性和结构完整性提供了切实可行的解决方案,为开发具有商业可行性和优越性能的先进单片式aam铺平了道路。
{"title":"Enhancing the workability retention of one-part alkali activated binders by adjusting the chemistry of the activators","authors":"Han Gao , Iman Munadhil Abbas Al-Damad , Ayesha Siddika , Taehwan Kim , Stephen Foster , Ailar Hajimohammadi","doi":"10.1016/j.cemconcomp.2025.105928","DOIUrl":"10.1016/j.cemconcomp.2025.105928","url":null,"abstract":"<div><div>Alkali activated materials (AAMs), are gaining traction as sustainable alternatives to traditional Portland cement. However, their practical application is often limited by rapid setting times and poor workability. Although sodium carbonate and silica fume have been applied in synthesising AAMs, their effects on the reaction kinetics and structural development of one-part AAMs remain unknown. This research addresses this knowledge gap by investigating the impact of partially replacing sodium metasilicate with a blend of sodium carbonate and densified silica fume. Our study reveals that this substitution extends the setting time of one-part AAMs by eight times while maintaining comparable compressive strength after three days of curing. Detailed analyses using in-situ FTIR, activator dissolution, and isothermal calorimetry show that delayed dissolution of silica fume and carbonate ions significantly slows early-age reactions. This delayed reaction enhances the workability retention of one-part AAMs. Moreover, the modified AAM develops a more robust C-(N)-A-S-H gel structure, characterised by longer chain lengths and higher crosslinking. These findings provide a practical solution for improving the workability and structural integrity of one-part AAMs, paving the way for the development of advanced one-part AAMs with commercial viability and superior performance.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105928"},"PeriodicalIF":10.8,"publicationDate":"2025-01-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142961373","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article presents the investigation findings on the combined effect of seawater and carbonation curing on two types of binders – blended binder containing blast furnace slag (BFS) and laboratory synthesized pure β-C2S. Samples were prepared using freshwater and seawater as mixing water. After casting, the samples were exposed to accelerated CO2 curing for 7 days and then exposed to seawater for up to 90 days. The results revealed that the use of seawater as mixing water has substantially different effects on the performances of β-C2S compared to blended cement. Specifically, the use of seawater as the mixing water resulted in a threefold increase in the amount of carbonates formation in β-C2S paste compared to the samples prepared by mixing with fresh water. The seawater mixed and CO2 cured β-C2S paste samples showed continuous increase in strength even after extended exposure to seawater and reached around 75 MPa strength, which is nearly 100 % increase compared to the samples prepared with freshwater mixing. For β-C2S samples, the presence of Mg ions along with slightly higher pH resulted in the formation of vaterite and Mg-calcite contributing to superior performances. Additionally, after exposure to seawater, the silica gel phase captured Mg from seawater to form M-S-H. However, such drastic benefits of using seawater were not observed in the case of blended binders. The presence of Al in blended cement led to the formation of layered double hydroxides, including hydrotalcite and hydrocalumite, which limited the benefits of using seawater. Additionally, the presence of Al also resulted in the formation of ettringite when exposed to seawater. Because of these effects, a slight reduction in strength was observed in case of carbonation cured blended cement after their exposure to seawater.
{"title":"New insights into the interaction between seawater and CO2-activated calcium silicate composites","authors":"Farzana Mustari Nishat, Ishrat Baki Borno, Adhora Tahsin, Warda Ashraf","doi":"10.1016/j.cemconcomp.2025.105929","DOIUrl":"10.1016/j.cemconcomp.2025.105929","url":null,"abstract":"<div><div>This article presents the investigation findings on the combined effect of seawater and carbonation curing on two types of binders – blended binder containing blast furnace slag (BFS) and laboratory synthesized pure β-C<sub>2</sub>S. Samples were prepared using freshwater and seawater as mixing water. After casting, the samples were exposed to accelerated CO<sub>2</sub> curing for 7 days and then exposed to seawater for up to 90 days. The results revealed that the use of seawater as mixing water has substantially different effects on the performances of β-C<sub>2</sub>S compared to blended cement. Specifically, the use of seawater as the mixing water resulted in a threefold increase in the amount of carbonates formation in β-C<sub>2</sub>S paste compared to the samples prepared by mixing with fresh water. The seawater mixed and CO<sub>2</sub> cured β-C<sub>2</sub>S paste samples showed continuous increase in strength even after extended exposure to seawater and reached around 75 MPa strength, which is nearly 100 % increase compared to the samples prepared with freshwater mixing. For β-C<sub>2</sub>S samples, the presence of Mg ions along with slightly higher pH resulted in the formation of vaterite and Mg-calcite contributing to superior performances. Additionally, after exposure to seawater, the silica gel phase captured Mg from seawater to form M-S-H. However, such drastic benefits of using seawater were not observed in the case of blended binders. The presence of Al in blended cement led to the formation of layered double hydroxides, including hydrotalcite and hydrocalumite, which limited the benefits of using seawater. Additionally, the presence of Al also resulted in the formation of ettringite when exposed to seawater. Because of these effects, a slight reduction in strength was observed in case of carbonation cured blended cement after their exposure to seawater.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105929"},"PeriodicalIF":10.8,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937323","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-09DOI: 10.1016/j.cemconcomp.2025.105932
Matthieu Mesnage , Rachelle Omnée , Johan Colin , Hamidreza Ramezani , Jena Jeong , Encarnacion Raymundo-Piñero
Carbonation is a natural process in concrete where atmospheric CO2 diffuses into the pores of the material and reacts with cement hydrates to form calcium carbonate. Although this process can help to sequester atmospheric CO2 and mitigate rising levels in urban areas, it slows down over time, resulting in low CO2 uptake over the service life of concrete. This study proposes a sustainable method to improve carbonation kinetics and CO2 capture in cement materials by incorporating highly porous biochar. The biochar, derived from seaweed pyrolysis, has a highly developed surface area, including micropores optimised for CO2 adsorption, mesopores and macropores, as well as oxygen-rich surface groups. These properties allow the biochar to efficiently adsorb CO2 and retain water. The biochar particles embedded in the cement matrix act as reservoirs for water and CO2, influencing hydration and carbonation. The addition of biochar increases water retention in the composite, which promotes the formation of capillary pores and enhances the carbonation process. Experimental data and numerical simulations show that the adsorption of CO₂ in the micropores of biochar facilitates the flow of CO2 through the composite, allowing deeper carbonation. The interaction between biochar and cement matrix enhances CO2 diffusion and promotes calcium carbonate formation both within the biochar and at the biochar-cement interface, further improving CO2 uptake. The study demonstrates that the incorporation of porous biochar into cement materials significantly increases their potential for CO2 capture, offering a promising approach to sustainable construction and carbon sequestration.
{"title":"Porous biochar for improving the CO2 uptake capacities and kinetics of concrete","authors":"Matthieu Mesnage , Rachelle Omnée , Johan Colin , Hamidreza Ramezani , Jena Jeong , Encarnacion Raymundo-Piñero","doi":"10.1016/j.cemconcomp.2025.105932","DOIUrl":"10.1016/j.cemconcomp.2025.105932","url":null,"abstract":"<div><div>Carbonation is a natural process in concrete where atmospheric CO<sub>2</sub> diffuses into the pores of the material and reacts with cement hydrates to form calcium carbonate. Although this process can help to sequester atmospheric CO<sub>2</sub> and mitigate rising levels in urban areas, it slows down over time, resulting in low CO<sub>2</sub> uptake over the service life of concrete. This study proposes a sustainable method to improve carbonation kinetics and CO<sub>2</sub> capture in cement materials by incorporating highly porous biochar. The biochar, derived from seaweed pyrolysis, has a highly developed surface area, including micropores optimised for CO<sub>2</sub> adsorption, mesopores and macropores, as well as oxygen-rich surface groups. These properties allow the biochar to efficiently adsorb CO<sub>2</sub> and retain water. The biochar particles embedded in the cement matrix act as reservoirs for water and CO<sub>2</sub>, influencing hydration and carbonation. The addition of biochar increases water retention in the composite, which promotes the formation of capillary pores and enhances the carbonation process. Experimental data and numerical simulations show that the adsorption of CO₂ in the micropores of biochar facilitates the flow of CO<sub>2</sub> through the composite, allowing deeper carbonation. The interaction between biochar and cement matrix enhances CO<sub>2</sub> diffusion and promotes calcium carbonate formation both within the biochar and at the biochar-cement interface, further improving CO<sub>2</sub> uptake. The study demonstrates that the incorporation of porous biochar into cement materials significantly increases their potential for CO<sub>2</sub> capture, offering a promising approach to sustainable construction and carbon sequestration.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105932"},"PeriodicalIF":10.8,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937249","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-01-09DOI: 10.1016/j.cemconcomp.2025.105926
Qifeng Lyu , Yalun Wang , Dongjian Chen , Shiyuan Liu , Justin Mbabazi , Pinghua Zhu , Jiquan Lu , Shaowei Wang , Fengxiang Yin
To increase the manufacturing efficiency of rechargeable concrete which can alleviate the problem that intermittent new energy is difficult to integrate into the power grid, a new type of concrete structural supercapacitor (CSSC) was proposed here by using mortar-extrusion 3D printing with the carbon-black-coated Ni foam being the electrodes and reinforcement. The printability, energy storage properties, mechanical strengths, and microstructures of the printed CSSC were investigated and analyzed. Results showed adding electrodes increased the buildability because the Ni foam provided more supportiveness for the mortar. However, too many electrodes, especially for thicker ones, would damage the buildability, because thicker electrodes hindered mortar extrusion. The energy storage properties, i.e., the maximum areal capacitance and ionic conductivity of the printed CSSC are 1.59 mF/cm2 and 7.2 mS/cm, respectively, which can be increased by using more conductive electrolytes. Furthermore, adding carbon black to the electrodes or increasing the thickness of the electrodes enhanced the areal capacitance and ionic conductivity, because these methods increased the contact area of electrons and ions. The maximum compressive strength and flexural strength of the printed CSSC are 32.5 MPa and 12.9 MPa, respectively, which benefited from better printability and reinforcement. However, more thicker electrodes would over-reinforce the concrete. Moreover, the carbon black reduced the bonding between the printing mortar and Ni foam, resulting in decreased mechanical strength of the printed CSSC. This study provides an efficient method to manufacture the CSSC, and insights into the properties of the printed CSSC, which may facilitate future CSSC applications.
{"title":"Energy storage properties and mechanical strengths of 3D printed porous concrete structural supercapacitors reinforced by electrodes made of carbon-black-coated Ni foam","authors":"Qifeng Lyu , Yalun Wang , Dongjian Chen , Shiyuan Liu , Justin Mbabazi , Pinghua Zhu , Jiquan Lu , Shaowei Wang , Fengxiang Yin","doi":"10.1016/j.cemconcomp.2025.105926","DOIUrl":"10.1016/j.cemconcomp.2025.105926","url":null,"abstract":"<div><div>To increase the manufacturing efficiency of rechargeable concrete which can alleviate the problem that intermittent new energy is difficult to integrate into the power grid, a new type of concrete structural supercapacitor (CSSC) was proposed here by using mortar-extrusion 3D printing with the carbon-black-coated Ni foam being the electrodes and reinforcement. The printability, energy storage properties, mechanical strengths, and microstructures of the printed CSSC were investigated and analyzed. Results showed adding electrodes increased the buildability because the Ni foam provided more supportiveness for the mortar. However, too many electrodes, especially for thicker ones, would damage the buildability, because thicker electrodes hindered mortar extrusion. The energy storage properties, i.e., the maximum areal capacitance and ionic conductivity of the printed CSSC are 1.59 mF/cm<sup>2</sup> and 7.2 mS/cm, respectively, which can be increased by using more conductive electrolytes. Furthermore, adding carbon black to the electrodes or increasing the thickness of the electrodes enhanced the areal capacitance and ionic conductivity, because these methods increased the contact area of electrons and ions. The maximum compressive strength and flexural strength of the printed CSSC are 32.5 MPa and 12.9 MPa, respectively, which benefited from better printability and reinforcement. However, more thicker electrodes would over-reinforce the concrete. Moreover, the carbon black reduced the bonding between the printing mortar and Ni foam, resulting in decreased mechanical strength of the printed CSSC. This study provides an efficient method to manufacture the CSSC, and insights into the properties of the printed CSSC, which may facilitate future CSSC applications.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105926"},"PeriodicalIF":10.8,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142939625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-09DOI: 10.1016/j.cemconcomp.2025.105930
Maciej Szeląg, Patryk Rumiński, Rafał Panek
This study examines the effects of highly reactive, mesoporous MCM-41 silica on the thermal resistance and microstructural stability of Portland cement paste (CP). The motivation is to enhance cement composites (CC) properties using supplementary cementitious materials (SCMs), addressing environmental challenges from global cement production. The research involved modifying CP with 0–2 wt% MCM-41 and subjecting it to thermal loads from 20 °C to 700 °C. Evaluations included compressive and tensile strengths, density, water absorption, and shrinkage. Characterization techniques like X-ray diffraction (XRD) and mercury intrusion porosimetry (MIP) analysed phase composition and pore distribution. Results showed that MCM-41 significantly improved compressive strength, with a 26.9 % increase at 0.75 wt% content. Tensile strength also improved up to 33.8 % for 0.25–1 wt% MCM-41 content. Thermal stability tests indicated enhanced performance in the 200–500 °C range by reducing microcrack formation. XRD analysis revealed that MCM-41 influenced the phase composition, particularly delaying the thermal decomposition of portlandite and enhancing the stability of calcium silicate hydrates (CSH). Microstructural analysis revealed a denser, more cohesive cement matrix with reduced water absorption and shrinkage, enhancing durability. Additionally, MIP studies showed that MCM-41 contributed to a finer pore structure, improving the overall mechanical properties despite increased porosity. To supplement the findings, peak models have been tested to assess the ability to numerically predict pore size distribution of thermally loaded CP. Thus, MCM-41 is effective for improving the thermal and mechanical properties of CP, offering potential for applications in thermally stressed environments, contributing to more sustainable construction materials.
{"title":"Microstructure transformation of MCM-41 modified cement paste subjected to thermal load and modelling of its pore size distribution","authors":"Maciej Szeląg, Patryk Rumiński, Rafał Panek","doi":"10.1016/j.cemconcomp.2025.105930","DOIUrl":"10.1016/j.cemconcomp.2025.105930","url":null,"abstract":"<div><div>This study examines the effects of highly reactive, mesoporous MCM-41 silica on the thermal resistance and microstructural stability of Portland cement paste (CP). The motivation is to enhance cement composites (CC) properties using supplementary cementitious materials (SCMs), addressing environmental challenges from global cement production. The research involved modifying CP with 0–2 wt% MCM-41 and subjecting it to thermal loads from 20 °C to 700 °C. Evaluations included compressive and tensile strengths, density, water absorption, and shrinkage. Characterization techniques like X-ray diffraction (XRD) and mercury intrusion porosimetry (MIP) analysed phase composition and pore distribution. Results showed that MCM-41 significantly improved compressive strength, with a 26.9 % increase at 0.75 wt% content. Tensile strength also improved up to 33.8 % for 0.25–1 wt% MCM-41 content. Thermal stability tests indicated enhanced performance in the 200–500 °C range by reducing microcrack formation. XRD analysis revealed that MCM-41 influenced the phase composition, particularly delaying the thermal decomposition of portlandite and enhancing the stability of calcium silicate hydrates (CSH). Microstructural analysis revealed a denser, more cohesive cement matrix with reduced water absorption and shrinkage, enhancing durability. Additionally, MIP studies showed that MCM-41 contributed to a finer pore structure, improving the overall mechanical properties despite increased porosity. To supplement the findings, peak models have been tested to assess the ability to numerically predict pore size distribution of thermally loaded CP. Thus, MCM-41 is effective for improving the thermal and mechanical properties of CP, offering potential for applications in thermally stressed environments, contributing to more sustainable construction materials.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105930"},"PeriodicalIF":10.8,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937251","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-01-09DOI: 10.1016/j.cemconcomp.2025.105924
Jionghuang He, Yingliang Zhao, Yong Tao, Peiliang Shen, Chi Sun Poon
Pretreatment-induced initial hydration would significantly influence subsequent carbonation. However, the evolution of microstructure and performance resulting from the synergistic action of hydration and carbonation remains systematically unexplored. This study investigates carbonation kinetics, microstructure and micro/macro mechanical properties of carbonated cement pastes (CCPs) under the synergistic action of initial hydration and subsequent carbonation, while elucidating the underlying mechanisms. The results revealed that unhydrated cement exhibited a peak carbonation rate of 0.65 W/g, increasing by approximately 83 % when the cement underwent an 8 h of initial curing, demonstrating the enhancement in the carbonation reactivity due to initial hydration. However, the carbonation efficiency of CCPs increased initially and then decreased as initial hydration extended. This trend emerged because initial hydration enhanced carbonation reactivity, whereas excessive hydration concurrently obstructed CO2 transport. Furthermore, optimal initial hydration was essential for the synergistic interaction between hydration and carbonation, resulting in reduced porosity and a more homogeneous microstructure, as well as improved mechanical properties. These findings underscore the need to carefully consider the synergistic action of initial hydration and subsequent carbonation when designing pretreatment protocols.
{"title":"Insights into the synergistic action of initial hydration and subsequent carbonation of Portland cement","authors":"Jionghuang He, Yingliang Zhao, Yong Tao, Peiliang Shen, Chi Sun Poon","doi":"10.1016/j.cemconcomp.2025.105924","DOIUrl":"10.1016/j.cemconcomp.2025.105924","url":null,"abstract":"<div><div>Pretreatment-induced initial hydration would significantly influence subsequent carbonation. However, the evolution of microstructure and performance resulting from the synergistic action of hydration and carbonation remains systematically unexplored. This study investigates carbonation kinetics, microstructure and micro/macro mechanical properties of carbonated cement pastes (CCPs) under the synergistic action of initial hydration and subsequent carbonation, while elucidating the underlying mechanisms. The results revealed that unhydrated cement exhibited a peak carbonation rate of 0.65 W/g, increasing by approximately 83 % when the cement underwent an 8 h of initial curing, demonstrating the enhancement in the carbonation reactivity due to initial hydration. However, the carbonation efficiency of CCPs increased initially and then decreased as initial hydration extended. This trend emerged because initial hydration enhanced carbonation reactivity, whereas excessive hydration concurrently obstructed CO<sub>2</sub> transport. Furthermore, optimal initial hydration was essential for the synergistic interaction between hydration and carbonation, resulting in reduced porosity and a more homogeneous microstructure, as well as improved mechanical properties. These findings underscore the need to carefully consider the synergistic action of initial hydration and subsequent carbonation when designing pretreatment protocols.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105924"},"PeriodicalIF":10.8,"publicationDate":"2025-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937245","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
By virtue of its superior strength, high toughness, and low porosity, ultra-high-performance concrete (UHPC) has a wide range of application prospects in construction engineering. However, the interfacial transition zone (ITZ) formed between the cementitious matrix and steel fiber seriously restricts the steel fiber's strength utilization rate in UHPC. Hence, in this work, graphene oxide (GO) is employed to be coated on the steel fiber surface to strengthen the UHPC. The results demonstrate that through a three-step GO coating approach, the roughness and hydrophilicity of the steel fiber surface can be enhanced by about 280.6 % and 40.6 % compared with plain steel fiber. The coated GO can provide pore-infilling and nucleation effects during the hydration processes of the UHPC, thus decreasing the porosity by 37.5 % compared with non-GO reinforcement. After the three-step coating treatment, the compressive and bending strength of the coated-GO reinforced UHPC is enhanced by 33.7 % and 26.2 %, respectively. The molecular dynamic simulation results further reveal that benefiting from the crack-bridging effects of the coated GO, the interface between the steel fiber surface and cement matrix is prone to a ductile failure, with the failure energy of the C-S-H composites increasing by about 320%–1340 %. The findings advanced by this work can enhance the understanding of nano-cement technology and promote the potential application of the GO-coated fiber to generate high-performance UHPC.
{"title":"Mechanical performance enhancement of UHPC via ITZ improvement using graphene oxide-coated steel fibers","authors":"Yuan Gao , Zhangjianing Cheng , Jiajian Yu , Xiaonong Guo , Yanming Liu , Weiqiang Chen","doi":"10.1016/j.cemconcomp.2025.105931","DOIUrl":"10.1016/j.cemconcomp.2025.105931","url":null,"abstract":"<div><div>By virtue of its superior strength, high toughness, and low porosity, ultra-high-performance concrete (UHPC) has a wide range of application prospects in construction engineering. However, the interfacial transition zone (ITZ) formed between the cementitious matrix and steel fiber seriously restricts the steel fiber's strength utilization rate in UHPC. Hence, in this work, graphene oxide (GO) is employed to be coated on the steel fiber surface to strengthen the UHPC. The results demonstrate that through a three-step GO coating approach, the roughness and hydrophilicity of the steel fiber surface can be enhanced by about 280.6 % and 40.6 % compared with plain steel fiber. The coated GO can provide pore-infilling and nucleation effects during the hydration processes of the UHPC, thus decreasing the porosity by 37.5 % compared with non-GO reinforcement. After the three-step coating treatment, the compressive and bending strength of the coated-GO reinforced UHPC is enhanced by 33.7 % and 26.2 %, respectively. The molecular dynamic simulation results further reveal that benefiting from the crack-bridging effects of the coated GO, the interface between the steel fiber surface and cement matrix is prone to a ductile failure, with the failure energy of the C-S-H composites increasing by about 320%–1340 %. The findings advanced by this work can enhance the understanding of nano-cement technology and promote the potential application of the GO-coated fiber to generate high-performance UHPC.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105931"},"PeriodicalIF":10.8,"publicationDate":"2025-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142937250","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}