Cement & concrete composites最新文献_第8页

Enhancement mechanism of wet-carbonated recycled concrete aggregates subjected to calcium-rich and magnesium-rich industrial reclaimed wastewater sources

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-02-12 DOI: 10.1016/j.cemconcomp.2025.105983

Ning Li, Cise Unluer

{"title":"Enhancement mechanism of wet-carbonated recycled concrete aggregates subjected to calcium-rich and magnesium-rich industrial reclaimed wastewater sources","authors":"Ning Li, Cise Unluer","doi":"10.1016/j.cemconcomp.2025.105983","DOIUrl":"10.1016/j.cemconcomp.2025.105983","url":null,"abstract":"<div><div>While efficient in enhancing recycled concrete aggregates' (RCAs) performance, wet carbonation demands significant amounts of water. Addressing this, we investigated carbonation of RCAs in tap-water (TW), concrete batching plant wash-water (WW), and reject brine (RB). Composition and microstructure of carbonated RCAs and their impact on reaction and mechanical properties of recycled aggregate concrete (RAC) were examined. Although the dissolution of Ca-containing components in RCAs was slower in WW, the high Ca(OH)<sub>2</sub> content in WW enhanced carbonation, leading to the formation of large calcite particles (1–2 μm). Despite a 56 % increase in RAC strength compared to the control, WW-RAC revealed slightly lower strengths than TW-RAC, which contained finer calcite particles (0.1–0.3 μm). The presence of Mg<sup>2+</sup> in RB accelerated the dissolution of Ca components in RCAs due to the lower solubility product constant of Mg(OH)<sub>2</sub> compared to Ca(OH)<sub>2</sub>, thereby promoting early-stage carbonation. As carbonation progressed, Mg<sup>2+</sup> was recovered from the carbonation product into the solution, with a recovery rate of 94 %. This Mg-modification resulted in the formation of 0.1–0.3 μm calcite particles along with needle-shaped Mg-calcite, enhancing bond strength. Results demonstrated feasibility of using reclaimed industrial wastewater in enhancing CO<sub>2</sub> sequestration, while significantly improving RCAs’ properties.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"158 ","pages":"Article 105983"},"PeriodicalIF":10.8,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143393706","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}

引用次数: 0

Hydration and physicochemical immobilization mechanisms of pozzolanic-hazardous waste in supersulfated cement

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-02-10 DOI: 10.1016/j.cemconcomp.2025.105970

Jiaxing Ban , Jian-Xin Lu , Bin Ma , Ligang Peng , Hongjian Du , Dingqiang Fan , Jun Yao , Baoshan Xing , Chi Sun Poon

{"title":"Hydration and physicochemical immobilization mechanisms of pozzolanic-hazardous waste in supersulfated cement","authors":"Jiaxing Ban , Jian-Xin Lu , Bin Ma , Ligang Peng , Hongjian Du , Dingqiang Fan , Jun Yao , Baoshan Xing , Chi Sun Poon","doi":"10.1016/j.cemconcomp.2025.105970","DOIUrl":"10.1016/j.cemconcomp.2025.105970","url":null,"abstract":"<div><div>Ordinary Portland cement (OPC) is a versatile cement binder suitable for solidifying hazardous wastes, while its production induces significant carbon emissions. This study developed a novel low-carbon supersulphated phosphogypsum slag cement (SPSC) with the inclusion of pozzolanic-hazardous waste and investigated the synergetic mechanism of its pozzolanic reaction and immobilization behavior. The hydration characteristics of SPSC were explored using ionic chromatography, XRD, and hydration heat tests. The study also assessed the effectiveness of SPSC in immobilizing hazardous waste using toxicity characteristic leaching procedure and sequential extraction procedure tests, and explored these mechanisms through XRD, SEM, Zeta potential, NMR, and progressive leaching tests. The results indicate that the SPSC system is more effective in immobilizing hazardous waste than OPC. This superior performance is attributed to the lower Ca/Si ratio and higher Al/Si ratio in SPSC, which results in the formation of hydrates with more negative charges than OPC and thus stronger physical adsorption of heavy metals. Additionally, the longer gel chains with larger interlayer zones in SPSC contribute to better solidification of heavy metals. Larger amounts of ettringite in SPSC also aids the immobilization by facilitating the exchange of Al ions for heavy metals. The excess SO<sub>4</sub><sup>2−</sup> in the pore solution of SPSC binder could help immobilize heavy metals by sulfate precipitation. Overall, this study provides new insights into the sustainable immobilization of hazardous waste by adopting SPSC.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"158 ","pages":"Article 105970"},"PeriodicalIF":10.8,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143375505","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}

引用次数: 0

Optimization and performance regulation of pipe piles based on nano-calcium silicate hydrated (n-C-S-H)

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-02-07 DOI: 10.1016/j.cemconcomp.2025.105977

Xiaofeng Han , Penggang Wang , Zijun Ling , Rihong Zhang , Zhenxing Du , Mengzhuo Sun , Xiaomeng Sui , Dongxuan Wei

{"title":"Optimization and performance regulation of pipe piles based on nano-calcium silicate hydrated (n-C-S-H)","authors":"Xiaofeng Han , Penggang Wang , Zijun Ling , Rihong Zhang , Zhenxing Du , Mengzhuo Sun , Xiaomeng Sui , Dongxuan Wei","doi":"10.1016/j.cemconcomp.2025.105977","DOIUrl":"10.1016/j.cemconcomp.2025.105977","url":null,"abstract":"<div><div>Prestressed high-strength concrete (PHC) pipe piles are widely used in various construction projects. However, higher steam curing temperatures and times in the preparation of pipe piles severely affect material performance, while increasing cost and environmental pollution. <em>This study investigates the use of nanoscale calcium-silicate-hydrate (n-C-S-H) to reduce curing temperature and time, ensuring high demoulding strength and short demoulding time of pipe piles.</em> Samples with n-C-S-H content of 0 %, 1 %, 2 % and 4 % were examined under curing times of 6 and 8 h and temperatures of 60 °C and 80 °C. The results show that it is feasible to solve the problem of reduced strength of samples due to reduced temperature by adding n-C-S-H, and increasing the n-C-S-H content while decreasing the steam curing times is favourable to the compressive strength of the samples. Through lowering the curing temperature, time and n-C-S-H addition both optimize the pore structure of the samples and the delayed ettringite formation (DEF) can be prevented, also contributes greatly to the improvement of sample durability. The results provide valuable insights into the preparation of cementitious materials for pipe piles and contribute to the development of more durable and sustainable infrastructure materials.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"158 ","pages":"Article 105977"},"PeriodicalIF":10.8,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143258465","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}

引用次数: 0

Digital-volume-correlation-assisted crack extraction using X-ray computed tomography images of cementitious materials

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-02-07 DOI: 10.1016/j.cemconcomp.2025.105968

Shuxian Hong , Zhongbo Yuan , Disheng Pan , Chuan Kuang , Biqin Dong , Shengxin Fan

引用次数: 0

New insights into the retardation mechanism of phosphorus slag on the early cement hydration

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-02-07 DOI: 10.1016/j.cemconcomp.2025.105963

Shiyu Zhuang , Qiang Wang , Yichen Shan , Ruiquan Jia , Zihan Zhou

引用次数: 0

Development of 3D-printable alkali-activated GGBFS and fly ash binder-based mortars with concrete demolition waste as aggregates

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-02-06 DOI: 10.1016/j.cemconcomp.2025.105954

M. Gurunandan , Aparna Sai Surya Sree Nedunuri , Jayant Tanwar , Prakash Nanthagopalan , Salman Muhammad

{"title":"Development of 3D-printable alkali-activated GGBFS and fly ash binder-based mortars with concrete demolition waste as aggregates","authors":"M. Gurunandan , Aparna Sai Surya Sree Nedunuri , Jayant Tanwar , Prakash Nanthagopalan , Salman Muhammad","doi":"10.1016/j.cemconcomp.2025.105954","DOIUrl":"10.1016/j.cemconcomp.2025.105954","url":null,"abstract":"<div><div>3D-printable alkali-activated mortar mixtures using concrete demolition waste (CDW) as aggregates, which are pumpable, extrudable, buildable up to 1000 mm with an open time of 180 minutes were developed in this study. The mixtures provided a minimum compressive strength of 50 MPa at 28 days age. The effect of various parameters such as binder composition, water-to-binder ratio, molar modulus and activator dosage on workability of the mixtures was investigated. The mixtures were assessed for pumpability, extrudability and buildability in fresh state and for compressive and splitting tensile strength in hardened state. The high workability mixtures (spread diameter>180 mm) recorded lower pumping pressure (<6 bar) and higher extrusion test discharge (>25 cm<sup>3</sup>/s at 25 rpm) inferring that they were easier to pump and extrude. However, they possessed lower strength (<1 kg) and stiffness (<2 kg/mm) at 20<sup>th</sup> minute in empirical buildability test, leading to lower buildable height (100 mm). The mixtures with spread diameter of 135–165 mm having static yield stress of 1.8–2.4 kPa, were apt for 3D-printing as it was buildable (>500 mm) without compromising on pumpability and extrudability. FTIR, XRD and TGA studies revealed that the prolonged workable time was due to the formation of sodium carbonate resulting from the reaction of carbonate phases in CDW with sodium hydroxide. The printing process has not affected the mechanical properties of the mixtures and there is no cold joint formed between subsequently printed layers. The 3D-printed specimens exhibited an anisotropic index of less than 0.30 indicating that they were isotopic in compression.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"157 ","pages":"Article 105954"},"PeriodicalIF":10.8,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143257818","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}

引用次数: 0

Tensile behavior simulation of ECC/SHCC at subzero temperatures based on a fiber/interface combination constitutive model

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-02-06 DOI: 10.1016/j.cemconcomp.2025.105969

Yanlin Huo , Xiaoyu Han , Chunran Wu , Dong Lu , Huayang Sun , Zhitao Chen , Yingzi Yang , Victor C. Li

{"title":"Tensile behavior simulation of ECC/SHCC at subzero temperatures based on a fiber/interface combination constitutive model","authors":"Yanlin Huo , Xiaoyu Han , Chunran Wu , Dong Lu , Huayang Sun , Zhitao Chen , Yingzi Yang , Victor C. Li","doi":"10.1016/j.cemconcomp.2025.105969","DOIUrl":"10.1016/j.cemconcomp.2025.105969","url":null,"abstract":"<div><div>The performance degradation of Engineered Cementitious Composites/Strain-hardening cementitious composites (ECC/SHCC) at subzero temperatures is becoming a widespread concern. However, experimental testing and data acquisition in cold environments are very difficult and demanding. It is an inevitable trend to use numerical simulation for research. In this paper, a finite element model based on a fiber/interface combination constitutive model was proposed to simulate the tensile behavior of SHCC at subzero temperatures. While the validity of the model was verified using 16 groups of tests, the reduction in multiple cracking and the increased proportion of fiber and interface failures induced with decreasing temperature were explored. The effect of matrix cracking strength on the tensile properties of SHCC was further compared. It was found that a lower matrix cracking strength could help SHCC to maintain high ductility at −60 °C, and the tensile strain capacity could reach 6.58 %. Therefore, it is crucial to control the matrix cracking strength in the design and application of SHCC in cold regions. The simulation method in this paper is expected to provide new insights for the development of high ductility SHCC in winter climate.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"158 ","pages":"Article 105969"},"PeriodicalIF":10.8,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143192358","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}

引用次数: 0

X-ray computed tomography-based characterisation of graphene nanoplatelets re-agglomeration in hardened cement composites

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-02-05 DOI: 10.1016/j.cemconcomp.2025.105967

Zhaohua Wang , Meini Su , Yong Wang , Cise Unluer , Suning Li

{"title":"X-ray computed tomography-based characterisation of graphene nanoplatelets re-agglomeration in hardened cement composites","authors":"Zhaohua Wang , Meini Su , Yong Wang , Cise Unluer , Suning Li","doi":"10.1016/j.cemconcomp.2025.105967","DOIUrl":"10.1016/j.cemconcomp.2025.105967","url":null,"abstract":"<div><div>Graphene Nanoplatelets (GNPs) have been found to be an effective additive for enhancing the mechanical strength of cementitious materials, attributed to the role they play as nucleation sites. However, there is not a direct correlation on the enhancing effect of graphene with increasing graphene dosage, resulting in different optimal dosages for different binders and mix designs. This study aims to develop a method to clarify the governing factor that determines the optimal graphene dosage in mortar mixes. X-ray computed tomography (XCT) was used to identify the size, surface area and distribution/re-agglomeration of graphene nanoplatelets in the prepared mixes. Compressive strength tests and TGA analysis were carried out to evaluate correlations among the total surface area of graphene nanoplatelets, mechanical performance, and cement hydration. Out of the three graphene dosages (0.035, 0.07, and 0.1 wt% by mass of cement) used in this study, samples with 0.07 wt% graphene revealed the highest total surface area of graphene nanoplatelets, hydration degree, and compressive strength. Results revealed that the enhancing effect of graphene addition in cement-based mixes was associated with the total surface area of the graphene nanoplatelets. A larger surface area contributed to stronger mechanical reinforcement by providing an increased number of nucleation sites in the pore solution.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"158 ","pages":"Article 105967"},"PeriodicalIF":10.8,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143192359","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}

引用次数: 0

Innovative ZIF-8 modified ER@EC microcapsules: Enhancing slow-release and longevity for superior self-healing in cementitious materials

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-02-04 DOI: 10.1016/j.cemconcomp.2025.105966

Shiyu Zhang , Zijian Song , Haoliang Zhang , Zilang Huang , Hui Rong , Linhua Jiang , Yunsheng Zhang

{"title":"Innovative ZIF-8 modified ER@EC microcapsules: Enhancing slow-release and longevity for superior self-healing in cementitious materials","authors":"Shiyu Zhang , Zijian Song , Haoliang Zhang , Zilang Huang , Hui Rong , Linhua Jiang , Yunsheng Zhang","doi":"10.1016/j.cemconcomp.2025.105966","DOIUrl":"10.1016/j.cemconcomp.2025.105966","url":null,"abstract":"<div><div>Using microcapsules (MCs) for self-healing is one of the most cutting-edge strategies for repairing concrete cracks and improving the durability of reinforced concrete (RC) structures. MCs with ethyl cellulose (EC) as the shell material possess non-toxicity, high stability, and satisfactory encapsulation capacity. However, EC-based MCs suffer from the premature release of core materials due to their porous nature. This study synthesized the zeolitic imidazolate framework-8 (ZIF-8) and embedded it into the EC shell to enable a long-acting healing function of epoxy resin (ER) @ EC MCs. The morphology, thermal stability, chemical structure, release rates, and particle size of the ER@EC/ZIF-8 MCs were evaluated. The first and secondary self-healing performances of mortars with different MC dosages were determined. The results demonstrated the successful embedding of ZIF-8 into the MCs, with a 20 % dosage of ZIF-8 modification achieving the most sustained release. Furthermore, ER@EC/ZIF-8 MCs effectively reduced pores larger than 77.45 nm and decreased the overall porosity by 3.13 %. ZIF-8 modification enhanced strength healing, particularly the long-acting aspect, with the secondary healing rate peaking at 31.48 % at a 3 % dosage of modified MCs under dual 30 % <em>f</em><sub>c0</sub> pre-damage. Meanwhile, the highest first healing rate (22.02 %) was also observed at a dosage of 3 % modified MCs under 30 % <em>f</em><sub>c0</sub> pre-damage. Generally, the modified MCs showed a superior healing effect than the unmodified MCs. As a newly developed self-healing MC, the ER@EC/ZIF-8 MCs are expected to confer multifunctional properties to RC structures.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"158 ","pages":"Article 105966"},"PeriodicalIF":10.8,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083146","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}

引用次数: 0

A novel electromigration-based microbial self-healing strategy for existing concrete structures

IF 10.8 1区工程技术

Cement & concrete composites Pub Date : 2025-02-04 DOI: 10.1016/j.cemconcomp.2025.105965

Zhenxiao Bi , Jing Xu , Hao Sun , Qing Chen , Hehua Zhu

{"title":"A novel electromigration-based microbial self-healing strategy for existing concrete structures","authors":"Zhenxiao Bi , Jing Xu , Hao Sun , Qing Chen , Hehua Zhu","doi":"10.1016/j.cemconcomp.2025.105965","DOIUrl":"10.1016/j.cemconcomp.2025.105965","url":null,"abstract":"<div><div>The prevailing self-healing of concrete cracks based on microbial-induced carbonate precipitation (MICP) has been limited to new structures since healing agents have to be pre-embedded during fresh mixing stage. In this study, a novel microbial self-healing strategy based on electromigration of bacterial spores is proposed for existing concrete. To this end, the feasibility of this new method is first verified, and the self-healing performances of the microbial mortar based on electromigration of spores are assessed. Results reveal that the applied electric field improves the physiological activity of spores but not affects the mineralogy and morphology of biomineralized products. Although a prolonged electrical treatment time or an enhanced electric field intensity results in a loss of physiological activity, the number of spores migrated into the mortar increases. The viability of spores is well preserved upon electromigration, and most of the spores are identified in the subsurface layer of the mortar with a thickness over 200 μm. With an electric field intensity of 1 V/cm and treatment time longer than 18 h, the crack width and crack area healing ratios for initial cracks within 600 μm were close to 100 %, and the resistance coefficient to water penetration improves by nearly 4 orders of magnitude. This study successfully extends the application scenarios of microbial self-healing of concrete.</div></div>","PeriodicalId":9865,"journal":{"name":"Cement & concrete composites","volume":"158 ","pages":"Article 105965"},"PeriodicalIF":10.8,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143083147","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}

引用次数: 0