Cement and Concrete Research最新文献

{"title":"Comparative evaluation of laboratory methods for performance assessment of cementitious materials in wastewater networks: Biological and chemical tests versus field exposure","authors":"Alexandra Bertron ,&nbsp;Cyrill Grengg ,&nbsp;Matthieu Peyre Lavigne ,&nbsp;Holger Wack ,&nbsp;Gregor J.G. Gluth ,&nbsp;Amr Aboulela ,&nbsp;Vanessa Sonois ,&nbsp;Tilman Gehrke ,&nbsp;Florian Mittermayr","doi":"10.1016/j.cemconres.2024.107741","DOIUrl":"10.1016/j.cemconres.2024.107741","url":null,"abstract":"<div><div>The biodeterioration of concrete elements in sewer systems and their repair is of significant economic and societal concern. However, the available test methods to assess the performance of cementitious materials under the relevant conditions are insufficiently validated. In the present study, two biological test methods and a standardised chemical test were applied to two sewer repair mortars and a reference mortar, and the performances of these materials were compared in a severely deteriorating sewer environment. In both biological tests, the induction period was considerably shorter than that of the field, and time-resolved recording of durability indicators enabled to determine deterioration rates in the steady-state regime, which compared reasonably well with each other and with the behaviour in the sewer environment. The chemical test does not allow to obtain a deterioration rate, and the observed relative performance differences of the mortars deviated from the results of the biological tests.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"188 ","pages":"Article 107741"},"PeriodicalIF":10.9,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142753009","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}

{"title":"Effect of flow rate on spatio-temporal deterioration of concrete under flowing sulfate attack","authors":"Fujian Yang ,&nbsp;Zhihao Zhao ,&nbsp;Yuan Liu ,&nbsp;Man Li ,&nbsp;Jinliang Song ,&nbsp;Dawei Hu ,&nbsp;Hui Zhou","doi":"10.1016/j.cemconres.2024.107734","DOIUrl":"10.1016/j.cemconres.2024.107734","url":null,"abstract":"<div><div>Flowing effect on concrete deterioration caused by sulfate attack at varying flow rates was studied. It was found that an increased flow rate can expedite the weakening of the concrete's elastic modulus in the short term, thus causing an earlier onset of this weakening. However, the long-term deterioration of the elastic modulus remains unaffected by the flow rate due to the limited amount of products responsible for concrete deterioration. Notably, the deterioration depth or rate of the elastic modulus increases with higher flow rates due to the scouring effect of sulfate flow. To quantify this acceleration effect, an acceleration coefficient was defined, representing the impact of flow rate on the weakening process of concrete. It is approximately 1.20 for every 0.5 m/s increase in flow rate within the tested range. This coefficient provides a useful metric to assess the durability of concrete to sulfate attack under varying flow conditions.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"188 ","pages":"Article 107734"},"PeriodicalIF":10.9,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142735673","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}

{"title":"Penetration test of sheet-like indenter for yield stress assessment of 3D-printed concrete","authors":"Haoyu Lu,&nbsp;Lizhi Zhang,&nbsp;Junkai Wang,&nbsp;Zhaoxin Shi,&nbsp;Wei She,&nbsp;Wenqiang Zuo","doi":"10.1016/j.cemconres.2024.107728","DOIUrl":"10.1016/j.cemconres.2024.107728","url":null,"abstract":"<div><div>The evolution of early mechanical properties of 3D-printed concrete (3DPC) plays a crucial role in early constructability, while current methods face challenges on the tradeoff between the accuracy and feasibility of mechanical properties characterization. In this paper, we designed a sheet-like indenter configuration to quantitatively obtain the yield stress of fresh 3DPC. First, we show the typical force-depth curve of sheet-like indenters obtained during the penetration test and analyze the main factors affecting the penetration resistance at various regimes. Then, we derive the quantitative correlation between the yield stress and the force-depth curve based on numerical simulation. Our results show that the slipping phenomenon between the indenter side and the material leads to an underestimation of the yield stress compared to the standard compression test and cone-shaped indenter. We moreover propose a sheet-like indenter with surface roughness modification to obtain the accurate yield stress value, together with a formula for the yield stress calculation based on the force-depth curve. Finally, we assess the feasibility of the proposed approach, which can robustly predict fresh 3DPC with yield stresses in the range of 1–100 kPa.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"188 ","pages":"Article 107728"},"PeriodicalIF":10.9,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142706203","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}

{"title":"Reaction and microstructure development of one-part geopolymer for wellbore applications – An experimental and numerical study","authors":"Mayank Gupta ,&nbsp;Xiujiao Qiu ,&nbsp;Mohamed Omran ,&nbsp;Yun Chen ,&nbsp;Mahmoud Khalifeh ,&nbsp;Guang Ye","doi":"10.1016/j.cemconres.2024.107738","DOIUrl":"10.1016/j.cemconres.2024.107738","url":null,"abstract":"<div><div>This study focuses on the numerical modeling of the reaction and microstructure development of a one-part granite-based geopolymer, which is often used for carbon capture and storage (CCS) applications. This work extends the capabilities of GeoMicro3D to model one-part geopolymers containing different precursors and activators (solid and in solution). The model considers the particle size distribution of different solids and the real shape of particles to prepare the initial simulation domain. Further, the dissolution rates of different solids estimated from the experiments were used to model the dissolution of different elements in the pore solution. Subsequently, the model utilizes classical nucleation probability modeling coupled with thermodynamic modeling to estimate the precipitation of products in the microstructure. Experiments were performed to study the pore solution, reaction degree, and amount of products in the microstructure, which were further compared with the simulation results to check the rationality of the model.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"188 ","pages":"Article 107738"},"PeriodicalIF":10.9,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718565","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}

{"title":"Quantitative relationship between microstructure of steel-concrete interface and chloride-induced corrosion rate of steel in unsaturated cementitious materials","authors":"Zushi Tian,&nbsp;Xiaojuan Kang,&nbsp;Haodong Ji,&nbsp;Hailong Ye","doi":"10.1016/j.cemconres.2024.107736","DOIUrl":"10.1016/j.cemconres.2024.107736","url":null,"abstract":"<div><div>While extensive evidence indicates that the porous microstructure of the steel-concrete interface (SCI) is the key factor contributing to early depassivation and expedited corrosion propagation of steel rebar, there remains a lack of quantitative relationship between the SCI microstructural parameters and corrosion rate of steel, particularly under unsaturated conditions. In this work, the effects of rebar arrangement direction (i.e., horizontal and vertical orientations), binder type (i.e., ordinary Portland cement and alkali-activated slag), presence of aggregate, and chloride content, on both the SCI and chloride-induced corrosion rate of steel were systematically investigated and quantified at different relative humidity levels. The results indicated that in comparison with Portland cement counterparts, the reaction products of alkali-activated slag fill the gap under the horizontally oriented steel rebars, favoring more densified SCI microstructure and better corrosion protection. Quantitative analysis reveals that in the unsaturated state, the corrosion rate of steel decreases more slowly in more porous SCI microstructure. An image-based model is proposed to quantitatively link SCI microstructure and corrosion rate of steel, which is applicable to both Portland cement and alkali-activated slag systems in saturated and unsaturated conditions.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"188 ","pages":"Article 107736"},"PeriodicalIF":10.9,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696506","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}

{"title":"Rheology dependent pore structure optimization of high-performance foam concrete","authors":"Dingqiang Fan ,&nbsp;Chunpeng Zhang ,&nbsp;Jian-Xin Lu ,&nbsp;Ligang Peng ,&nbsp;Rui Yu ,&nbsp;Chi Sun Poon","doi":"10.1016/j.cemconres.2024.107737","DOIUrl":"10.1016/j.cemconres.2024.107737","url":null,"abstract":"<div><div>Foam concrete encounters a fundamental challenge in balancing lightweight and high strength. Pore optimization is the key to address this problem. This study starts with rheology control to optimize the pore structure of foam concretes, thereby designing high-performance foam concrete (HPFC). X-ray computed tomography was employed to explore the relationship between rheology and pore characteristics, revealing the corresponding control mechanisms. The findings indicated that rheological parameters, particularly viscosity, significantly influenced pore size, uniformity, sphericity, fractal dimension and connectivity. Therefore, there was an optimal viscosity range (1.30 ± 0.15 Pa·s) for achieving the desirable pore structure. Mechanical analysis demonstrated that the viscosity could impact the balance of the added foams under dynamic and static conditions via drag force, resulting in changes to the pore structure. After pore optimization, the HPFCs exhibited high compressive strength (2–3 times higher than normal foam concrete at an equal density) and excellent durability comparable to high-performance concrete.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"188 ","pages":"Article 107737"},"PeriodicalIF":10.9,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142696507","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}

{"title":"Reactive transport modelling of autogenous self-healing in cracked concrete","authors":"Daniel Lahmann,&nbsp;Sylvia Keßler","doi":"10.1016/j.cemconres.2024.107733","DOIUrl":"10.1016/j.cemconres.2024.107733","url":null,"abstract":"<div><div>Autogenous self-healing can close cracks in water-retaining concrete structures. However, its inconsistent efficiency in building practice indicates that the underlying processes are not fully understood. Therefore, this study characterizes reactive transport through cracked concrete and models it using PHREEQC to develop a comprehensive understanding of chemical processes promoting autogenous self-healing. Driven by the dissolution of portlandite, the main cause of healing is the precipitation of CaCO₃, which contributes to a crack closure of up to 113 μm. This process is supported by the formation of M-S-H and C-S-H. As self-healing progresses, the rates of dissolution and precipitation processes that promote healing decrease exponentially. At initial flow rates &gt;2 L h⁻¹, CaCO₃ precipitation is favored towards the crack outlet. At lower initial flow rates, the formation of CaCO₃ shifts towards the crack inlet. These findings underscore the need to reconsider the reliance on effective healing in practical applications.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"187 ","pages":"Article 107733"},"PeriodicalIF":10.9,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678319","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}

{"title":"Rheology control of cement paste by in-situ polymerization for 3D printing applications","authors":"Zhaoyang Sun ,&nbsp;Yuyang Zhao ,&nbsp;Dongshuai Hou ,&nbsp;Zongjin Li ,&nbsp;Binmeng Chen","doi":"10.1016/j.cemconres.2024.107731","DOIUrl":"10.1016/j.cemconres.2024.107731","url":null,"abstract":"<div><div>Rheology control is the most critical determinant of success in 3D concrete printing (3DCP), typically achieved through the hydration control of cement. However, this inevitably leads to overdesign of printed concrete featuring a low water-to-binder ratio (w/b), which is incompatible with its non-load bearing purpose and raises a series of environmental and durability problems, such as high carbon footprint and early-age shrinkage. Herein, we propose a novel rheology control strategy via in-situ polymerization, allowing the mix design of printed concrete with a high w/b ratio of 0.6. The proposed approach consists of two stages: 1) introducing monomers as retarders to extend the open time during pumping, and 2) incorporating initiators into the mixture to trigger polymerization, facilitating the structural build-up after deposition by forming polymer bridges between cement particles. We show that the addition of monomers significantly retards yield stress growth, while the following in-situ polymerization engenders a rapid strength development, satisfying the rheological requirements for 3DCP. Mechanistic experiments reveal that the retarding effect results from the complexation of monomers with aqueous species, such as Ca²⁺ ions, thereby hindering the nucleation of hydrates. As polymerization initiates, the impetus for the structural build-up of the cement pastes first originates from the proliferation of polymer bridges due to the gradual formation and adsorption of polymer, and then relies on the reinforcement of these polymer bridges through the formation of chemical bonds or crosslinks. On top of the environmental benefit, the proposed strategy holds the potential in avoiding admixtures conflict, mitigating early-age shrinkage, and improving mechanical properties. Our strategy opens possibilities for a novel technical route to achieve rheology control of 3DCP, and the discovery in this work will be a landmark for revealing the mechanism of 3DCP via in-situ polymerization.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"187 ","pages":"Article 107731"},"PeriodicalIF":10.9,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142684179","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}

{"title":"Modelling and experimental study on static yield stress evolution and structural build-up of cement paste in early stage of cement hydration","authors":"Yanliang Ji ,&nbsp;Ursula Pott ,&nbsp;Alexander Mezhov ,&nbsp;Christiane Rößler ,&nbsp;Dietmar Stephan","doi":"10.1016/j.cemconres.2024.107710","DOIUrl":"10.1016/j.cemconres.2024.107710","url":null,"abstract":"<div><div>Static yield stress is crucial for concrete, especially for 3D printed concrete, as it determines whether the bottom layer can support the load of the subsequent layers or withstand any potential impulses. A better understanding of the evolution of the static yield stress and its changing mechanism is therefore needed. Under the assumption that hydrate formation follows fractal patterns, this work proposes a model for simulating static yield stress that links the hydration process and bridging possibility. To validate the model, parameters were first obtained from the BNG (Boundary Nucleation Growth) equation fitted with calorimetry data, and the relation of associated hydration rates to sound speed variation rate was analyzed. Results showed that the proposed model predicts well the static yield stress obtained with a penetration test, under varying water-cement ratios and accelerator conditions. The fitted parameter β was found to correlate with size and morphology of the hydration products, suggesting that the model can not only simulate the static yield stress, but also capture the structural build-up information. Furthermore, the decrease in fractal-related β implies that more compact hydrates are formed during hydration.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"187 ","pages":"Article 107710"},"PeriodicalIF":10.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673383","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}

{"title":"A new model for investigating the formation of interfacial transition zone in cement-based materials","authors":"Xuan Gao ,&nbsp;Qing-feng Liu ,&nbsp;Yuxin Cai ,&nbsp;Liang-yu Tong ,&nbsp;Zesen Peng ,&nbsp;Qing Xiang Xiong ,&nbsp;Geert De Schutter","doi":"10.1016/j.cemconres.2024.107675","DOIUrl":"10.1016/j.cemconres.2024.107675","url":null,"abstract":"<div><div>The interfacial transition zone (ITZ), located between aggregate and cement paste, has the features of high porosity, low unhydrated cement content, and enrichment of calcium hydroxide crystals (CH) and is often regarded as the weak link in cement-based materials. The present study is devoted to investigating the influence of multiple mechanisms or factors on ITZ formation, including the wall effect, ion transport, and aggregate features. A new modelling system is proposed to assess the interactions between these mechanisms or factors. The time-spatial distribution of hydration products and pores is studied by considering the reaction-diffusion-crystallization process of a non-uniformly distributed cement. Based on the developed model, the effects of individual mechanisms and their interactions on ITZ formation were clarified. The results indicated that the wall effect would determine the spatial distribution of cement and most hydration products due to the repulsion of aggregates on cement particles. The ion transport would influence the time evolution and redistribution of hydration products, which couples with the role of the wall effect. It was also found that aggregate features, including spacing and surface roughness, can affect the distribution of cement and the heterogeneity of cement-based materials, which works synergistically with the wall effect.</div></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"187 ","pages":"Article 107675"},"PeriodicalIF":10.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678321","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}