CEMENT

Pub Date : 2025-07-27 DOI: 10.1016/j.cement.2025.100153

Cassandra Trottier , Laurent Ramos Cheret , Haoye Lu , Anthony Allard , Maia Fraser , Leandro F.M. Sanchez

The damage rating index (DRI) is a valuable microscopy tool for collecting and counting data on different types of concrete cracks, such as those associated with alkali-silica reaction (ASR) induced deterioration. Yet, the procedure presents drawbacks such as time consumption and variability linked to operator experience, which has sparked debates about the subjectivity of its outcomes. Embracing the forefront of technological advancements, this study explores the practicality of automating the DRI's data collection through artificial intelligence (AI) and machine learning. Like many image processing and analysis applications that use AI, the DRI is an object classification and segmentation task. This study represents a step forward in leveraging automation to enhance the objectivity and efficiency of ASR damage characterization in concrete through point-count microscopy, along with proposing a set of tools to evaluate the outcomes from the application’s perspective for more efficient training data selection. Results show that despite obtaining acceptable performance individually, where the detector-classifier performance was found to have an accuracy of 0.744, and the crack counter accuracy was 0.988, the current version of the proposed machine still displays high variability in detecting, classifying, and counting distinct crack types. Overall, the machine overestimates ASR-induced damage, which was further verified through the Chi-square goodness of fit test, indicating that further training and enhancement of the proposed machine are required.

损伤等级指数（DRI）是一种有价值的显微工具，用于收集和计数不同类型的混凝土裂缝数据，例如与碱-硅反应（ASR）引起的恶化有关的裂缝。然而，该方法存在一些缺点，如耗时和与操作人员经验相关的可变性，这引发了关于其结果主观性的争论。拥抱技术进步的前沿，本研究探索了通过人工智能（AI）和机器学习实现DRI数据收集自动化的可行性。像许多使用人工智能的图像处理和分析应用程序一样，DRI是一个对象分类和分割任务。这项研究代表了利用自动化技术通过点计数显微镜来提高混凝土ASR损伤表征的客观性和效率的一步，同时提出了一套工具来从应用程序的角度评估结果，以更有效地训练数据选择。结果表明，尽管单独获得了可接受的性能，其中检测器-分类器性能的准确率为0.744，裂纹计数器精度为0.988，但当前版本的机器在检测，分类和计数不同的裂纹类型方面仍然表现出很高的可变性。总的来说，机器高估了asr引起的损伤，卡方拟合优度检验进一步验证了这一点，表明需要进一步训练和增强所提出的机器。

{"title":"Enhancing efficiency in evaluating alkali-silica reaction (ASR) damage: an automated approach to point-count microscopy","authors":"Cassandra Trottier , Laurent Ramos Cheret , Haoye Lu , Anthony Allard , Maia Fraser , Leandro F.M. Sanchez","doi":"10.1016/j.cement.2025.100153","DOIUrl":"10.1016/j.cement.2025.100153","url":null,"abstract":"<div><div>The damage rating index (DRI) is a valuable microscopy tool for collecting and counting data on different types of concrete cracks, such as those associated with alkali-silica reaction (ASR) induced deterioration. Yet, the procedure presents drawbacks such as time consumption and variability linked to operator experience, which has sparked debates about the subjectivity of its outcomes. Embracing the forefront of technological advancements, this study explores the practicality of automating the DRI's data collection through artificial intelligence (AI) and machine learning. Like many image processing and analysis applications that use AI, the DRI is an object classification and segmentation task. This study represents a step forward in leveraging automation to enhance the objectivity and efficiency of ASR damage characterization in concrete through point-count microscopy, along with proposing a set of tools to evaluate the outcomes from the application’s perspective for more efficient training data selection. Results show that despite obtaining acceptable performance individually, where the detector-classifier performance was found to have an accuracy of 0.744, and the crack counter accuracy was 0.988, the current version of the proposed machine still displays high variability in detecting, classifying, and counting distinct crack types. Overall, the machine overestimates ASR-induced damage, which was further verified through the Chi-square goodness of fit test, indicating that further training and enhancement of the proposed machine are required.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"21 ","pages":"Article 100153"},"PeriodicalIF":0.0,"publicationDate":"2025-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144738408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Condition assessment of pre-tensioning prestressed concrete sleepers distressed by internal swelling reactions (ISR) 内膨胀反应（ISR）下预张预应力混凝土枕木状态评价

CEMENT

Pub Date : 2025-07-23 DOI: 10.1016/j.cement.2025.100154

R. Medeiros , D.J. De Souza , L.F.M. Sanchez , A.C. Santos

Concrete sleepers worldwide have been affected by internal swelling reactions (ISR), primarily alkali-silica reaction (ASR) and internal sulfate attack (ISA). While numerous studies have focused on diagnosing ISR-affected sleepers, most emphasize identifying the cause rather than estimating the extent of deterioration, which is critical for informed decision-making. This study presents a comprehensive condition assessment of concrete sleepers displaying numerous ages and environmental exposure conditions through visual inspection (i.e., crack measurements) followed by the implementation of the multi-level assessment protocol, composed of microscopic (i.e., damage rating index-DRI) and mechanical (i.e., stiffness damage test-SDT) testing procedures. Results evidenced the multi-level protocol efficiency in estimating the cause(s) (i.e., ASR+ISA), further confirmed through SEM-EDS analysis, and quantifying the deterioration extent. These findings reveal gaps in current specification to prevent ISR damage in new sleepers and the importance of considering environmental conditions in condition assessment of existing sleepers, demonstrating an urgent need to review specifications/protocols.

混凝土轨枕在世界范围内受到内部膨胀反应（ISR），主要是碱-硅反应（ASR）和内部硫酸盐侵蚀（ISA）的影响。虽然许多研究都集中在诊断受isr影响的睡眠者，但大多数研究都强调确定原因，而不是估计恶化的程度，这对明智的决策至关重要。本研究通过目视检查（即裂缝测量）对混凝土枕木进行了全面的状态评估，显示了许多年龄和环境暴露条件，随后实施了多层次评估方案，由微观（即损伤等级指数- dri）和力学（即刚度损伤测试- sdt）测试程序组成。结果证明了多级协议在估计原因（即ASR+ISA）方面的效率，并通过SEM-EDS分析进一步证实，并量化了恶化程度。这些发现揭示了当前规范在防止新枕木的ISR损伤方面存在的差距，以及在对现有枕木进行状态评估时考虑环境条件的重要性，表明迫切需要审查规范/协议。

{"title":"Condition assessment of pre-tensioning prestressed concrete sleepers distressed by internal swelling reactions (ISR)","authors":"R. Medeiros , D.J. De Souza , L.F.M. Sanchez , A.C. Santos","doi":"10.1016/j.cement.2025.100154","DOIUrl":"10.1016/j.cement.2025.100154","url":null,"abstract":"<div><div>Concrete sleepers worldwide have been affected by internal swelling reactions (ISR), primarily alkali-silica reaction (ASR) and internal sulfate attack (ISA). While numerous studies have focused on diagnosing ISR-affected sleepers, most emphasize identifying the cause rather than estimating the extent of deterioration, which is critical for informed decision-making. This study presents a comprehensive condition assessment of concrete sleepers displaying numerous ages and environmental exposure conditions through visual inspection (i.e., crack measurements) followed by the implementation of the multi-level assessment protocol, composed of microscopic (i.e., damage rating index-DRI) and mechanical (i.e., stiffness damage test-SDT) testing procedures. Results evidenced the multi-level protocol efficiency in estimating the cause(s) (i.e., ASR+ISA), further confirmed through SEM-EDS analysis, and quantifying the deterioration extent. These findings reveal gaps in current specification to prevent ISR damage in new sleepers and the importance of considering environmental conditions in condition assessment of existing sleepers, demonstrating an urgent need to review specifications/protocols.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"21 ","pages":"Article 100154"},"PeriodicalIF":0.0,"publicationDate":"2025-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144724954","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Non-aging basic creep of alkali-activated slag concrete: Multiscale characterization and modeling 碱活化矿渣混凝土的非老化基本徐变：多尺度表征与建模

CEMENT

Pub Date : 2025-07-20 DOI: 10.1016/j.cement.2025.100151

Richard Caron , Ravi A. Patel , Andreas Bogner , Frank Dehn

This study focuses on a multiscale characterization of basic creep behavior of two AAS creep mixes with high (hS) and low (lS) slag content, loaded at 28 days. Nano-indentation tests are performed to investigate creep properties of individual phases and classical creep tests to analyze the creep behavior of concrete. An analytical multiscale micromechanics-based model is applied to downscale creep properties of the reaction product foam at nano-scale to compare it with results from nano-indentation. The creep at nanoscale of reaction product foam is modeled with a compliance function considering only deviatoric component consisting of Kelvin–Voigt chain for short term behavior and logarithmic function to account for long-term behavior. Comparing downscaled compliance with creep modulus measured from nano-indentation it is concluded that nano-indentation captures long-term behavior of reaction product foam. In terms of two mix tested, while at nano-scale mix hS has a higher creep modulus, presence of more capillary porosity and micro-cracks counteracts this and as a result concrete with mix hS shows higher creep. The creep modulus of AAS product foam obtained from nano-indentation is significantly lower compared to the OPC products. Additionally, higher amount of gel water and fewer crystalline secondary products could explain higher creep observed for AAS concrete compared to OPC concrete.

本研究的重点是对两种高（hS）和低（lS）渣含量的AAS蠕变混合料在加载28天时的基本蠕变行为进行多尺度表征。采用纳米压痕试验研究了混凝土各相的徐变特性，采用经典徐变试验分析了混凝土的徐变特性。采用多尺度细观力学模型分析了反应产物泡沫在纳米尺度下的蠕变特性，并与纳米压痕结果进行了比较。用仅考虑由Kelvin-Voigt链组成的偏差分量的柔度函数和考虑长期行为的对数函数来模拟反应产物泡沫在纳米尺度上的蠕变。通过对比纳米压痕测量的蠕变模量和缩尺顺应性，得出纳米压痕能够捕获反应产物泡沫的长期行为的结论。两种配合比的试验结果表明，在纳米尺度下，hS配合比具有较高的徐变模量，但更多的毛管孔隙和微裂缝的存在抵消了这一作用，使得hS配合比混凝土表现出更高的徐变模量。纳米压痕制备的AAS产品泡沫的蠕变模量明显低于OPC产品。此外，较高的凝胶水量和较少的结晶二次产物可以解释AAS混凝土比OPC混凝土观察到的更高的徐变。

{"title":"Non-aging basic creep of alkali-activated slag concrete: Multiscale characterization and modeling","authors":"Richard Caron , Ravi A. Patel , Andreas Bogner , Frank Dehn","doi":"10.1016/j.cement.2025.100151","DOIUrl":"10.1016/j.cement.2025.100151","url":null,"abstract":"<div><div>This study focuses on a multiscale characterization of basic creep behavior of two AAS creep mixes with high (hS) and low (lS) slag content, loaded at 28 days. Nano-indentation tests are performed to investigate creep properties of individual phases and classical creep tests to analyze the creep behavior of concrete. An analytical multiscale micromechanics-based model is applied to downscale creep properties of the reaction product foam at nano-scale to compare it with results from nano-indentation. The creep at nanoscale of reaction product foam is modeled with a compliance function considering only deviatoric component consisting of Kelvin–Voigt chain for short term behavior and logarithmic function to account for long-term behavior. Comparing downscaled compliance with creep modulus measured from nano-indentation it is concluded that nano-indentation captures long-term behavior of reaction product foam. In terms of two mix tested, while at nano-scale mix hS has a higher creep modulus, presence of more capillary porosity and micro-cracks counteracts this and as a result concrete with mix hS shows higher creep. The creep modulus of AAS product foam obtained from nano-indentation is significantly lower compared to the OPC products. Additionally, higher amount of gel water and fewer crystalline secondary products could explain higher creep observed for AAS concrete compared to OPC concrete.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"21 ","pages":"Article 100151"},"PeriodicalIF":0.0,"publicationDate":"2025-07-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686535","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Comparisons of quarry by-products as a partial replacement of portland cement in pastes and mortars 采石场副产品在膏体和砂浆中部分替代波特兰水泥的比较

CEMENT

Pub Date : 2025-07-17 DOI: 10.1016/j.cement.2025.100152

Tu-Nam Nguyen , Michael Lowry , Thien Q. Tran , Ketki Phadke , Elizabeth Bise , Alexander S. Brand

Quarry by-products (QB), including screenings, pond fines, and baghouse fines, present a significant surplus, since they are not significantly utilized in other markets and industries. This study explores the use of seven different QB as direct replacements of limestone powder in a portland limestone cement for paste and mortar applications. Cement replacements ranging from 5 % to 20 % by volume were explored, and testing included compressive and flexural strengths, isothermal calorimetry, pore solution analysis, alkali-silica reaction, and reactivity analysis. Expectedly, the results demonstrated that not all QB yielded equivalent performance. All mortars with 5 % and 15 % QB substitution had lower compressive strengths than the control, with the 15 % QB substitution performing worse. However, the mortars with QB had higher flexural strengths than the control. The 5 %, 10 %, 15 %, and 20 % QB substitution samples decreased the cumulative heat at 24 h, 48 h, and 72 h, with a higher substitution having a stronger decreasing effect. QB 2 and QB 7 were found to only slightly decrease the cumulative heat at 5 % substitution. Furthermore, QB 2 was found to significantly accelerate the silicate and aluminate heat evolution peaks, while QB 1, QB 3, QB 4, QB 5, and QB 7 only slightly accelerated the silicate and/or aluminate peaks. The pore solution of mortars with 5 % and 15 % QB substitution were found to have a lower pH and, in general, increased calcium and silicon contents. QB 2 was found to be moderately ASR reactive, while QB 7 was found to be ASR reactive. All QB were found to be non-pozzolanic; however, they may still be of use in other portland cement applications.

采石场副产品（QB），包括筛分、池粉和袋粉，呈现出显著的盈余，因为它们在其他市场和工业中没有得到显著利用。本研究探讨了七种不同的QB作为石灰石粉在波特兰石灰石水泥中的直接替代品，用于膏体和砂浆应用。水泥替代量从5%到20%不等，测试包括抗压和抗弯强度、等温量热法、孔溶液分析、碱-硅反应和反应性分析。意料之中的是，结果表明并非所有QB都产生了相同的性能。5%和15% QB替代砂浆的抗压强度均低于对照，15% QB替代砂浆的抗压强度更差。但掺加QB的砂浆抗折强度高于对照。5%、10%、15%和20% QB取代的样品在24 h、48 h和72 h时降低累积热量，取代率越高，降低效果越强。qb2和qb7在5%的取代量下仅能略微降低累积热量。此外,QB 2被发现明显加快硅酸盐和铝酸盐放热峰,而QB 1, QB 3, QB 4、QB 5, QB 7稍微加快了硅酸铝酸和/或峰值。QB取代率为5%和15%的砂浆孔隙溶液pH值较低，钙和硅含量总体上有所增加。发现qb2具有中度ASR反应，而qb7具有ASR反应。所有QB均为非火山灰；然而，它们可能仍然在其他波特兰水泥应用中使用。

{"title":"Comparisons of quarry by-products as a partial replacement of portland cement in pastes and mortars","authors":"Tu-Nam Nguyen , Michael Lowry , Thien Q. Tran , Ketki Phadke , Elizabeth Bise , Alexander S. Brand","doi":"10.1016/j.cement.2025.100152","DOIUrl":"10.1016/j.cement.2025.100152","url":null,"abstract":"<div><div>Quarry by-products (QB), including screenings, pond fines, and baghouse fines, present a significant surplus, since they are not significantly utilized in other markets and industries. This study explores the use of seven different QB as direct replacements of limestone powder in a portland limestone cement for paste and mortar applications. Cement replacements ranging from 5 % to 20 % by volume were explored, and testing included compressive and flexural strengths, isothermal calorimetry, pore solution analysis, alkali-silica reaction, and reactivity analysis. Expectedly, the results demonstrated that not all QB yielded equivalent performance. All mortars with 5 % and 15 % QB substitution had lower compressive strengths than the control, with the 15 % QB substitution performing worse. However, the mortars with QB had higher flexural strengths than the control. The 5 %, 10 %, 15 %, and 20 % QB substitution samples decreased the cumulative heat at 24 h, 48 h, and 72 h, with a higher substitution having a stronger decreasing effect. QB 2 and QB 7 were found to only slightly decrease the cumulative heat at 5 % substitution. Furthermore, QB 2 was found to significantly accelerate the silicate and aluminate heat evolution peaks, while QB 1, QB 3, QB 4, QB 5, and QB 7 only slightly accelerated the silicate and/or aluminate peaks. The pore solution of mortars with 5 % and 15 % QB substitution were found to have a lower pH and, in general, increased calcium and silicon contents. QB 2 was found to be moderately ASR reactive, while QB 7 was found to be ASR reactive. All QB were found to be non-pozzolanic; however, they may still be of use in other portland cement applications.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"21 ","pages":"Article 100152"},"PeriodicalIF":0.0,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144686534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Modelling and visualizing the impact of metakaolin on the alkali concentration in cement paste pore solution 偏高岭土对水泥浆孔溶液中碱浓度影响的建模和可视化

CEMENT

Pub Date : 2025-06-11 DOI: 10.1016/j.cement.2025.100148

Ana Bergmann , Klaartje de Weerdt , Maxime Ranger , Miriam E. Krüger , Petter Hemstad , Barbara Lothenbach

This study investigates the effects of replacing Portland cement (PC) with metakaolin (MK) on the pore solution composition of cementitious binders. Using the empirical Taylor model and a thermodynamic model (GEMS), the required replacement levels of PC by MK are computed to achieve different threshold alkali metal concentrations. GEMS predicts that similar amounts of MK (15–20 %) are required regardless of w/b-ratio and PC alkali content, which does not match with the experimental evidence. The Taylor model captures better the effect of these variables, predicting replacement levels ranging from 0 to 40 %. Results are visualized through contour and 3D plots, highlighting the complex interactions and effects of SCMs on concrete durability.

本文研究了偏高岭土（MK）替代硅酸盐水泥（PC）对胶凝粘合剂孔隙溶液组成的影响。利用经验Taylor模型和热力学模型（GEMS），计算了达到不同阈值碱金属浓度所需的PC置换水平。GEMS预测，无论w/b比和PC碱含量如何，都需要相同数量的MK(15 - 20%)，这与实验证据不符。泰勒模型更好地捕捉了这些变量的影响，预测更替水平在0到40%之间。结果通过等高线和3D图可视化，突出了scm对混凝土耐久性的复杂相互作用和影响。

引用次数: 0

Cation uptake by fine aggregate in hardened cement mortar and its effect on electrical properties 水泥硬化砂浆中细骨料对阳离子的吸收及其对电性能的影响

CEMENT

Pub Date : 2025-06-01 DOI: 10.1016/j.cement.2025.100147

Atolo A. Tuinukuafe , Anuj Parashar , Xiaoqiang Hou , Jason H. Ideker

Electrical resistivity tests can be used to evaluate the transport properties of concrete and provide a durability assessment. However, the electrical resistivity is largely dependent on the pore solution composition and recent work suggests that some aggregates have the capacity for cation uptake. This study first aims to provide further evidence for adsorption of cations on aggregate surfaces, without formation of reaction products (e.g. alkali-silica reaction). Secondly, hardened mortar samples were prepared using a fine aggregate with a high alkali affinity and a non-reactive fine aggregate as a control. The electrical resistivity of mortars was measured, and the pore solution of these mortars was obtained through high-pressure extraction. The effect of aggregate moisture dilution on the pore solution was decoupled by using a pore partitioning model. The results indicate that aggregate minerology can influence the pore solution composition through cation uptake. Specific minerals of minor quantity, like biotite, may be responsible for cation exchange. While adsorbed cations strongly affected pore solution and formation factor measurement, the bulk resistivity measurements on hardened mortar were only marginally influenced. Research on other implications of similar aggregate interactions with pore solutions are an intriguing area for future research.

电阻率试验可用于评估混凝土的输送性能，并提供耐久性评估。然而，电阻率在很大程度上取决于孔隙溶液组成，最近的研究表明，一些聚集体具有阳离子吸收能力。本研究首先旨在提供进一步的证据，证明在不形成反应产物（如碱-硅反应）的情况下，阳离子在聚集体表面吸附。其次，以高碱亲和性细骨料和无反应性细骨料为对照，制备硬化砂浆样品。测定了砂浆的电阻率，并通过高压萃取得到了砂浆的孔隙溶液。利用孔隙分配模型解耦了骨料水分稀释对孔隙溶液的影响。结果表明，骨料矿物学通过阳离子吸收影响孔隙溶液组成。少量的特殊矿物，如黑云母，可能负责阳离子交换。虽然吸附阳离子对孔隙溶解度和地层系数的测量有强烈影响，但硬化砂浆的体电阻率测量仅受轻微影响。研究类似聚集体与孔隙溶液相互作用的其他含义是未来研究的一个有趣的领域。

{"title":"Cation uptake by fine aggregate in hardened cement mortar and its effect on electrical properties","authors":"Atolo A. Tuinukuafe , Anuj Parashar , Xiaoqiang Hou , Jason H. Ideker","doi":"10.1016/j.cement.2025.100147","DOIUrl":"10.1016/j.cement.2025.100147","url":null,"abstract":"<div><div>Electrical resistivity tests can be used to evaluate the transport properties of concrete and provide a durability assessment. However, the electrical resistivity is largely dependent on the pore solution composition and recent work suggests that some aggregates have the capacity for cation uptake. This study first aims to provide further evidence for adsorption of cations on aggregate surfaces, without formation of reaction products (e.g. alkali-silica reaction). Secondly, hardened mortar samples were prepared using a fine aggregate with a high alkali affinity and a non-reactive fine aggregate as a control. The electrical resistivity of mortars was measured, and the pore solution of these mortars was obtained through high-pressure extraction. The effect of aggregate moisture dilution on the pore solution was decoupled by using a pore partitioning model. The results indicate that aggregate minerology can influence the pore solution composition through cation uptake. Specific minerals of minor quantity, like biotite, may be responsible for cation exchange. While adsorbed cations strongly affected pore solution and formation factor measurement, the bulk resistivity measurements on hardened mortar were only marginally influenced. Research on other implications of similar aggregate interactions with pore solutions are an intriguing area for future research.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"20 ","pages":"Article 100147"},"PeriodicalIF":0.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144204389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Moisture dynamics and influence on alkali-silica reaction induced expansion: A comprehensive laboratory study 水分动力学及其对碱-硅反应诱发膨胀的影响：一项综合实验室研究

CEMENT

Pub Date : 2025-05-23 DOI: 10.1016/j.cement.2025.100146

O.D. Olajide , M.R. Nokken , L.F.M. Sanchez

Moisture availability is crucial for initiating and progressing alkali-silica reaction (ASR) in concrete. As a result, moisture control has often been adopted as a mitigation strategy in maintaining ASR-affected concrete. Selecting effective maintenance strategies requires a deep understanding of the moisture dynamics between internal moisture in concrete and its environment, and influence on ASR, which remains incompletely explored. To evaluate this interplay, 180 concrete cylinders incorporating a reference reactive aggregate (i.e., Spratt) were manufactured and stored at distinct conditions: i.e., three different temperatures (21°C, 38°C and 60°C) and five relative humidities (100 % RH, 90 % RH, 82 % RH, 75 % RH, and 62 % RH). The internal and external relative humidity, length, and mass change were monitored for up to a year. Results indicate that the amount of water used for cement hydration is sufficient to trigger the reaction, regardless of the subsequent exposure condition. However, the rate of ASR-induced development is influenced by the internal relative humidity, which changes with time based on the external relative humidity and temperature. Additionally, the minimum moisture (i.e., RH threshold) required to cause significant deleterious effects from ASR was assessed and confirmed to be temperature-dependent.

水分的可用性对于混凝土中碱-硅反应（ASR）的发生和发展至关重要。因此，在维护受asr影响的混凝土时，通常采用湿度控制作为缓解策略。选择有效的维护策略需要深入了解混凝土内部水分与其环境之间的水分动态，以及对ASR的影响，这方面的研究尚未完全深入。为了评估这种相互作用，制造了180个包含参考反应性骨料（即Spratt）的混凝土圆柱体，并在不同的条件下储存：即三种不同的温度（21°C， 38°C和60°C）和五种相对湿度（100% RH, 90% RH, 82% RH， 75% RH和62% RH）。内部和外部的相对湿度，长度和质量变化监测长达一年。结果表明，无论随后的暴露条件如何，用于水泥水化的水量足以引发反应。然而，asr诱发的发育速率受内部相对湿度的影响，内部相对湿度在外部相对湿度和温度的基础上随时间变化。此外，对引起ASR显著有害影响所需的最小湿度（即RH阈值）进行了评估，并确认其与温度有关。

{"title":"Moisture dynamics and influence on alkali-silica reaction induced expansion: A comprehensive laboratory study","authors":"O.D. Olajide , M.R. Nokken , L.F.M. Sanchez","doi":"10.1016/j.cement.2025.100146","DOIUrl":"10.1016/j.cement.2025.100146","url":null,"abstract":"<div><div>Moisture availability is crucial for initiating and progressing alkali-silica reaction (ASR) in concrete. As a result, moisture control has often been adopted as a mitigation strategy in maintaining ASR-affected concrete. Selecting effective maintenance strategies requires a deep understanding of the moisture dynamics between internal moisture in concrete and its environment, and influence on ASR, which remains incompletely explored. To evaluate this interplay, 180 concrete cylinders incorporating a reference reactive aggregate (i.e., Spratt) were manufactured and stored at distinct conditions: i.e., three different temperatures (21°C, 38°C and 60°C) and five relative humidities (100 % RH, 90 % RH, 82 % RH, 75 % RH, and 62 % RH). The internal and external relative humidity, length, and mass change were monitored for up to a year. Results indicate that the amount of water used for cement hydration is sufficient to trigger the reaction, regardless of the subsequent exposure condition. However, the rate of ASR-induced development is influenced by the internal relative humidity, which changes with time based on the external relative humidity and temperature. Additionally, the minimum moisture (i.e., RH threshold) required to cause significant deleterious effects from ASR was assessed and confirmed to be temperature-dependent.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"20 ","pages":"Article 100146"},"PeriodicalIF":0.0,"publicationDate":"2025-05-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154765","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Nanoscale pore structure analysis of cementitious materials subjected to delayed ettringite formation 延迟钙矾石形成胶凝材料的纳米级孔隙结构分析

CEMENT

Pub Date : 2025-05-15 DOI: 10.1016/j.cement.2025.100145

M. Shariful Islam , Yamini Shekar , Benjamin J. Mohr

The current study investigates the nanoscale pore structure of cementitious materials subjected to delayed ettringite formation (DEF) under different heat curing conditions up to 4000 days via small angle x-ray scattering (SAXS). Four types of commercially available cement were used and a heat-curing temperature of up to 100 °C was applied. Results indicated that the peak pore size deceased due to the initial ettringite formation filling up the largest pores. Over time, ettringite continues to form in the smallest pores during supersaturation, leading to an apparent increase in average pore size in later age. Once ettringite crystalline pressure exceed the tensile strength of the mortar, nano-cracking initiates. Results revealed that the critical pore size threshold necessary to induce cracking stress due to crystalline pressure in the microstructure was approximately 20 to 25 nm based on the SAXS analysis. The main outcome of this study was to recognize the pore size responsible for the mass expansions of certain mortars subjected to DEF under different heat curing conditions in the long-term of up to 4000 days.

本研究通过小角x射线散射（SAXS）研究了不同热固化条件下延迟钙矾石形成（DEF）胶凝材料的纳米级孔隙结构。使用了四种市售水泥，热固化温度高达100°C。结果表明，由于初始钙矾石充填了最大孔隙，峰值孔径减小。随着时间的推移，钙矾石继续在过饱和时最小的孔隙中形成，导致后期平均孔径明显增大。一旦钙矾石的结晶压力超过砂浆的抗拉强度，纳米裂缝就开始了。结果表明，基于SAXS分析，微观结构中由于结晶压力而产生裂纹应力所需的临界孔径阈值约为20 ~ 25 nm。本研究的主要结果是识别了在长达4000天的长期高温养护条件下，某些受DEF影响的砂浆的体积膨胀的孔径。

{"title":"Nanoscale pore structure analysis of cementitious materials subjected to delayed ettringite formation","authors":"M. Shariful Islam , Yamini Shekar , Benjamin J. Mohr","doi":"10.1016/j.cement.2025.100145","DOIUrl":"10.1016/j.cement.2025.100145","url":null,"abstract":"<div><div>The current study investigates the nanoscale pore structure of cementitious materials subjected to delayed ettringite formation (DEF) under different heat curing conditions up to 4000 days via small angle x-ray scattering (SAXS). Four types of commercially available cement were used and a heat-curing temperature of up to 100 °C was applied. Results indicated that the peak pore size deceased due to the initial ettringite formation filling up the largest pores. Over time, ettringite continues to form in the smallest pores during supersaturation, leading to an apparent increase in average pore size in later age. Once ettringite crystalline pressure exceed the tensile strength of the mortar, nano-cracking initiates. Results revealed that the critical pore size threshold necessary to induce cracking stress due to crystalline pressure in the microstructure was approximately 20 to 25 nm based on the SAXS analysis. The main outcome of this study was to recognize the pore size responsible for the mass expansions of certain mortars subjected to DEF under different heat curing conditions in the long-term of up to 4000 days.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"20 ","pages":"Article 100145"},"PeriodicalIF":0.0,"publicationDate":"2025-05-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144154764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermal, mechanical, and transport properties of C-S-H at the molecular scale: A force field benchmark 分子尺度上C-S-H的热、力学和输运性质：力场基准

CEMENT

Pub Date : 2025-05-12 DOI: 10.1016/j.cement.2025.100143

Tulio Honorio, Fatima Masara, Gang Huang, Farid Benboudjema

Interlayer species play a critical role in the thermo-hydro-mechanical properties of C-S-H at the molecular scale. We investigate how different choices in molecular modeling of C-S-H impact the behavior of interlayer species and subsequently affect the thermal, mechanical, and transport properties. By comparing various force fields, we identify the most effective approach per property. The choice of water force field has minimal influence on properties. As for heat capacity, we show that accounting for quantum corrections is important in calculating the thermal conductivity of C-S-H. Different choices of force fields lead to better agreement of estimates of the heat capacity, thermal conductivity, and thermal expansion of C-S-H with available experimental data. Non-reactive and reactive force fields exhibit similar behavior in tensile and shear tests. ClayFF Ca(aq) leads to a reduced interlayer diffusion coefficient. This research underscores the imperative role of accurately characterizing interlayer species in understanding C-S-H behavior.

在分子尺度上，层间物质对C-S-H的热-水-力学性能起着关键作用。我们研究了C-S-H分子模型的不同选择如何影响层间物质的行为，并随后影响热、力学和输运性质。通过比较不同的力场，我们确定了每个属性最有效的方法。水力场的选择对性能的影响最小。至于热容，我们表明在计算C-S-H的导热系数时，考虑量子修正是很重要的。不同的力场选择使得C-S-H的热容、导热系数和热膨胀的估计与现有的实验数据更加一致。非反作用力场和反作用力场在拉伸和剪切试验中表现出相似的行为。ClayFF Ca（aq）导致层间扩散系数降低。该研究强调了准确表征层间物种在理解C-S-H行为中的重要作用。

引用次数: 0

Influence of fineness modulus of fine aggregate on the durability properties of alkali-activated slag composites: An exprimental and statistical study 细骨料细度模量对碱活性矿渣复合材料耐久性能影响的实验与统计研究

CEMENT

Pub Date : 2025-04-24 DOI: 10.1016/j.cement.2025.100144

Adams Balade Abubakar, Waleed Hassan Khushefati

The consideration of sustainability has become a very important factor, because of the negative impacts posed by the production of Ordinary Portland Cement (OPC). This study investigates the influence of fine aggregate fineness modulus (FM) on the durability properties of AACs exposed to harsh environmental conditions (high temperatures, sea water, and sulfate solutions). Furthermore, this paper aims to statistically derive and validate a linear model that can be utilized in predicting the compressive strength (CS) of AACs of ground granulated blast furnace slag (GGBFS) using ultrasonic pulse velocity (UPV) a non-destructive evaluation. The FM of 2.4, 2.8, and 3.2, which represent fine, medium, and coarse particle sizes of fine aggregate, respectively, were adopted in this study, with other parameters kept constant. GGBFS was activated with a combined alkaline activating solution of sodium silicate (Na₂SiO₃) and a 12 M concentration of sodium hydroxide (NaOH) in a 2 to 1 ratio. The CS, UPV, density, and microstructural morphology as well as statistical analysis investigating linear relationships between UPV and CS were all evaluated in different harsh environments. The results showed that specimens immersed in 7 % magnesium sulfate (MgSO₄)and sea water after 6 months exhibited an increase in densities, CS, and UPV, with 2.4 FM having the highest enhancements, followed by 3.2 FM due to void filling action. However, mixes containing 2.8 FM were more resistant to residual incremental change produced by 7 % MgSO₄ and sea water. The statistical analysis shows that; besides the simplicity and robustness of the linear model, it also gives a higher coefficient of determination compared to an exponential model, making it a better fit for the UPV and CS relationship.

由于普通硅酸盐水泥（OPC）的生产所带来的负面影响，可持续性的考虑已成为一个非常重要的因素。本研究探讨了细骨料细度模量（FM）对暴露于恶劣环境条件（高温、海水和硫酸盐溶液）下的AACs耐久性的影响。此外，本文旨在统计推导并验证一个线性模型，该模型可用于利用超声脉冲速度（UPV）一种无损评价方法预测高炉磨粒渣AACs的抗压强度（CS）。本研究采用细骨料的细、中、粗粒度FM分别为2.4、2.8、3.2，其他参数保持不变。用水玻璃（Na2SiO3）和12 M浓度的氢氧化钠（NaOH）按2比1的比例组合碱性活化液活化GGBFS。在不同的恶劣环境下，CS、UPV、密度和微观结构形态以及调查UPV和CS之间线性关系的统计分析都进行了评估。结果表明，浸泡在7%硫酸镁（MgSO4）和海水中6个月后，样品的密度、CS和UPV均有所增加，其中2.4 FM增强最大，其次是3.2 FM，这是由于空隙填充作用。然而，含有2.8 FM的混合物更能抵抗7% MgSO4和海水产生的残余增量变化。统计分析表明；除了线性模型的简单性和鲁棒性外，与指数模型相比，它还具有更高的决定系数，使其更适合UPV和CS关系。

{"title":"Influence of fineness modulus of fine aggregate on the durability properties of alkali-activated slag composites: An exprimental and statistical study","authors":"Adams Balade Abubakar, Waleed Hassan Khushefati","doi":"10.1016/j.cement.2025.100144","DOIUrl":"10.1016/j.cement.2025.100144","url":null,"abstract":"<div><div>The consideration of sustainability has become a very important factor, because of the negative impacts posed by the production of Ordinary Portland Cement (OPC). This study investigates the influence of fine aggregate fineness modulus (FM) on the durability properties of AACs exposed to harsh environmental conditions (high temperatures, sea water, and sulfate solutions). Furthermore, this paper aims to statistically derive and validate a linear model that can be utilized in predicting the compressive strength (CS) of AACs of ground granulated blast furnace slag (GGBFS) using ultrasonic pulse velocity (UPV) a non-destructive evaluation. The FM of 2.4, 2.8, and 3.2, which represent fine, medium, and coarse particle sizes of fine aggregate, respectively, were adopted in this study, with other parameters kept constant. GGBFS was activated with a combined alkaline activating solution of sodium silicate (Na<sub>2</sub>SiO<sub>3</sub>) and a 12 M concentration of sodium hydroxide (NaOH) in a 2 to 1 ratio. The CS, UPV, density, and microstructural morphology as well as statistical analysis investigating linear relationships between UPV and CS were all evaluated in different harsh environments. The results showed that specimens immersed in 7 % magnesium sulfate (MgSO<sub>4</sub>)and sea water after 6 months exhibited an increase in densities, CS, and UPV, with 2.4 FM having the highest enhancements, followed by 3.2 FM due to void filling action. However, mixes containing 2.8 FM were more resistant to residual incremental change produced by 7 % MgSO<sub>4</sub> and sea water. The statistical analysis shows that; besides the simplicity and robustness of the linear model, it also gives a higher coefficient of determination compared to an exponential model, making it a better fit for the UPV and CS relationship.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"20 ","pages":"Article 100144"},"PeriodicalIF":0.0,"publicationDate":"2025-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143896085","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

CEMENT最新文献