Materials and Structures最新文献_第4页

Synthesis and characterization of metakaolin-based geopolymer systems under cyclic thermal exposure 循环热暴露下偏高岭土聚合物体系的合成与表征

IF 3.9 3区工程技术

Materials and Structures Pub Date : 2025-10-06 DOI: 10.1617/s11527-025-02816-5

Gabrielli Tápia, Sarah Danieli, Daniela Govoni Sotelo, Ivo Carvalho, Erich Rodríguez, Ana Paula Kirchheim

{"title":"Synthesis and characterization of metakaolin-based geopolymer systems under cyclic thermal exposure","authors":"Gabrielli Tápia, Sarah Danieli, Daniela Govoni Sotelo, Ivo Carvalho, Erich Rodríguez, Ana Paula Kirchheim","doi":"10.1617/s11527-025-02816-5","DOIUrl":"10.1617/s11527-025-02816-5","url":null,"abstract":"<div><p>Geopolymers are low-carbon binders that have garnered significant interest in the construction industry due to their potential in applications where Portland cement may not be the optimal choice, particularly in environments exposed to repeated high temperatures. While most existing studies have focused on single-heat exposure scenarios, predominantly assessing the behavior of geopolymers under fire-like conditions, a more comprehensive evaluation of their resistance to high temperatures and refractoriness requires testing under multiple heating cycles. Such testing is crucial to determine whether these materials can withstand repeated thermal stresses over time. In this context, the present study investigates the performance of metakaolin-based geopolymers subjected to 10 thermal cycles at 400, 600, 800, and 1000 °C. The formulations tested included varying alkali dosages (15% and 20% K<sub>2</sub>O) and SiO<sub>2</sub>/K<sub>2</sub>O silica modulus (Ms) of the alkaline solution ranging from 1.0 to 1.25. The results revealed a decrease in density and an increase in water absorption following thermal exposure. Although a significant strength loss was observed after the first cycle, the geopolymers demonstrated remarkable thermal stability between the first and tenth cycles. Depending on the formulation, the study suggests that geopolymers exhibit considerable resilience to high-temperature conditions, with water content playing a crucial role in the material’s thermal response and overall performance.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Uniformity and mechanical performance of recycled asphalt mixtures with high RAP content based on refined decomposition: a comparative study with conventional separation 基于精细分解的高RAP含量再生沥青混合料均匀性及力学性能与常规分离的比较研究

IF 3.9 3区工程技术

Materials and Structures Pub Date : 2025-10-04 DOI: 10.1617/s11527-025-02807-6

Ning Li, Zhinan Cheng, Wei Tang, Xiangyang Fan, Zhao Yi

{"title":"Uniformity and mechanical performance of recycled asphalt mixtures with high RAP content based on refined decomposition: a comparative study with conventional separation","authors":"Ning Li, Zhinan Cheng, Wei Tang, Xiangyang Fan, Zhao Yi","doi":"10.1617/s11527-025-02807-6","DOIUrl":"10.1617/s11527-025-02807-6","url":null,"abstract":"<div><p>In view of the challenges of limited natural resources and environmental pollution, recycled asphalt pavement (RAP) is increasingly utilized in asphalt mixtures. To enhance the utilization efficiency of RAP, it is essential to separate the aged asphalt from the aggregates within RAP. Currently, commonly used physical separation technologies include conventional separation as well as refined decomposition. The objective of this study is to compare the uniformity and mechanical performance of recycled asphalt mixtures (RAM) with high RAP content based on the 2 separation technologies. Firstly, RAP materials were pre-processed by these two technologies (named as RAP-CS and RAP-RD respectively), followed by the preparation of RAM with varying RAP contents. Subsequently, the uniformity of the RAM was evaluated by analyzing deviations in gradation and the asphalt-aggregate ratio. Furthermore, digital image processing (DIP) technology was employed to analyze the cross-sectional images of the compacted specimens of RAM. Finally, the mechanical performance of RAM were evaluated through dynamic modulus tests, dynamic creep loading tests and low-temperature semi-circular bending (SCB) tests. The correlation between the uniformity and mechanical performance of the RAM was analyzed. Results indicate that compared to RAP-CS, RAP-RD show superior uniformity in gradation and asphalt-aggregate ratio. Moreover, RAM prepared with RAP-RD shows superior aggregate dispersion uniformity and enhanced mechanical performance. Pearson correlation analysis revealed that better dispersion uniformity corresponded to lower dynamic modulus at low frequencies and higher values at high frequencies, greater axial strain and axial strain rate at elevated temperatures, and enhanced the low-temperature SCB strength.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145256076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 comprehensive database and a new model for the axial response of heat-damaged concrete before and after FRP confinement FRP围护前后热损伤混凝土轴向响应的综合数据库和新模型

IF 3.9 3区工程技术

Materials and Structures Pub Date : 2025-10-03 DOI: 10.1617/s11527-025-02791-x

Nefise Akdag, Ugur Demir

{"title":"A comprehensive database and a new model for the axial response of heat-damaged concrete before and after FRP confinement","authors":"Nefise Akdag, Ugur Demir","doi":"10.1617/s11527-025-02791-x","DOIUrl":"10.1617/s11527-025-02791-x","url":null,"abstract":"<div><p>In this study, a total of 330 concrete specimens, compiled from existing experimental data, are systematically reviewed to assess their post-fire axial stress–strain behavior before and after circumferential confinement with fiber-reinforced polymers (FRPs). The selection criteria for the database are as follows: (i) studies had to be published in English, (ii) both lateral and axial ultimate strains must have been measured, (iii) the use of additional strengthening materials in combination with FRPs was excluded, (iv) only plain concrete specimens were considered, and (v) specimen dimensions and instrumentation details had to be explicitly reported. The dataset is structured to include heating/cooling and curing conditions, specimen properties, and FRP characteristics. Subsequently, the predictive accuracy of available models for post-fire axial strength and ultimate strain of concrete members, both before and after FRP confinement, is evaluated. The results based on the reviewed comprehensive database indicate that these models are inadequate in capturing the observed behavior in the experiments. As such, a new analytical model is developed based on the compiled dataset. The proposed model demonstrated reliable predictive performance in terms of post-fire axial response of concrete before and after FRP confinement while remaining user-friendly for practical engineering applications. This is done such that universal design guidelines on the behavior of heat-damaged concrete strengthened by FRP composites can be reliably formulated.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210246","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Investigating the relationship between early-age elastic modulus development and setting time in cement-based materials 研究水泥基材料早期弹性模量发展与凝结时间的关系

IF 3.9 3区工程技术

Materials and Structures Pub Date : 2025-10-03 DOI: 10.1617/s11527-025-02800-z

Amir Araghi, José Granja, Renan Rocha Ribeiro, Miguel Azenha, Rodrigo Lameiras

{"title":"Investigating the relationship between early-age elastic modulus development and setting time in cement-based materials","authors":"Amir Araghi, José Granja, Renan Rocha Ribeiro, Miguel Azenha, Rodrigo Lameiras","doi":"10.1617/s11527-025-02800-z","DOIUrl":"10.1617/s11527-025-02800-z","url":null,"abstract":"<div><p>This study examines the applicability of early-age static elastic modulus measurements for estimating the setting time of cement-based materials. A range of cement paste compositions was prepared to encompass a broad spectrum of setting behaviors. Static elastic modulus was continuously and automatically monitored using a recently developed technique, Elasticity Modulus Measurement through Impulse Response Method (EMM-IRM), a variant of resonant frequency methods. For comparison, the Vicat Needle test was employed to determine setting times. The results indicate that the evolution of the elastic modulus over time is highly sensitive to variations in setting behavior. Notably, initial setting tends to correspond to the first inflection point of the time derivative of the static elastic modulus, while final setting aligns with the point where its rate of evolution levels off. Based on these observations, a new methodology is proposed for estimating setting times. In this approach, the initial setting corresponds to the first peak in the second derivative of the static elastic modulus curve, while the final setting is defined as the point at which this curve decreases to 80% of its maximum value.</p><h3>Graphical abstract</h3><div><figure><div><div><picture><source><img></source></picture></div></div></figure></div></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 9","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-10-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145204616","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Quantifying volcanic glass powder in cementitious systems using PONKCS-Rietveld analysis 定量火山玻璃粉胶凝体系使用PONKCS-Rietveld分析

IF 3.9 3区工程技术

Materials and Structures Pub Date : 2025-10-01 DOI: 10.1617/s11527-025-02796-6

Yuqi Ren, Zhenli Yang, Ryo Kurihara, Atsushi Tomoyose, Ippei Maruyama

{"title":"Quantifying volcanic glass powder in cementitious systems using PONKCS-Rietveld analysis","authors":"Yuqi Ren, Zhenli Yang, Ryo Kurihara, Atsushi Tomoyose, Ippei Maruyama","doi":"10.1617/s11527-025-02796-6","DOIUrl":"10.1617/s11527-025-02796-6","url":null,"abstract":"<div><p>Volcanic glass powder (VGP) has emerged as a promising supplementary cementitious material (SCM) due to its pozzolanic reactivity and potential to enhance the microstructure of cementitious systems. Accurate quantification of the VGP glass content is essential for understanding its reaction kinetics and optimizing its use in concrete. This study evaluates the efficiency and accuracy of the partial or no known crystal structures (PONKCS) method for quantifying VGP glass, offering a practical alternative to time-consuming selective dissolution experiments. Results show that the PONKCS-Rietveld analysis provides reliable quantification, with deviations within ± 2 wt.% compared to the selective dissolution method. In a simplified system of VGP mixed corundum, the method demonstrated high accuracy across a range of VGP glass contents, confirming its robustness under controlled conditions. However, in hydrated VGP–OPC systems, when the VGP content falls below 10 g/100 g ignited binder (corresponding to a VGP reaction degree of 40%), quantification errors increase due to changes in the full width at half maximum (FWHM) of the C-S-H peak at 29.4°, influenced by the pozzolanic reaction of VGP. These findings contribute to the refinement of PONKCS-Rietveld analysis for VGP glass, supporting its application in the precise evaluation of VGP-containing cementitious systems.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1617/s11527-025-02796-6.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Experimental investigation on fatigue properties of asphalt mixtures with high content of RAP and recycled plastics 高掺RAP与再生塑料沥青混合料疲劳性能试验研究

IF 3.9 3区工程技术

Materials and Structures Pub Date : 2025-09-29 DOI: 10.1617/s11527-025-02793-9

Joseph Nicolas La Macchia, Orazio Baglieri, Davide Dalmazzo, Ezio Santagata

{"title":"Experimental investigation on fatigue properties of asphalt mixtures with high content of RAP and recycled plastics","authors":"Joseph Nicolas La Macchia, Orazio Baglieri, Davide Dalmazzo, Ezio Santagata","doi":"10.1617/s11527-025-02793-9","DOIUrl":"10.1617/s11527-025-02793-9","url":null,"abstract":"<div><p>The experimental study described in the paper explored the synergistic effects of Reclaimed Asphalt Pavements (RAP) and a polymeric compound derived from recycled plastics on fatigue properties of dense-graded asphalt mixtures. The investigated mixtures were prepared in the laboratory by combining 50% of RAP with different dosages of the polymeric compound. A control mixture containing a highly SBS-modified binder was also prepared and tested for comparison purposes. The fatigue properties of mixtures were evaluated by means of flexural test in the four-point bending configuration under oscillatory loading. The tests were conducted in both controlled-stress and controlled-strain loading modes to understand the response of materials under different critical loading conditions in actual pavement structure. The experimental results indicated that the use of high percentages of RAP combined with the use of recycled plastics resulted in good fatigue performance of the mixture. The experimental data also indicated that recycled plastics at higher dosage used in this study yielded fatigue performance comparable or even slightly higher to that obtained with the use of control SBS-modified binder.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1617/s11527-025-02793-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210941","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Designing 3D printable concrete by integrating the influence of aggregate characteristics 结合集料特性的影响设计3D可打印混凝土

IF 3.9 3区工程技术

Materials and Structures Pub Date : 2025-09-29 DOI: 10.1617/s11527-025-02782-y

Spandana Paritala, Shubham Raj, Prashant R. Singh, Kolluru V. L. Subramaniam

{"title":"Designing 3D printable concrete by integrating the influence of aggregate characteristics","authors":"Spandana Paritala, Shubham Raj, Prashant R. Singh, Kolluru V. L. Subramaniam","doi":"10.1617/s11527-025-02782-y","DOIUrl":"10.1617/s11527-025-02782-y","url":null,"abstract":"<div><p>This study systematically investigates the effects of aggregate type, aggregate content, and paste rheology on the printability of concrete mixtures. The intricate relationship between printability, paste rheology, and excess paste content in concrete mixtures is investigated by incorporating three different types of aggregate. Concrete mixtures with higher yield stress paste demand greater amounts of excess paste to maintain the fluidity required for printability, thereby limiting the aggregate content. The binder content required to form the paste for filling voids between aggregate particles and coating their surface is determined by the packing density and the specific surface area of the aggregate. Interestingly, the study reveals that despite having higher packing density, if the aggregate type is characterized by high fine content and low sphericity, the mortar mixtures are printable only at very low aggregate content and require higher excess paste content. Aggregates with irregular shapes and large surface areas demand more paste to ensure flowability, overcome friction, and provide adequate coating, thereby affecting the overall printability of the mixture. Although a linear relationship between paste yield stress and excess paste content is observed in printable concrete mixtures, the relationship is found to vary with the aggregate type. A unique linear relationship is found between the yield stress of the paste and the ratio of paste volume fraction to the surface area of the aggregate normalized by the square of sphericity. This relationship is systematically validated across mixtures with multiple aggregate types, resulting in guidelines for proportioning the printable concrete mixtures. The paste requirement in printable concrete mixtures is determined by the yield stress of the paste and aggregate characteristics, including surface area and shape.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210693","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

Bleeding of Portland composite cements 波特兰复合水泥的出血

IF 3.9 3区工程技术

Materials and Structures Pub Date : 2025-09-29 DOI: 10.1617/s11527-025-02792-w

Adrian Chajec, Maciej Zając, Łukasz Sadowski

{"title":"Bleeding of Portland composite cements","authors":"Adrian Chajec, Maciej Zając, Łukasz Sadowski","doi":"10.1617/s11527-025-02792-w","DOIUrl":"10.1617/s11527-025-02792-w","url":null,"abstract":"<div><p>Bleeding remains a critical issue in the performance and durability of cementitious composites, particularly in systems incorporating mineral powders (MPs). This study investigates the bleeding behaviour of Portland cement pastes modified with granite powder (GP), limestone powder (LP), and siliceous fly ash (FA) at varying substitution levels (10–30 wt.%). A comprehensive experimental programme was designed to correlate bleeding intensity with the physical and morphological properties of the powders, including particle size distribution, specific surface area (BET), shape descriptors (Roundness, Area ratio, Aspect ratio), and density. Advanced monitoring techniques—ultrasonic pulse velocity (UPV) and electrical conductivity measurements—were employed to track structural changes during the first 100 min of hydration. The results demonstrate that bleeding is primarily governed by powder morphology and density, rather than early-age reactivity. Powders with angular grains and high specific surface area (e.g., GP and LP) effectively reduce bleeding through enhanced particle packing and accelerated structure formation, whereas FA—with its lower density and spherical morphology—significantly increases bleeding capacity. Strong linear correlations were identified between bleeding volume and both UPV and electrical conductivity, supporting their application as non-destructive indicators of water migration and early matrix consolidation. A five-phase mechanistic model describing the evolution of bleeding is proposed, integrating gravitational settling, hydration kinetics, and structural stiffening. The study highlights that proper bleeding control in sustainable cement systems requires not only chemical compatibility but a targeted optimisation of particle shape, size, and density. These insights offer practical implications for the formulation of low-bleed, eco-efficient binders incorporating industrial by-products.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://link.springer.com/content/pdf/10.1617/s11527-025-02792-w.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 shear connections for cold-formed steel and concrete composite beams: experimental assessment by push-out tests 冷弯型钢和混凝土组合梁的创新剪切连接：推出试验的试验评估

IF 3.9 3区工程技术

Materials and Structures Pub Date : 2025-09-29 DOI: 10.1617/s11527-025-02786-8

Talita L. Silva, Isabel B. Valente, André V. Malheiro, Joaquim A. O. Barros

{"title":"Innovative shear connections for cold-formed steel and concrete composite beams: experimental assessment by push-out tests","authors":"Talita L. Silva, Isabel B. Valente, André V. Malheiro, Joaquim A. O. Barros","doi":"10.1617/s11527-025-02786-8","DOIUrl":"10.1617/s11527-025-02786-8","url":null,"abstract":"<div><p>Shear connectors ensure the composite action in steel and concrete composite beams. This study investigates two innovative shear connection systems for cold-formed steel (CFS) and concrete composite beams: the HCO (Half-Circular Opening) and TBU (Triangular Bent-Up). These connections are made of cuts and bend-ups in the CFS profiles, eliminating the use of typical mechanical connectors (such as headed studs, screws, or bolts) and optimising the construction process. Push-out tests were conducted to evaluate the load-slip behaviour, connection type and the impact of the number of connectors. One group of specimens was tested without shear connections (the reference specimens). Results revealed significant differences in load-slip behaviour of the HCO and TBU specimens compared to that of the reference specimens. The HCO and TBU connections prevented a considerable drop in load capacity after the CFS-concrete interface bond failure, increased the load capacity and led to a higher characteristic slip. Increasing the number of connections improved the maximum load capacity and reduced the characteristic slip and load capacity per connection. The TBU specimens exhibited higher load capacity than the HCO specimens. The reference specimens suffered a bond failure at the CFS-concrete interface, while the HCO and TBU specimens failed due to a concrete failure that led to an interruption of the load-slip response of the proposed connection systems.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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

The impact of associated minerals in kaolinite clays on their physico-chemical characteristics for use as supplementary cementitious material 高岭石粘土中伴生矿物对其作为补充胶凝材料的理化特性的影响

IF 3.9 3区工程技术

Materials and Structures Pub Date : 2025-09-29 DOI: 10.1617/s11527-025-02790-y

Mehnaz Dhar, Shashank Bishnoi

{"title":"The impact of associated minerals in kaolinite clays on their physico-chemical characteristics for use as supplementary cementitious material","authors":"Mehnaz Dhar, Shashank Bishnoi","doi":"10.1617/s11527-025-02790-y","DOIUrl":"10.1617/s11527-025-02790-y","url":null,"abstract":"<div><p>Clays in their natural state are complex and often occur as mixtures of clay and non-clay minerals. Medium-grade kaolinite clays that are feasible for supplementary cementitious material (SCM) applications contain various associated minerals that can affect their behavior. This study explores how associated minerals viz., iron, illite and quartz impact the physical and chemical properties both raw and after calcination at 600 °C, 700 °C, 800 °C, 900 °C, and 1000 °C using thermal analysis, XRD, FTIR and pozzolanic reactivity techniques. The results show that associated minerals influence the crystallinity, specific surface area and water demand of kaolinite clays. Iron rich kaolinite clays are found to be highly disordered and show higher specific surface area and water demand than quartz rich clays. The effect of associated minerals on the formation temperature of metakaolin was also observed as iron rich kaolinite showed conversion at lower temperatures when compared to quartz rich kaolinite. The catalytic role of iron in the metakaolin formation is confirmed by its interaction with the kaolinite structure in model iron rich clay system using EPR technique. The optimal calcination temperature of kaolinite varies depending on the associated minerals and a positive effect of illite impurities on the pozzolanic reactivity of low-grade kaolinite clay has been observed.</p></div>","PeriodicalId":691,"journal":{"name":"Materials and Structures","volume":"58 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145210943","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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