Pub Date : 2025-06-01Epub Date: 2025-05-12DOI: 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.
{"title":"Thermal, mechanical, and transport properties of C-S-H at the molecular scale: A force field benchmark","authors":"Tulio Honorio, Fatima Masara, Gang Huang, Farid Benboudjema","doi":"10.1016/j.cement.2025.100143","DOIUrl":"10.1016/j.cement.2025.100143","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"20 ","pages":"Article 100143"},"PeriodicalIF":0.0,"publicationDate":"2025-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144083920","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}
Pub Date : 2025-06-01Epub Date: 2025-05-15DOI: 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.
{"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":"2025-06-01","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}
Pub Date : 2025-03-01Epub Date: 2025-02-04DOI: 10.1016/j.cement.2025.100134
Nicholas Benjamin Petersen , Ashish Bastola , Pavan Akula , John Rushing
Rapid stabilization of weak soil offers a promising option for quick infrastructure development and soil repair. The interaction between the rapid stabilizer and the soil is critical in defining its strength and durability. This study investigates the physicochemical effects of using Calcium Sulfoaluminate (CSA) cement-based stabilizers for rapid stabilization of weak clays, focusing on early age (<1 day) reaction kinetics and its effect on the short-term and long-term engineering characteristics. Geochemical modeling is proposed to model the chemical kinetics and predict the formation of strength-enhancing products in the stabilized soil mixtures. The study investigates the unconfined compression strength and durability (cyclic wetting and drying) of stabilized soil. Results showed stabilizers with a higher proportion (50 wt. percentage or more) of CSA (CSA-rich) achieved up to 80 % of the 28–day strength in 60 min after stabilization. Mineralogical characterization using X-Ray Diffraction, Thermogravimetric Analysis, and Scanning Electron Microscopy, identified Ettringite in CSA-rich stabilizers and Calcium-Silicate-Hydrates (C-S-H) in stabilizers with a higher (50 wt. percentage or more) proportion of Portland Cement (PC-rich) stabilizers as key strength-enhancing products. Integrating the modeling results with the engineering and mineralogical characterization provided valuable insights into the rapid stabilization mechanisms of CSA cement.
{"title":"Physicochemical kinetics of rapid soil stabilization using calcium sulfoaluminate-based cements","authors":"Nicholas Benjamin Petersen , Ashish Bastola , Pavan Akula , John Rushing","doi":"10.1016/j.cement.2025.100134","DOIUrl":"10.1016/j.cement.2025.100134","url":null,"abstract":"<div><div>Rapid stabilization of weak soil offers a promising option for quick infrastructure development and soil repair. The interaction between the rapid stabilizer and the soil is critical in defining its strength and durability. This study investigates the physicochemical effects of using Calcium Sulfoaluminate (CSA) cement-based stabilizers for rapid stabilization of weak clays, focusing on early age (<1 day) reaction kinetics and its effect on the short-term and long-term engineering characteristics. Geochemical modeling is proposed to model the chemical kinetics and predict the formation of strength-enhancing products in the stabilized soil mixtures. The study investigates the unconfined compression strength and durability (cyclic wetting and drying) of stabilized soil. Results showed stabilizers with a higher proportion (50 wt. percentage or more) of CSA (CSA-rich) achieved up to 80 % of the 28–day strength in 60 min after stabilization. Mineralogical characterization using X-Ray Diffraction, Thermogravimetric Analysis, and Scanning Electron Microscopy, identified Ettringite in CSA-rich stabilizers and Calcium-Silicate-Hydrates (C-S-H) in stabilizers with a higher (50 wt. percentage or more) proportion of Portland Cement (PC-rich) stabilizers as key strength-enhancing products. Integrating the modeling results with the engineering and mineralogical characterization provided valuable insights into the rapid stabilization mechanisms of CSA cement.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"19 ","pages":"Article 100134"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143348518","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2024-12-20DOI: 10.1016/j.cement.2024.100127
Pitabash Sahoo, Souradeep Gupta
Excavated soil from construction and demolition activities can be stabilized by alkali-activated binders to manufacture low-carbon construction materials. This research attempts to investigate the efficacy of non-sonicated (S) and sonicated sucrose (USS) as a controlled retarder in alkali-activated materials containing excavated lateritic soil (EAAM) (clay content of 42.5 %). Influences of sucrose dosage and sonication on hydration kinetics, setting, and structural build-up of EAAM have been investigated. Findings from isothermal calorimetry show 30 – 65 % retardation in hydration kinetics leading to a 50 – 60 % delay in setting and slower structural build-up of EAAM during the initial 12 h. This results in higher flowability and superior flow retention for longer duration than the control (0 % sucrose). By decoupling the effect on hydration of GGBS and FA, it is found that sucrose has a more dominant retarding effect on GGBS compared to FA, attributed to its stronger interaction with calcium-rich sites than aluminates. The addition of 2 % USS to EAAM results in higher retardation compared to 2 %S. This is attributed to the formation of acidic byproducts due to sonication-induced breakdown of sucrose molecules, leading to reduced pH and electrostatic repulsion. The densified microstructure of EAAM with USS compared to that with S results in a noticeable improvement in strength retention under wet conditions, suggesting reduced moisture sensitivity. Due to enhanced hydration at later ages, sucrose-EAAM possesses 30 – 48 % higher wet compressive strength than the control EAAM at the 28-day mark. Overall, sucrose, which can be prepared from waste biomass through “green” processes, can be a potential chemical admixture for earth-based alkali-activated constructions.
{"title":"Effect of ultrasonication on sucrose structure and its influence on controlled retardation of earth-based alkali-activated materials","authors":"Pitabash Sahoo, Souradeep Gupta","doi":"10.1016/j.cement.2024.100127","DOIUrl":"10.1016/j.cement.2024.100127","url":null,"abstract":"<div><div>Excavated soil from construction and demolition activities can be stabilized by alkali-activated binders to manufacture low-carbon construction materials. This research attempts to investigate the efficacy of non-sonicated (S) and sonicated sucrose (USS) as a controlled retarder in alkali-activated materials containing excavated lateritic soil (EAAM) (clay content of 42.5 %). Influences of sucrose dosage and sonication on hydration kinetics, setting, and structural build-up of EAAM have been investigated. Findings from isothermal calorimetry show 30 – 65 % retardation in hydration kinetics leading to a 50 – 60 % delay in setting and slower structural build-up of EAAM during the initial 12 h. This results in higher flowability and superior flow retention for longer duration than the control (0 % sucrose). By decoupling the effect on hydration of GGBS and FA, it is found that sucrose has a more dominant retarding effect on GGBS compared to FA, attributed to its stronger interaction with calcium-rich sites than aluminates. The addition of 2 % USS to EAAM results in higher retardation compared to 2 %S. This is attributed to the formation of acidic byproducts due to sonication-induced breakdown of sucrose molecules, leading to reduced pH and electrostatic repulsion. The densified microstructure of EAAM with USS compared to that with S results in a noticeable improvement in strength retention under wet conditions, suggesting reduced moisture sensitivity. Due to enhanced hydration at later ages, sucrose-EAAM possesses 30 – 48 % higher wet compressive strength than the control EAAM at the 28-day mark. Overall, sucrose, which can be prepared from waste biomass through “green” processes, can be a potential chemical admixture for earth-based alkali-activated constructions.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"19 ","pages":"Article 100127"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152059","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2025-01-27DOI: 10.1016/j.cement.2025.100132
Wena de Nazaré do Rosário Martel, Josée Duchesne, Benoît Fournier
The growing use of alkali-rich glass powder (GP) as a supplementary cementitious material (SCM) in concrete has led to a rising number of studies focused on the microstructure of cementitious matrices incorporating GP. Electron probe microanalyzer (EPMA) is commonly used to characterize cementitious materials. However, alkali migration induced by electron irradiation - a well-known phenomenon in inorganic materials - remains underexplored in this context. This migration often leads to underestimation of Na and K and overestimation of Si and Ca, thus compromising the analysis of key elements in cementitious hydrates, such as C-S-H. Due to the lack of a tailored protocol for EPMA analysis of alkali-rich SCMs, this study established analytical conditions to minimize errors in quantifying pozzolanic GP. Mixed glass culets and GP particles embedded in 7-year-old ternary concrete made with GP and silica fume were analyzed using ten different current densities by varying beam size, current, and the sub-counting method. The results show that alkali migration is highly sensitive to material composition and irradiation conditions. Na losses exceeded 70% as Ca and Si overestimation reached approximately 13% at current densities above 0.354 nA/μm². Literature-reported densities often surpass this threshold. At those conditions, the implementation of a sub-counting method effectively reduces the Na loss to 3%. However, it introduced a tendency for Na overestimation at lower current densities. Among all conditions, a beam diameter of 6 µm and a current of 10 nA, was the most accurate, reducing losses to under 2% and closely matching the reference glass analysis.
随着富碱玻璃粉（GP）作为一种补充胶凝材料（SCM）在混凝土中的应用越来越广泛，越来越多的研究关注于含GP的胶凝基质的微观结构。电子探针微量分析仪（EPMA）是一种常用的胶凝材料表征方法。然而，电子辐照引起的碱迁移——无机材料中一个众所周知的现象——在这方面仍未得到充分的研究。这种迁移往往导致Na和K的低估和Si和Ca的高估，从而影响了胶结水合物中关键元素（如C-S-H）的分析。由于缺乏适合富碱SCMs的EPMA分析方案，本研究建立了分析条件，以尽量减少定量火山灰GP的误差。混合玻璃碎片和GP颗粒嵌入在由GP和硅灰制成的7年的三元混凝土中，通过不同的光束大小，电流和子计数方法，使用十种不同的电流密度进行分析。结果表明，碱迁移对材料组成和辐照条件高度敏感。当电流密度大于0.354 Na /μ²时，Ca和Si的高估约为13%，Na损失超过70%。文献报道的密度经常超过这个阈值。在这些条件下，子计数方法的实施有效地将Na损耗降低到3%。然而，在较低的电流密度下，它引入了Na高估的趋势。在所有条件下，光束直径为6µm，电流为10 nA是最准确的，将损耗降低到2%以下，与参考玻璃分析结果非常吻合。
{"title":"Optimization of microprobe analysis of cementitious materials incorporating glass powder under electron beam to avoid alkali migration","authors":"Wena de Nazaré do Rosário Martel, Josée Duchesne, Benoît Fournier","doi":"10.1016/j.cement.2025.100132","DOIUrl":"10.1016/j.cement.2025.100132","url":null,"abstract":"<div><div>The growing use of alkali-rich glass powder (GP) as a supplementary cementitious material (SCM) in concrete has led to a rising number of studies focused on the microstructure of cementitious matrices incorporating GP. Electron probe microanalyzer (EPMA) is commonly used to characterize cementitious materials. However, alkali migration induced by electron irradiation - a well-known phenomenon in inorganic materials - remains underexplored in this context. This migration often leads to underestimation of Na and K and overestimation of Si and Ca, thus compromising the analysis of key elements in cementitious hydrates, such as C-S-H. Due to the lack of a tailored protocol for EPMA analysis of alkali-rich SCMs, this study established analytical conditions to minimize errors in quantifying pozzolanic GP. Mixed glass culets and GP particles embedded in 7-year-old ternary concrete made with GP and silica fume were analyzed using ten different current densities by varying beam size, current, and the sub-counting method. The results show that alkali migration is highly sensitive to material composition and irradiation conditions. Na losses exceeded 70% as Ca and Si overestimation reached approximately 13% at current densities above 0.354 nA/μm². Literature-reported densities often surpass this threshold. At those conditions, the implementation of a sub-counting method effectively reduces the Na loss to 3%. However, it introduced a tendency for Na overestimation at lower current densities. Among all conditions, a beam diameter of 6 µm and a current of 10 nA, was the most accurate, reducing losses to under 2% and closely matching the reference glass analysis.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"19 ","pages":"Article 100132"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2025-01-14DOI: 10.1016/j.cement.2025.100128
Pegah Farjad , Ahmed G. Mehairi , Fereshteh Meshkani , Roozbeh Mowlaei , Rahil Khoshnazar , Nashaat N. Nassar
Nanosilica particles are among the most studied nanomaterials in cementitious mixtures. However, literature on the effect of nanosilica particle size on the performance of these mixtures is still limited, with sometimes inconsistent findings. This study aims to address this gap by including the synthesis and application of different-sized nanosilica particles in one study. A uniform synthesis method was used to achieve nanosilica with four distinct average particle sizes (10, 35, 65, and 90 nm), covering the whole nanoscale range. The nanosilica particles were then fully characterized and utilized in cement paste at 1, 2, and 3 wt% of the cement. The compressive strength, heat evolution, microstructure, and rheological behaviour of the resultant pastes were investigated. The results revealed that the smallest particle size of nanosilica (10 nm) provided the highest compressive strength enhancement (over 100 % enhancement when used at 2 wt% of cement). The high pozzolanic reactivity of such small nanosilica particles at 2 wt%, together with their acceleration effect on cement hydration and densification of the paste microstructure, all contributed to this strength improvement. Overall, the enhancing effects of the nanosilica particles on the compressive strength of the pastes were less substantial when their particle size increased from 10 to 90 nm at any given concentration. All the nanosilica particles also increased the viscosity of the paste. This increasing effect was higher for smaller-sized nanosilica particles and at higher concentrations.
{"title":"Compressive strength and microstructural development of cement paste incorporating nanosilica with different particle sizes","authors":"Pegah Farjad , Ahmed G. Mehairi , Fereshteh Meshkani , Roozbeh Mowlaei , Rahil Khoshnazar , Nashaat N. Nassar","doi":"10.1016/j.cement.2025.100128","DOIUrl":"10.1016/j.cement.2025.100128","url":null,"abstract":"<div><div>Nanosilica particles are among the most studied nanomaterials in cementitious mixtures. However, literature on the effect of nanosilica particle size on the performance of these mixtures is still limited, with sometimes inconsistent findings. This study aims to address this gap by including the synthesis and application of different-sized nanosilica particles in one study. A uniform synthesis method was used to achieve nanosilica with four distinct average particle sizes (10, 35, 65, and 90 nm), covering the whole nanoscale range. The nanosilica particles were then fully characterized and utilized in cement paste at 1, 2, and 3 wt% of the cement. The compressive strength, heat evolution, microstructure, and rheological behaviour of the resultant pastes were investigated. The results revealed that the smallest particle size of nanosilica (10 nm) provided the highest compressive strength enhancement (over 100 % enhancement when used at 2 wt% of cement). The high pozzolanic reactivity of such small nanosilica particles at 2 wt%, together with their acceleration effect on cement hydration and densification of the paste microstructure, all contributed to this strength improvement. Overall, the enhancing effects of the nanosilica particles on the compressive strength of the pastes were less substantial when their particle size increased from 10 to 90 nm at any given concentration. All the nanosilica particles also increased the viscosity of the paste. This increasing effect was higher for smaller-sized nanosilica particles and at higher concentrations.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"19 ","pages":"Article 100128"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152662","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2025-02-12DOI: 10.1016/j.cement.2025.100135
Sarah Danieli , José S. Andrade Neto , Erick Grünhäuser Soares , Thainá Faria Oliveira , Bruna L.F. Brito , Ana Paula Kirchheim
Portland cement is one of the most used materials in the world. Despite the environmental harm its production causes, it will most likely continue dominating the market, given its remarkable characteristics and widespread use worldwide with high consumer acceptance. Improvements in the energy demand, equipment efficiency, and intensification of alternative materials have been proposed to mitigate the large amount of CO2 emissions during the clinker process. However, even if applied, only some extent of the CO2 emitted could be avoided since the most significant portion comes from the limestone decomposition, which cannot be avoided, fitting the cement industry into the list of hard-to-abate industries. In this scenario, new companies are developing and improving indispensable carbon capture technologies and CO2 reapplication in new processes. With the advance of carbon market regulation, the technologies that prove to be the most efficient will have a competitive advantage in this new economy. This study reviews the current carbon capture scenario in cement and concrete production and highlights the leading companies emerging in this sector, exploring the main aspects of their processes, technology readiness levels (TRL), real-world achievements, scalability, suitability for achieving net-zero emissions, credibility, feasibility, opportunities, and limitations.
{"title":"Shaping a sustainable path: Exploring opportunities and challenges in carbon capture and utilization in cement and concrete industry","authors":"Sarah Danieli , José S. Andrade Neto , Erick Grünhäuser Soares , Thainá Faria Oliveira , Bruna L.F. Brito , Ana Paula Kirchheim","doi":"10.1016/j.cement.2025.100135","DOIUrl":"10.1016/j.cement.2025.100135","url":null,"abstract":"<div><div>Portland cement is one of the most used materials in the world. Despite the environmental harm its production causes, it will most likely continue dominating the market, given its remarkable characteristics and widespread use worldwide with high consumer acceptance. Improvements in the energy demand, equipment efficiency, and intensification of alternative materials have been proposed to mitigate the large amount of CO<sub>2</sub> emissions during the clinker process. However, even if applied, only some extent of the CO<sub>2</sub> emitted could be avoided since the most significant portion comes from the limestone decomposition, which cannot be avoided, fitting the cement industry into the list of <em>hard-to-abate</em> industries. In this scenario, new companies are developing and improving indispensable carbon capture technologies and CO<sub>2</sub> reapplication in new processes. With the advance of carbon market regulation, the technologies that prove to be the most efficient will have a competitive advantage in this new economy. This study reviews the current carbon capture scenario in cement and concrete production and highlights the leading companies emerging in this sector, exploring the main aspects of their processes, technology readiness levels (TRL), real-world achievements, scalability, suitability for achieving net-zero emissions, credibility, feasibility, opportunities, and limitations.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"19 ","pages":"Article 100135"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143453395","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2024-12-14DOI: 10.1016/j.cement.2024.100124
S. Pavia , O. Alelweet
To produce calcium aluminate cement (CAC), bauxites are usually fused with lime/limestone at high temperature (1600 °C). At this temperature, the bauxite´s hydrates of alumina break down - dehydroxylation - and combine with calcium forming monocalcium aluminate (CA), the principal active phase in CAC.
A previous study evidenced that the Saudi bauxite begins dehydroxylation at low temperature (300 °C). This paper investigates whether low temperature can produce a cement, to reduce the carbon footprint of cement production. Cements are sintered by fusing the bauxite with calcium sources (limestone and quicklime) at temperatures from 600 to 1200 °C.
The results evidenced that limestone fusion is the most efficient method, as it renders hydraulic phases at 800 °C (C12A7) and 1000 °C (haüyne). The early release of Ca2+ from the limestone acts as a flux, lowering the breakdown point of the bauxite´s components. C12A7 (mayenite) which can speed up hydration and setting, appears widely in the limestone-bauxite cements, beginning at 800 °C and remaining stable up to 1200 °C.
The bauxite´s gypsum released sulphur, affording the sintering of calcium-sulfoaluminate (haüyne) at 1000 °C. Therefore, the bauxite can produce sulfoaluminate cement, a green cement which can reduce carbon emissions and fight climate change.
The bauxite´s high silica content and the breakdown of its kaolinite polymorph nacrite, facilitate the production of hydraulic calcium silicate clinkers (belite, andradite, gehlenite, wollastonite and prehnite) which afford strength on hydration.
The fluxing action of iron, aluminium and sulphur, significant in the bauxite, lowered the clinkering temperature.
{"title":"Potential of Saudi Arabian bauxite to produce low-carbon cement","authors":"S. Pavia , O. Alelweet","doi":"10.1016/j.cement.2024.100124","DOIUrl":"10.1016/j.cement.2024.100124","url":null,"abstract":"<div><div>To produce calcium aluminate cement (CAC), bauxites are usually fused with lime/limestone at high temperature (1600 °C). At this temperature, the bauxite´s hydrates of alumina break down - dehydroxylation - and combine with calcium forming monocalcium aluminate (CA), the principal active phase in CAC.</div><div>A previous study evidenced that the Saudi bauxite begins dehydroxylation at low temperature (300 °C). This paper investigates whether low temperature can produce a cement, to reduce the carbon footprint of cement production. Cements are sintered by fusing the bauxite with calcium sources (limestone and quicklime) at temperatures from 600 to 1200 °C.</div><div>The results evidenced that limestone fusion is the most efficient method, as it renders hydraulic phases at 800 °C (C<sub>12</sub>A<sub>7</sub>) and 1000 °C (haüyne). The early release of Ca<sup>2+</sup> from the limestone acts as a flux, lowering the breakdown point of the bauxite´s components. C<sub>12</sub>A<sub>7</sub> (mayenite) which can speed up hydration and setting, appears widely in the limestone-bauxite cements, beginning at 800 °C and remaining stable up to 1200 °C.</div><div>The bauxite´s gypsum released sulphur, affording the sintering of calcium-sulfoaluminate (haüyne) at 1000 °C. Therefore, the bauxite can produce sulfoaluminate cement, a green cement which can reduce carbon emissions and fight climate change.</div><div>The bauxite´s high silica content and the breakdown of its kaolinite polymorph nacrite, facilitate the production of hydraulic calcium silicate clinkers (belite, andradite, gehlenite, wollastonite and prehnite) which afford strength on hydration.</div><div>The fluxing action of iron, aluminium and sulphur, significant in the bauxite, lowered the clinkering temperature.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"19 ","pages":"Article 100124"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152664","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2025-01-31DOI: 10.1016/j.cement.2025.100133
Ana Bergmann , Leandro F.M. Sanchez
Alkali aggregate reaction (AAR) affected structures show reduced serviceability and premature distress in over 50 countries worldwide. Several laboratory test protocols have been proposed to evaluate the potential reactivity of aggregates by varying the conditions known to trigger and sustain the reaction. Among them, the most popular methods are the accelerated mortar bar test (AMBT) and the concrete prism test (CPT). Nevertheless, exposure site data, displaying the behaviour of concrete blocks exposed to real environmental conditions, has increased considerably recently, showing significant discrepancies between laboratory and concrete field performance. This study explores the reliability of laboratory tests, indicating moderate accuracy in predicting field performance for the AMBT and the CPT. The findings highlight an opportunity for recalibration of these methods through advanced analytical models that account for environmental conditions, alkali content, and the presence of SCMs to improve predictive accuracy. These measures will enhance concrete infrastructure safety by identifying risks associated with incorporating AAR-prone aggregates into new structures.
{"title":"Assessing the reliability of laboratory test procedures for predicting concrete field performance against alkali-aggregate reaction (AAR)","authors":"Ana Bergmann , Leandro F.M. Sanchez","doi":"10.1016/j.cement.2025.100133","DOIUrl":"10.1016/j.cement.2025.100133","url":null,"abstract":"<div><div>Alkali aggregate reaction (AAR) affected structures show reduced serviceability and premature distress in over 50 countries worldwide. Several laboratory test protocols have been proposed to evaluate the potential reactivity of aggregates by varying the conditions known to trigger and sustain the reaction. Among them, the most popular methods are the accelerated mortar bar test (AMBT) and the concrete prism test (CPT). Nevertheless, exposure site data, displaying the behaviour of concrete blocks exposed to real environmental conditions, has increased considerably recently, showing significant discrepancies between laboratory and concrete field performance. This study explores the reliability of laboratory tests, indicating moderate accuracy in predicting field performance for the AMBT and the CPT. The findings highlight an opportunity for recalibration of these methods through advanced analytical models that account for environmental conditions, alkali content, and the presence of SCMs to improve predictive accuracy. These measures will enhance concrete infrastructure safety by identifying risks associated with incorporating AAR-prone aggregates into new structures.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"19 ","pages":"Article 100133"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-03-01Epub Date: 2024-12-19DOI: 10.1016/j.cement.2024.100125
Kenedy Geofrey Fikeni , Xueyu Pang , Yukun Zhao , Shenglai Guo , Jie Ren , Kaihe Lv , Jinsheng Sun
During offshore cementing at shallow depth, the low-temperature environment at the bottom of the sea and the low-density requirement of the cement slurry significantly hinder the strength development of oil well cement systems. Hence there is always a strong need to take various measures to enhance the strength development of low-density oil well cement systems. During this study, potential synergistic effects of silica fume, nanomaterials (C-S-H nano-seeds, nano-silica, nano-alumina), and inorganic salts (CaCl2, NaCl, Na2SiO3) to improve the strength of low-density well cement slurry were investigated. Water-to-cement ratio (w/c) was varied between 1.04 and 1.28 to obtain a constant slurry density of 1.5 g/cm3. Test results revealed that the addition of silica fume altered the rheology and flow behavior of low-density cement slurries, resulting in flat rheology profiles at high shear rates. The Bingham plastic model can describe the rheological behavior of cement slurries without silica fume, whereas the Power-law model is more suitable to cement slurries with silica fume. High-dosage silica fume (30 %) is shown to have similar acceleration capability as the strongest nanomaterial accelerator (i.e. C-S-H nano-seeds) at 2 % dosage. However, adding nanomaterials to silica-fume-enriched slurries cannot further increase the hydration rate of cement (i.e. no synergistic effect), possibly due to their similar acceleration mechanism. In contrast, adding chloride-based inorganic salts to silica-fume-enriched slurries further increased the hydration rate of cement significantly, exhibiting a strong synergistic effect. Based on the 7-day compressive strength test results at 15°C, the addition of silica fume or nanomaterials individually can increase the strength of neat cement by up to 92 %, while the combined addition of silica fume and NaCl can increase its strength by 306 %.
{"title":"Synergistic effects of silica fume, nanomaterials and inorganic salts on the hydration and compressive strength of low-density oil well cement slurry","authors":"Kenedy Geofrey Fikeni , Xueyu Pang , Yukun Zhao , Shenglai Guo , Jie Ren , Kaihe Lv , Jinsheng Sun","doi":"10.1016/j.cement.2024.100125","DOIUrl":"10.1016/j.cement.2024.100125","url":null,"abstract":"<div><div>During offshore cementing at shallow depth, the low-temperature environment at the bottom of the sea and the low-density requirement of the cement slurry significantly hinder the strength development of oil well cement systems. Hence there is always a strong need to take various measures to enhance the strength development of low-density oil well cement systems. During this study, potential synergistic effects of silica fume, nanomaterials (C-S-H nano-seeds, nano-silica, nano-alumina), and inorganic salts (CaCl<sub>2</sub>, NaCl, Na<sub>2</sub>SiO<sub>3</sub>) to improve the strength of low-density well cement slurry were investigated. Water-to-cement ratio (w/c) was varied between 1.04 and 1.28 to obtain a constant slurry density of 1.5 g/cm<sup>3</sup>. Test results revealed that the addition of silica fume altered the rheology and flow behavior of low-density cement slurries, resulting in flat rheology profiles at high shear rates. The Bingham plastic model can describe the rheological behavior of cement slurries without silica fume, whereas the Power-law model is more suitable to cement slurries with silica fume. High-dosage silica fume (30 %) is shown to have similar acceleration capability as the strongest nanomaterial accelerator (i.e. C-S-H nano-seeds) at 2 % dosage. However, adding nanomaterials to silica-fume-enriched slurries cannot further increase the hydration rate of cement (i.e. no synergistic effect), possibly due to their similar acceleration mechanism. In contrast, adding chloride-based inorganic salts to silica-fume-enriched slurries further increased the hydration rate of cement significantly, exhibiting a strong synergistic effect. Based on the 7-day compressive strength test results at 15°C, the addition of silica fume or nanomaterials individually can increase the strength of neat cement by up to 92 %, while the combined addition of silica fume and NaCl can increase its strength by 306 %.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"19 ","pages":"Article 100125"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143152665","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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