CEMENT最新文献

{"title":"Modelling and visualizing the impact of metakaolin on the alkali concentration in cement paste pore solution","authors":"Ana Bergmann ,&nbsp;Klaartje de Weerdt ,&nbsp;Maxime Ranger ,&nbsp;Miriam E. Krüger ,&nbsp;Petter Hemstad ,&nbsp;Barbara Lothenbach","doi":"10.1016/j.cement.2025.100148","DOIUrl":"10.1016/j.cement.2025.100148","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"21 ","pages":"Article 100148"},"PeriodicalIF":0.0,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144306986","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}

{"title":"Cation uptake by fine aggregate in hardened cement mortar and its effect on electrical properties","authors":"Atolo A. Tuinukuafe ,&nbsp;Anuj Parashar ,&nbsp;Xiaoqiang Hou ,&nbsp;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}

{"title":"Moisture dynamics and influence on alkali-silica reaction induced expansion: A comprehensive laboratory study","authors":"O.D. Olajide ,&nbsp;M.R. Nokken ,&nbsp;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}

{"title":"Nanoscale pore structure analysis of cementitious materials subjected to delayed ettringite formation","authors":"M. Shariful Islam ,&nbsp;Yamini Shekar ,&nbsp;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}

{"title":"Thermal, mechanical, and transport properties of C-S-H at the molecular scale: A force field benchmark","authors":"Tulio Honorio,&nbsp;Fatima Masara,&nbsp;Gang Huang,&nbsp;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":"2025-05-12","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}

{"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,&nbsp;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 (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.</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}

{"title":"Phase assemblage and microstructure of burnt oil shale-containing blended cements","authors":"Federica Boscaro ,&nbsp;Diana Londono-Zuluaga ,&nbsp;Peter Kruspan ,&nbsp;Michael Plötze ,&nbsp;Karen Scrivener ,&nbsp;Robert J. Flatt","doi":"10.1016/j.cement.2025.100139","DOIUrl":"10.1016/j.cement.2025.100139","url":null,"abstract":"<div><div>Burnt oil shale (BOS), obtained from the combustion of oil shale, is a promising supplementary cementitious material (SCM) based on its chemistry and mineralogy. This paper summarizes the use of BOS and its hydration in blended cements. It presents new data on the effect of combinations of alkali activators and Ca(NO₃)₂ in blended cements containing 50 % Portland cement (OPC) where BOS is combined with limestone, fly ash and ground granulated blast furnace slag. These chemical admixtures increase the slope of the correlation between compressive strength and heat of hydration of BOS containing mixes, providing an increase in compressive strength from 1 to 7 days for similar heat release to the control system. In contrast, the slope is not affected in absence of BOS. The change is due to a higher volume of hydrates from BOS increased hydration for a given C₃S degree of hydration, likely from a less exothermic dissolution of BOS amorphous component. These admixtures increase the reactivity of both BOS and OPC at different curing times and depending on the type of alkali activator. They promote ettringite and portlandite precipitation, inducing a refinement of the microstructure, particularly around BOS particles. The information presented should pave the way to a broader and more effective use of BOS in blended cements with particularly low clinker contents.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"20 ","pages":"Article 100139"},"PeriodicalIF":0.0,"publicationDate":"2025-04-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829562","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}

{"title":"Stabilization characteristics of cemented lateritic soil produced with selected cement types","authors":"A.A. Amadi ,&nbsp;S.S. Kolo ,&nbsp;A. Yusuf ,&nbsp;F.E. Eze ,&nbsp;U. Salihu","doi":"10.1016/j.cement.2025.100136","DOIUrl":"10.1016/j.cement.2025.100136","url":null,"abstract":"<div><div>It is recognized that different cements have different properties and stabilization effectiveness for different applications. The challenge of using the right type of cement should be a concern for practitioners in civil engineering construction. In this study, an experimental testing programme was conducted to evaluate and compare the stabilizing effects of CEM I 42.5 N, CEM II/B-L 42.5 N and CEM III/A 42.5 N types of cement on some physical and mechanical properties of lateritic soil. Laboratory tests performed on soil mixtures containing the selected cements added to constitute 0, 3, 6, 9 and 12 % of the dry weight of the composite materials include the consistency and compaction tests determined on the basis of fresh mixtures. In addition, unconfined compressive strength (UCS) test on specimens compacted at optimum moisture conditions with the British Standard Light (BSL) compaction effort and cured for 7, 28 and 90 days was performed. In equal proportions, soil mixtures prepared with the different types of cements yielded comparable results in terms of reducing the plasticity index (PI) from values as high as 60 % in untreated state to 5.05 %, 7.05 % and 8.2 % respectively for CEM I, CEM II and CEM III at 12 % cement content. Addition of cement also increased both the maximum dry unit weight (γ_dmax) and optimum moisture content (OMC) of the soil with CEM I cement having the greatest effect while CEM III cement affected the γ_dmax of the soil the least. For example, when compacted with BSH effort, CEM I achieved γ_dmax = 1.95 kN/m³ and OMC = 25 %, while for CEM III, γ_dmax = 1.63 kN/m³ and OMC = 22.6 % compared to γ_dmax of 1.53 kN/m³ and OMC of 21.1 % for the untreated soil. Regardless of the cement type, there was an overall improvement in the strength properties of the lateritic soil represented by a range of 11 – 14 times for UCS and 31 - 62 folds for E₅₀ at 12 % cement after 90 days curing duration in comparison with the untreated soil. While strength gain was higher in CEM I based mixtures at early (7 day) age (1635.44, 1622.85 and 1599.55 kN/m2 for CEM I, CEM II and CEM III respectively at 12 % cement content), CEM III provided superior strength improvement at the long term (90 day) curing period (2566.25 compared to 2444.58 and 2465.77 kN/m² respectively for CEM I and CEM II at 12 % cement content). Using the variance analysis (ANOVA) at a significance level (α) of 0.05, the influence of cement type was statistically confirmed for the liquid limit, optimum moisture content and UCS at 28 and 90 days curing ages.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"19 ","pages":"Article 100136"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143510299","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}

{"title":"Significance of fineness of pozzolans in determining pozzolanic reactivity","authors":"Mahipal Kasaniya,&nbsp;Michael DA Thomas,&nbsp;Ted Moffatt,&nbsp;Ashlee Hossack","doi":"10.1016/j.cement.2025.100137","DOIUrl":"10.1016/j.cement.2025.100137","url":null,"abstract":"<div><div>This paper presents the quantification of the pozzolanic reactivity of pozzolans examined in terms of compressive strength, bound water and electrical resistivity. The pozzolans studied included natural pozzolans, glass pozzolans and fly ash that were ground to four fineness levels or median particle sizes (d₅₀) of approximately 3, 5, 10 and 15 µm. Quantitative X-ray diffraction was employed to determine the amorphous content of pozzolans. The UNB lime-reactivity test and a modified ASTM <span><span>C311</span><svg><path></path></svg></span> activity with portland cement test were performed in mortars. In these two tests, bulk electrical resistivity measurements were conducted before measuring compressive strength. Additionally, pastes were prepared for bound water in accordance with the R³ test or ASTM <span><span>C1897</span><svg><path></path></svg></span>. While the pozzolanic reactivity for all materials tested generally improves with the fineness, one pozzolan could demonstrate a very different rate of pozzolanicity improvements compared to that of others. Bulk electrical resistivity provides a reliable assessment of pozzolanic reactivity and can help differentiate pozzolanic and pozzolanic-hydraulic materials when used in conjunction with compressive strength. The modified ASTM <span><span>C311</span><svg><path></path></svg></span> test is also found to be suitable and effective in rapidly distinguishing pozzolans, especially slow reactive ones, from inert materials at 7 days. A novel amorphous-fineness index derived by combining the amorphous content and fineness of pozzolans to reasonably predict the pozzolanic reactivity and limitations of the index are discussed.</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"19 ","pages":"Article 100137"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526710","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}

{"title":"Influence of metakaolin content on the microstructure and strength in hardened LC3 paste","authors":"Qi Luo ,&nbsp;Xinyu Zhang ,&nbsp;Junchao Yu ,&nbsp;Guoqing Geng","doi":"10.1016/j.cement.2025.100138","DOIUrl":"10.1016/j.cement.2025.100138","url":null,"abstract":"<div><div>This study systematically investigates the impact of varying metakaolin contents on the compressive strength and microstructure of hardened limestone calcined clay cement (LC³) paste. The findings reveal that increasing metakaolin content intensifies the aluminum sulfate reaction peak and accelerates its onset, while decreasing metakaolin leads to higher total calcium hydroxide (Ca(OH)₂) and calcium carbonate (CaCO₃) levels in the system. A specific threshold of 70 % metakaolin content is identified as optimal for pozzolanic activity; excess metakaolin remains unreacted. The addition of metakaolin refines the pore structure, reduces harmful large pores, and promotes the formation of ettringite and other hydration products, enhancing mechanical properties. Notably, a sample with 70 % metakaolin content exhibits higher compressive strength than one with 100 % metakaolin, indicating that metakaolin containing 30 % impurities (referred to as sand powder) demonstrates superior mechanical performance. These results support the development of LC³ as a commercially viable and eco-friendly alternative to Ordinary Portland Cement (OPC).</div></div>","PeriodicalId":100225,"journal":{"name":"CEMENT","volume":"19 ","pages":"Article 100138"},"PeriodicalIF":0.0,"publicationDate":"2025-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143610612","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}