Cement and Concrete Research最新文献

{"title":"Effect of silica fume on rheology of slag-fly ash-silica fume-based geopolymer pastes with different activators","authors":"Yiwei Liu ,&nbsp;Cuifang Lu ,&nbsp;Xiang Hu ,&nbsp;Caijun Shi","doi":"10.1016/j.cemconres.2023.107336","DOIUrl":"10.1016/j.cemconres.2023.107336","url":null,"abstract":"<div><p><span><span>This study examined the effect of silica fume contents on the </span>rheological behavior<span><span><span> of slag-fly ash-silica fume-based geopolymer pastes by packing density measurement, low-field NMR, </span>zeta potential<span>, dynamic light scattering and FTIR<span> analyses. Incorporating silica fume<span> into sodium<span> hydroxide (SH)-activated geopolymer pastes<span> resulted in the decrease of packing density and the increases of yield stress, plastic viscosity and </span></span></span></span></span></span>hysteresis loop curve area. The contrary results were found in the pastes activated by sodium silicate (SS). The water states of geopolymer pastes were influenced by SiO</span></span>₂/Na₂O ratio of activator and silica fume dosage. The mobile water content in the sample increased as the silica fume dosage increased, regardless of the SiO₂/Na₂<span>O ratio of activator. The particle size of the silica species in the activator and interstitial<span> fluids is close to that of silica fume. The incorporation of silica fume resulted in the variation in the silicate structural characteristics of the interstitial fluids. The influence of silica fume on the rheological behaviors of geopolymer systems is strongly governed by the interparticle repulsion or attractiveness<span> and activator nature, opposed to the filler effect and dissolution of silica fume. In SS-activated systems, the repulsion between the silanol groups on the silica fume surface and silicate species adsorbed on the surface of precursors particles contributed to the particle separations, thereby enhancing rheological behaviors. In SH-activated system, the attractiveness between divalent metal cations and silanol groups on the surfaces of precursor and silica fume particles was increased and the particle space was restrained. This study would provide new insights into the role of silica fume in the particle interaction of fresh ultra-high performance geopolymer concrete.</span></span></span></p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"174 ","pages":"Article 107336"},"PeriodicalIF":11.4,"publicationDate":"2023-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49698351","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Internal alkali transport in recycling concrete and its impact on alkali-silica reaction","authors":"Andreas Leemann ,&nbsp;Leandro Sanchez","doi":"10.1016/j.cemconres.2023.107334","DOIUrl":"10.1016/j.cemconres.2023.107334","url":null,"abstract":"<div><p>Recycling concrete (RC) produced with recycled aggregates (RA) obtained from demolished concrete structures bears the risk of an alkali-silica reaction (ASR). In this study, the interplay between aggregate reactivity and alkalis contributed by the cement and the RA is investigated. Three sets of concrete mixtures are produced using RA and natural aggregates, both reactive and non-reactive ones. Caesium either present in the RA or in the mixing water of the RC is used to trace the transport of alkalis and their incorporation in ASR products. The result shows that alkali released by RA can intensify ASR. On the other hand, ASR in RA with a low alkali content but reactive aggregate particles can be triggered by the alkali provided by the new cement paste of the RC. The highest risk of ASR in RC is caused by RA from a source concrete already affected by ASR.</p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"174 ","pages":"Article 107334"},"PeriodicalIF":11.4,"publicationDate":"2023-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S000888462300248X/pdfft?md5=8b13d645bb3601c61742793bc28f9b9e&pid=1-s2.0-S000888462300248X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49698446","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Memorial: Dr. Della M. Roy","authors":"R. Doug Hooton ,&nbsp;Karen Scrivener","doi":"10.1016/j.cemconres.2023.107328","DOIUrl":"10.1016/j.cemconres.2023.107328","url":null,"abstract":"","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"174 ","pages":"Article 107328"},"PeriodicalIF":11.4,"publicationDate":"2023-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0008884623002429/pdfft?md5=ebd65d74f0d874c86723973fab3e66f4&pid=1-s2.0-S0008884623002429-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49698491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Role of the structure of synthetic Al(OH)3 on the properties of sulfoaluminate cement-based materials","authors":"Haiyan Li ,&nbsp;Yang Liu ,&nbsp;Jiang Lu ,&nbsp;Wei Zhao ,&nbsp;Muhammad Moeen ,&nbsp;Xuemao Guan ,&nbsp;Jianping Zhu","doi":"10.1016/j.cemconres.2023.107330","DOIUrl":"10.1016/j.cemconres.2023.107330","url":null,"abstract":"<div><p><span><span><span>A promising approach to accelerate cement hydration<span> has been discovered, wherein superfine particles are utilized to introduce additional nucleation sites for the growth of </span></span>hydration products. This study investigated the effects of synthetic </span>amorphous<span> aluminum hydroxide (AH</span></span>₃<span>), bayerite, and boehmite on SCGM properties.</span></p><p>The results show that amorphous AH₃<span> acted as nucleation sites for the growth of bayerite and ettringite (AFt), bayerite provided nucleation sites for the growth of monosulfate (AFm) and AFt, and boehmite could offer nucleation sites for the growth of AFt. Additionally, synthetic AH</span>₃ at pH 12.5 releases AlO₂⁻, and the amount of AlO₂⁻ released and the additional generated AFt were the largest for amorphous AH₃<span>, followed by bayerite and boehmite. Owing to the synergistic effect of the crystal nuclei and AlO</span>₂⁻ released from AH₃, synthetic AH₃<span><span> can promote cement hydration, alter the pore structure of the hardened paste, and improve </span>compressive strength at all ages.</span></p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"174 ","pages":"Article 107330"},"PeriodicalIF":11.4,"publicationDate":"2023-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50164383","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Influence of multi-scale three-dimensional pore characteristics on the mechanical properties of graphene oxide and carbon nanotube incorporated cement paste","authors":"Heongwon Suh,&nbsp;Seongmin Cho,&nbsp;Sungwun Her,&nbsp;Sungchul Bae","doi":"10.1016/j.cemconres.2023.107326","DOIUrl":"10.1016/j.cemconres.2023.107326","url":null,"abstract":"<div><p>The correlation between the three-dimensional pore characteristics and mechanical properties<span> of graphene oxide<span><span> (GO)-and carbon nanotube (CNT)-incorporated cement pastes were investigated. The nano and micro-scale pore characteristics were evaluated by analyzing </span>pore shapes<span><span> and spatial distribution properties using a radial distribution function<span> (RDF). As a result of the nucleation sites effect, blade-like and plate-like pores were primarily formed in the GO-incorporated samples and rod-like pores in the CNT-incorporated samples, as compared to the plain samples without </span></span>nanomaterials. In addition, the pore scattering, instead of the pore clustering property, was improved in the nanomaterial-incorporated samples. Notably, results obtained from X-ray nanoimaging and micro-CT analyses revealed a strong positive linear correlation between the strengths (compressive and splitting tensile strengths) of the composites and the degree of pore scattering.</span></span></span></p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"174 ","pages":"Article 107326"},"PeriodicalIF":11.4,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50164382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Hygrothermal and strength properties of cement mortars containing cenospheres","authors":"Jarosław Strzałkowski,&nbsp;Agata Stolarska,&nbsp;Dominik Kożuch,&nbsp;Joanna Dmitruk","doi":"10.1016/j.cemconres.2023.107325","DOIUrl":"10.1016/j.cemconres.2023.107325","url":null,"abstract":"<div><p>This study characterizes the hygrothermal and microstructural properties of cement composites containing aluminosilicate cenospheres. It involved the preparation of six mortar mixtures based on CEM I 42.5R cement, in which cenospheres accounted for 0 to 100 % of the aggregate content. The research included measurements of thermal properties, compressive and bending strength tests, density tests on the cured mortars, determination of pore distribution and total porosity, and qualitative assessment of the cenosphere-cement matrix contact zone. However, the main emphasis was on moisture-related parameters. The publication discusses the effect of using cenospheres as a substitute for natural sand on water absorption, capillary absorption, and the sorption and desorption of water by the tested composites, along with the influence of individual microstructural properties on moisture properties. The results showed that increasing the amount of cenospheres added as a sand substitute contributed to an increase in the water absorption of the composite and in parallel reduction in the capillary rise coefficient. The increase in the content of cenospheres caused also a clear increase in the sorption capacity of mortars. Moreover as the statistically average distances between the pores decreased, the thermal conductivity of the composites also decreased. Both when considering the porosity and the spacing factor, the conductivity decrease with wet composites was faster than with dry ones. With decreasing distances between the pores, the compressive strength also decreased significantly. Higher content of cenospheres also reduced the density of the composite and at the same time, increased the specific surface area, which contributed to the reduction in the capillary absorption coefficient and the increase in the durability of the entire composite. In addition, relatively good insulating properties of these composites (<em>λ</em> as low as 0.25 W/mK) in comparison to ordinary cement-based mortars make them interesting alternative to traditional solutions, while the appropriate mechanical strength (compressive strength in the range of 37.68 to 17.74 MPa) makes them suitable even for use as structural elements.</p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"174 ","pages":"Article 107325"},"PeriodicalIF":11.4,"publicationDate":"2023-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0008884623002399/pdfft?md5=77bedce4b58d0bf4da323e649e725fd7&pid=1-s2.0-S0008884623002399-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50164381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modifications to reaction mechanisms, phase assemblages and mechanical properties of alkali-activated slags induced by gypsum addition","authors":"Abdelrahman Hamdan,&nbsp;Haemin Song,&nbsp;Zuobang Yao,&nbsp;Mohammed Fouad Alnahhal,&nbsp;Taehwan Kim,&nbsp;Ailar Hajimohammadi","doi":"10.1016/j.cemconres.2023.107311","DOIUrl":"10.1016/j.cemconres.2023.107311","url":null,"abstract":"<div><p>Alkali-activated slags (AASs) are often reported to exhibit fast settings, undermining their utilisation as sustainable binders from a technological point of view. Although gypsum was shown in previous studies to change the setting time of AASs, understanding the mechanism behind the changes in the reactivity and microstructure of the AASs in the presence of gypsum remains unclear which limits its utilisation in AASs. For the activator conditions used in this research (i.e., Na₂O/raw material = 4.5 % and SiO₂/Na₂O = 1.0), gypsum was observed to dissolve quickly in the system, promoting the precipitation of portlandite and thenardite phases which led to a reduction in the pH of the pore solution causing a slow dissolution of slags. Furthermore, gypsum addition increased the setting time and delayed the compressive strength development of the paste, accompanied by a reduction in the total measured heat. The description of the changes in phase assemblages and kinetic of the system provided here is fundamental for predicting the behaviour of gypsum in AASs and promoting the industrial wide-uptake of AAS technology.</p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"174 ","pages":"Article 107311"},"PeriodicalIF":11.4,"publicationDate":"2023-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0008884623002259/pdfft?md5=6fce591f25d939f0b2bd18bd490e478a&pid=1-s2.0-S0008884623002259-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48051583","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low clinker systems - Towards a rational use of SCMs for optimal performance","authors":"Mohsen Ben Haha ,&nbsp;Pipat Termkhajornkit ,&nbsp;Alexandre Ouzia ,&nbsp;Siva Uppalapati ,&nbsp;Bruno Huet","doi":"10.1016/j.cemconres.2023.107312","DOIUrl":"10.1016/j.cemconres.2023.107312","url":null,"abstract":"<div><p><span><span>Progress in understanding the use of SCMs in blended Portland cement and related effects is reviewed. An optimized use of </span>cement components<span><span> will avoid wasting unreacted particles that do not contribute to the mechanical and durability performances. The reactivity of cement components increases with fineness and by controlled production processes. Clinker may become a minor component in the cementitious mix<span> due to the optimized particle packing of blended cements<span>. An optimized mineralogy of the clinker coupled to the addition of activators can help to further reduce its use in composite cements while maintaining concrete performance. Other </span></span></span>cement constituents<span> introduce different filler and chemical effects to the overall reaction and contributes differently to the performance. Filler and chemical effects influence the hydrates assemblage and in particular C-S-H formation, morphology, and chemical composition. The cement and concrete properties at different ages are tightly linked to these properties. Future approaches could be more technical than simply grinding and blending, allowing a better use of each cement component to achieve a lower CO</span></span></span>₂ intensity.</p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"174 ","pages":"Article 107312"},"PeriodicalIF":11.4,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41341908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A 3D stochastic damage model for concrete under monotonic and cyclic loadings","authors":"Yanpeng Wang","doi":"10.1016/j.cemconres.2023.107208","DOIUrl":"10.1016/j.cemconres.2023.107208","url":null,"abstract":"<div><p>A stochastic damage model previously proposed by the author and Li for concrete under monotonic and cyclic loadings is extended to 3D stress states. Specifically, a novel expression form of damage energy release rate<span>, which is the damage driving force thermodynamically, is initiated, and some basic concepts related to concrete damage evolution are further demonstrated. Careful validation of the model against existing experiments reveals that the model is able to well capture the rate effect of concrete and to realistically simulate the monotonic strength<span>, cyclic life, and their accompanying randomness for a wide range of stress states from uniaxial tension to confined compression.</span></span></p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"171 ","pages":"Article 107208"},"PeriodicalIF":11.4,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43757670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Strain-rate sensitivity of cement composites: Insights from field's metal nano-inclusions","authors":"Navid Tourani,&nbsp;Kwesi Sagoe-Crentsil,&nbsp;Wenhui Duan","doi":"10.1016/j.cemconres.2023.107210","DOIUrl":"10.1016/j.cemconres.2023.107210","url":null,"abstract":"<div><p>In this study, we investigated the effects of Field's metal (FM) nanoparticles (NPs) on the mechanical behaviour of cement paste under quasi-static (QS) and dynamic strain rates. We found the highest mechanical improvement under QS loading with 1 % FM dosage, beyond which boosting the dosage diminished its contribution to the mechanical performance. Conversely, under dynamic loadings, boosting the dosage from 1 % to 4 % FM significantly and progressively enhanced the overall mechanical performance. These results indicated that the mechanical impacts that ensue from the microstructural modification effects of FM differ with dosage and strain rates. Under QS loading, the pore-refining effect of the NPs was predominant, whereas, under dynamic loadings, the reinforcing effect of the NPs was the primary factor. Furthermore, by comparing the effects of FM and nanosilica NPs, our findings underscored the pronounced effect of the nanomaterial physical and mechanical properties on the strain-rate sensitivity of cementitious nanocomposites.</p></div>","PeriodicalId":266,"journal":{"name":"Cement and Concrete Research","volume":"171 ","pages":"Article 107210"},"PeriodicalIF":11.4,"publicationDate":"2023-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0008884623001242/pdfft?md5=1aae457972723d1b6d2c9f32570f2aee&pid=1-s2.0-S0008884623001242-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43316002","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}