Basalt fiber reactive powder concrete (BFRPC) was prepared by incorporating basalt fibers (BFs) instead of steel fiber into reactive powder concrete (RPC). In this study, we experimentally and numerically analyzed the impact resistance of BFRPC at different strain rates (101∼101 s1). The Φ75mm Split Hopkinson pressure bar (SHPB) was used for impact compression tests and the finite element software LS-DYNA was used for numerical simulation analysis. The results showed that the high strength BFRPC has an obvious strain rate effect and the dynamic growth factor (DIF) of compressive strength increases logarithmically with strain rate. Meanwhile, the parameters of the CEB model were refitted and the relationship between strain rate and DIF was established. By using the Johnson_Holmquist_Concrete material constitutive model (HJC model), the stress-strain curves and failure patterns obtained were consistent with the experimental results. The incorporation of BFs significantly improve the deformation properties of BFRPC.
{"title":"Investigation of dynamic compression properties of basalt fiber reactive powder concrete","authors":"Haiyang Sha, Jinchun Liu, Xianwen Fu","doi":"10.1680/jadcr.23.00007","DOIUrl":"https://doi.org/10.1680/jadcr.23.00007","url":null,"abstract":"Basalt fiber reactive powder concrete (BFRPC) was prepared by incorporating basalt fibers (BFs) instead of steel fiber into reactive powder concrete (RPC). In this study, we experimentally and numerically analyzed the impact resistance of BFRPC at different strain rates (10<sup>1</sup>∼10<sup>1</sup> s<sup>1</sup>). The Φ75mm Split Hopkinson pressure bar (SHPB) was used for impact compression tests and the finite element software LS-DYNA was used for numerical simulation analysis. The results showed that the high strength BFRPC has an obvious strain rate effect and the dynamic growth factor (DIF) of compressive strength increases logarithmically with strain rate. Meanwhile, the parameters of the CEB model were refitted and the relationship between strain rate and DIF was established. By using the Johnson_Holmquist_Concrete material constitutive model (HJC model), the stress-strain curves and failure patterns obtained were consistent with the experimental results. The incorporation of BFs significantly improve the deformation properties of BFRPC.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138509762","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Katharina Schraut, Burkart Adamczyk, Christian Adam, Dietmar Stephan, Birgit Meng, Sebastian Simon, Julia von Werder, Tamino Hirsch, Tanja Manninger
Fused cement clinker can be produced from molten basic oxygen furnace slag (BOFS) via a reductive thermochemical treatment. During the thermochemical treatment, oxidic iron is reduced to metallic iron and separated. The resulting low-iron slag has a chemical and mineralogical composition similar to ordinary Portland cement (OPC) clinker. In this study, the hydraulic reactivity of the fused clinker from BOFS (BOFS) with and without gypsum was investigated using isothermal calorimetry, differential scanning calorimetry (DSC), in-situ X-ray diffraction and powder X-ray diffraction (PXRD). Furthermore, a synthetic fused clinker without foreign ions and fused clinker produced by a mixture of both materials was studied. The hydraulic reaction of the fused clinker from BOFS was considerably slower than that of ordinary Portland cement. However, the reaction can be accelerated by adding gypsum as a sulfate carrier. Furthermore, the results showed an increased reaction rate with decreasing content of foreign ions such as Fe, P or Mn.
{"title":"Effect of gypsum on the hydration of fused cement clinker from basic oxygen furnace slag","authors":"Katharina Schraut, Burkart Adamczyk, Christian Adam, Dietmar Stephan, Birgit Meng, Sebastian Simon, Julia von Werder, Tamino Hirsch, Tanja Manninger","doi":"10.1680/jadcr.23.00070","DOIUrl":"https://doi.org/10.1680/jadcr.23.00070","url":null,"abstract":"Fused cement clinker can be produced from molten basic oxygen furnace slag (BOFS) via a reductive thermochemical treatment. During the thermochemical treatment, oxidic iron is reduced to metallic iron and separated. The resulting low-iron slag has a chemical and mineralogical composition similar to ordinary Portland cement (OPC) clinker. In this study, the hydraulic reactivity of the fused clinker from BOFS (BOFS) with and without gypsum was investigated using isothermal calorimetry, differential scanning calorimetry (DSC), <i>in-situ</i> X-ray diffraction and powder X-ray diffraction (PXRD). Furthermore, a synthetic fused clinker without foreign ions and fused clinker produced by a mixture of both materials was studied. The hydraulic reaction of the fused clinker from BOFS was considerably slower than that of ordinary Portland cement. However, the reaction can be accelerated by adding gypsum as a sulfate carrier. Furthermore, the results showed an increased reaction rate with decreasing content of foreign ions such as Fe, P or Mn.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138509742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Deise Trevizan Pelissaro, Suelen Cristina Vanzetto, Francisco Dalla Rosa, Pedro Domingos Marques Prietto, Adriana Augustin Silveira
Although alkali-activated materials are considered potential substitutes for Portland cement, they still present elevated costs and significant emissions of CO2. One way to partially overcome this disadvantage is the development of alternative activators, such as a sodium silicate based on the dissolution of rice husk ash (RHA). However, to maximize the mechanical performance of alkali-activated materials, the production of RHA-based sodium silicates needs to be fully understood. This article investigates the production process of an alternative RHA-based sodium silicate activator through the experimental evaluation of the following parameters: RHA grinding time, RHA dissolution time, thermal curing temperature and time. The mechanical performance was evaluated through compressive strength tests carried out on alkali-activated pastes made up of metakaolin, as a precursor, and two types of activators (RHA-based sodium silicate and commercial sodium silicate). Microstructural features were evaluated by performing X-Ray Diffraction, Scanning Electron Microscopy, and Thermogravimetry analyses. The optimized production was obtained for a grinding time of 30 minutes, a thermal curing temperature of 40°C, a dissolution time of 6 hours, and a thermal curing time of 8 hours. The results show the efficiency of the alternative alkaline activator, which may represent a technically viable solution for the larger-scale application of alkali-activated materials.
{"title":"Parametric analysis of the production of alternative sodium silicate applied in alkali-activated materials","authors":"Deise Trevizan Pelissaro, Suelen Cristina Vanzetto, Francisco Dalla Rosa, Pedro Domingos Marques Prietto, Adriana Augustin Silveira","doi":"10.1680/jadcr.23.00005","DOIUrl":"https://doi.org/10.1680/jadcr.23.00005","url":null,"abstract":"Although alkali-activated materials are considered potential substitutes for Portland cement, they still present elevated costs and significant emissions of CO<sub>2</sub>. One way to partially overcome this disadvantage is the development of alternative activators, such as a sodium silicate based on the dissolution of rice husk ash (RHA). However, to maximize the mechanical performance of alkali-activated materials, the production of RHA-based sodium silicates needs to be fully understood. This article investigates the production process of an alternative RHA-based sodium silicate activator through the experimental evaluation of the following parameters: RHA grinding time, RHA dissolution time, thermal curing temperature and time. The mechanical performance was evaluated through compressive strength tests carried out on alkali-activated pastes made up of metakaolin, as a precursor, and two types of activators (RHA-based sodium silicate and commercial sodium silicate). Microstructural features were evaluated by performing X-Ray Diffraction, Scanning Electron Microscopy, and Thermogravimetry analyses. The optimized production was obtained for a grinding time of 30 minutes, a thermal curing temperature of 40°C, a dissolution time of 6 hours, and a thermal curing time of 8 hours. The results show the efficiency of the alternative alkaline activator, which may represent a technically viable solution for the larger-scale application of alkali-activated materials.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138509743","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Steel slag (SS) is a by-product of steel industry, and its recycling is of great significance. In this study, the influence of SS fineness and curing regimes on the hydration properties of cement and the effects of SS content on the compressive strength of pastes were investigated. The hydration products and microstructure of pastes were further explored through X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The results show that the compressive strength decreases gradually with the increase of SS, and increases with the increase of the specific surface area of SS. The compressive strength of paste after steam curing is improved, and the compressive strength of the paste mixed with 30% SS can reach more than 50 MPa after 90 days of steam curing. The hydration products of paste mixed with SS is not significantly different from that of cement, which is mainly composed of Ca(OH)2 and C-S-H gel, accompanied by a small amount of CaCO3. SS has secondary hydration in long-term age and can fill and refine the pore structure, according to SEM. Using SS as supplementary material is beneficial to reducing cement cost and lowering CO2 emission.
{"title":"Hydration properties of the composite cementitious materials containing steel slag under steam curing condition","authors":"Maosen Li, Xiao Liang, Long Chen, Shuhua Liu","doi":"10.1680/jadcr.23.00102","DOIUrl":"https://doi.org/10.1680/jadcr.23.00102","url":null,"abstract":"Steel slag (SS) is a by-product of steel industry, and its recycling is of great significance. In this study, the influence of SS fineness and curing regimes on the hydration properties of cement and the effects of SS content on the compressive strength of pastes were investigated. The hydration products and microstructure of pastes were further explored through X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The results show that the compressive strength decreases gradually with the increase of SS, and increases with the increase of the specific surface area of SS. The compressive strength of paste after steam curing is improved, and the compressive strength of the paste mixed with 30% SS can reach more than 50 MPa after 90 days of steam curing. The hydration products of paste mixed with SS is not significantly different from that of cement, which is mainly composed of Ca(OH)<sub>2</sub> and C-S-H gel, accompanied by a small amount of CaCO<sub>3</sub>. SS has secondary hydration in long-term age and can fill and refine the pore structure, according to SEM. Using SS as supplementary material is beneficial to reducing cement cost and lowering CO<sub>2</sub> emission.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138509741","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Andrea Romero-Espinosa, Susana G. Sanfélix, Alejandro Morales-Cantero, Ana Cuesta, Anna-Lena Kjøniksen, Miguel A. G. Aranda, Angeles G. De la Torre, Isabel Santacruz
On the one hand, calcium sulfoaluminate (CSA) eco-cements release about 40% less carbon dioxide (CO 2 ) than Portland cement during fabrication; on the other hand, phase change materials dispersed in a cementitious matrix can help to optimise the indoor temperature of buildings, reducing carbon dioxide emissions related to heating/air conditioning. However, this is only economically viable if it is used as a thin layer (a coating). In addition, the combination of both materials supposes a double environmental benefit. Consequently, the main objective of this work is the preparation of a suitable homogeneous and well-adhered bilayer sample, composed of CSA and CSA-MPCM. To achieve this, in the first step, the effect of pH, temperature and stirring was studied for microencapsulated phase change material (MPCM) aqueous suspensions (47.3 wt%); second, the MPCM (45 wt% with respect to dry cement) was dispersed in a CSA paste; then, in a third step, a homogeneous well-adhered coating of CSA-MPCM, with undamaged MPCM, was obtained on a CSA matrix. This was achieved through rheological measurements and checked by microscopy. Finally, the corresponding CSA and CSA-MPCM mortars were characterised through their mechanical properties (compression) (70 and 13 MPa at 7 days, respectively) and thermal conductivity (2.06 and 1.19 W/mK, respectively).
{"title":"Processing of calcium sulfoaluminate eco-cement coatings containing microencapsulated phase change materials","authors":"Andrea Romero-Espinosa, Susana G. Sanfélix, Alejandro Morales-Cantero, Ana Cuesta, Anna-Lena Kjøniksen, Miguel A. G. Aranda, Angeles G. De la Torre, Isabel Santacruz","doi":"10.1680/jadcr.23.00077","DOIUrl":"https://doi.org/10.1680/jadcr.23.00077","url":null,"abstract":"On the one hand, calcium sulfoaluminate (CSA) eco-cements release about 40% less carbon dioxide (CO 2 ) than Portland cement during fabrication; on the other hand, phase change materials dispersed in a cementitious matrix can help to optimise the indoor temperature of buildings, reducing carbon dioxide emissions related to heating/air conditioning. However, this is only economically viable if it is used as a thin layer (a coating). In addition, the combination of both materials supposes a double environmental benefit. Consequently, the main objective of this work is the preparation of a suitable homogeneous and well-adhered bilayer sample, composed of CSA and CSA-MPCM. To achieve this, in the first step, the effect of pH, temperature and stirring was studied for microencapsulated phase change material (MPCM) aqueous suspensions (47.3 wt%); second, the MPCM (45 wt% with respect to dry cement) was dispersed in a CSA paste; then, in a third step, a homogeneous well-adhered coating of CSA-MPCM, with undamaged MPCM, was obtained on a CSA matrix. This was achieved through rheological measurements and checked by microscopy. Finally, the corresponding CSA and CSA-MPCM mortars were characterised through their mechanical properties (compression) (70 and 13 MPa at 7 days, respectively) and thermal conductivity (2.06 and 1.19 W/mK, respectively).","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135041589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Behçet Dündar, Emriye Çinar Resuloğlulari, Turhan Can Karci
Reinforced concrete (RC) is one of the most widely used building materials. However, RC, especially in coastal seaside or humid environments, can suffer reinforcement corrosion with the result that the reinforcement fails to perform its function over time. The effect of a retarder additive used to eliminate loss of consistency in hot, windy and humid weather on the corrosion of RC elements was investigated in this work. Four different concrete types were assessed, with 0%, 1%, 1.5% and 2% additions of the chemical additive. Along with accelerated corrosion and pressure tests, physical properties such as electrical resistivity, water absorption, porosity, unit weight and capillary water absorption were also determined. The results of this work indicate that the use of up to 2% of the setting retarder did not pose a problem in terms of the physical and mechanical properties of the concrete. However, in terms of the frequently encountered corrosion problem, the use of 1.5% is more appropriate. Many chemical additives are used for different purposes in concrete and it is suggested that, alongside physical and mechanical properties, durability characteristics should also be examined when determining the suitable ratios of these additives.
{"title":"Effect of use of retardant chemical additives in concrete on rebar corrosion","authors":"Behçet Dündar, Emriye Çinar Resuloğlulari, Turhan Can Karci","doi":"10.1680/jadcr.22.00189","DOIUrl":"https://doi.org/10.1680/jadcr.22.00189","url":null,"abstract":"Reinforced concrete (RC) is one of the most widely used building materials. However, RC, especially in coastal seaside or humid environments, can suffer reinforcement corrosion with the result that the reinforcement fails to perform its function over time. The effect of a retarder additive used to eliminate loss of consistency in hot, windy and humid weather on the corrosion of RC elements was investigated in this work. Four different concrete types were assessed, with 0%, 1%, 1.5% and 2% additions of the chemical additive. Along with accelerated corrosion and pressure tests, physical properties such as electrical resistivity, water absorption, porosity, unit weight and capillary water absorption were also determined. The results of this work indicate that the use of up to 2% of the setting retarder did not pose a problem in terms of the physical and mechanical properties of the concrete. However, in terms of the frequently encountered corrosion problem, the use of 1.5% is more appropriate. Many chemical additives are used for different purposes in concrete and it is suggested that, alongside physical and mechanical properties, durability characteristics should also be examined when determining the suitable ratios of these additives.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135041590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Yan He, Chunyang You, Shuhua Liu, Mingjing Jiang, Pengcheng Shi
In order to enhance the utilization efficiency of lithium slag (LS) in cement-based materials, calcificated and thermal activation of LS were conducted, and the activation mechanism have been analyzed. Results showed that gypsum and spodumene in LS decomposed at high temperature via calcificated and thermal activation, and spodumene as well as limestone calcination decomposed at high temperature, to generate more CS, CA and other mineral phases. Calcificated and thermal activation could enhance the activity of LS to participate in pozzolanic reaction, and generate the formation of more hydration products. After calcificated and thermal activation of LS, the hydration exothermic peak, the total amount of hydration heat, and hydration production of LS composite binder were significantly increased. The hardened matrix was more compact with less porosity. Compared with cement mortar incorporated with raw LS, the incorporation of calcificated and thermal activated LS enhanced the compressive strength of cement mortar at 3d, 7d, and 28d by 25.8%, 13.4%, and 20.5%, respectively.
{"title":"Effects of thermal activation on the hydration performance of lithium slag-cement composite binder","authors":"Yan He, Chunyang You, Shuhua Liu, Mingjing Jiang, Pengcheng Shi","doi":"10.1680/jadcr.23.00068","DOIUrl":"https://doi.org/10.1680/jadcr.23.00068","url":null,"abstract":"In order to enhance the utilization efficiency of lithium slag (LS) in cement-based materials, calcificated and thermal activation of LS were conducted, and the activation mechanism have been analyzed. Results showed that gypsum and spodumene in LS decomposed at high temperature via calcificated and thermal activation, and spodumene as well as limestone calcination decomposed at high temperature, to generate more CS, CA and other mineral phases. Calcificated and thermal activation could enhance the activity of LS to participate in pozzolanic reaction, and generate the formation of more hydration products. After calcificated and thermal activation of LS, the hydration exothermic peak, the total amount of hydration heat, and hydration production of LS composite binder were significantly increased. The hardened matrix was more compact with less porosity. Compared with cement mortar incorporated with raw LS, the incorporation of calcificated and thermal activated LS enhanced the compressive strength of cement mortar at 3d, 7d, and 28d by 25.8%, 13.4%, and 20.5%, respectively.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135186732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This experimental study investigated the performance of self-compacting concrete (SCC) mixes with magnesia (MgO) waste. In the series produced with a water/binder ratio of 0.40, cement was replaced by magnesia waste at 2%, 4% and 10% by weight in the SCC. Le Chatelier test, slump flow, compressive strength, flexural strength, depth of penetration of water under pressure, ultrasonic pulse velocity and water absorption by capillary testing was conducted to assess sample performance. X-ray diffraction, thermogravimetric analysis, mercury intrusion porosimetry, differential thermal analysis and scanning electron microscopy were used for the microstructural analysis and quantification of phases within each sample. The results indicated that concrete with magnesia waste contains magnesium silicate hydrate (M–S–H) and brucite ((Mg(OH) 2 ) products. Brucite causes strength loss in concrete. Up to 90 days, specimens with magnesia showed increasing compressive and flexural strength. As the amount of magnesia waste increased, the porosity, depth of water penetration under pressure and water absorption by capillary increased. Incorporating more than 10% of magnesia waste in the SCC mixtures resulted in declining strength. The addition of magnesia waste enhanced the expansion of SCC. An optimum dosage (2%) of magnesia waste was the most advantageous to the strength of SCC.
{"title":"Effects of waste magnesia powder as partial cement replacement on self-compacting concrete","authors":"Songül Can, Ali Sariisik, Tayfun Uygunoğlu","doi":"10.1680/jadcr.22.00126","DOIUrl":"https://doi.org/10.1680/jadcr.22.00126","url":null,"abstract":"This experimental study investigated the performance of self-compacting concrete (SCC) mixes with magnesia (MgO) waste. In the series produced with a water/binder ratio of 0.40, cement was replaced by magnesia waste at 2%, 4% and 10% by weight in the SCC. Le Chatelier test, slump flow, compressive strength, flexural strength, depth of penetration of water under pressure, ultrasonic pulse velocity and water absorption by capillary testing was conducted to assess sample performance. X-ray diffraction, thermogravimetric analysis, mercury intrusion porosimetry, differential thermal analysis and scanning electron microscopy were used for the microstructural analysis and quantification of phases within each sample. The results indicated that concrete with magnesia waste contains magnesium silicate hydrate (M–S–H) and brucite ((Mg(OH) 2 ) products. Brucite causes strength loss in concrete. Up to 90 days, specimens with magnesia showed increasing compressive and flexural strength. As the amount of magnesia waste increased, the porosity, depth of water penetration under pressure and water absorption by capillary increased. Incorporating more than 10% of magnesia waste in the SCC mixtures resulted in declining strength. The addition of magnesia waste enhanced the expansion of SCC. An optimum dosage (2%) of magnesia waste was the most advantageous to the strength of SCC.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135293675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In the context of green and low-carbon materials development, the influence of replacing cement with circulating fluidised bed fly ash (CFBFA) on the expansion properties of paste under different curing conditions was first systematically investigated. Then, self-compacting concretes (SCCs) with recycled aggregate (RA) and CFBFA were prepared for filling steel tubes. The experimental results showed that, because of its unique physicochemical properties, the incorporation of CFBFA significantly increased the water requirement needed to achieve standard consistency of the paste and the pore structure was optimised by a reduction in the number of large pores due to the formation of more expansion components (ettringite, gypsum and portlandite are the main expansive products of CFBFA–cement paste). The influence of factors such as curing condition, age and CFBFA on the expansion effect was notable. With a 40% CFBFA content, the RA SCC in the steel tube showed an expansion of 41 μm/m, while the 28-day compressive strength reached 48.9 MPa.
{"title":"Expansion properties of concrete-filled steel tubes with circulating fluidized bed fly ash","authors":"Ruizhen Yan, Guoju Ke, Dongxiao Han","doi":"10.1680/jadcr.23.00088","DOIUrl":"https://doi.org/10.1680/jadcr.23.00088","url":null,"abstract":"In the context of green and low-carbon materials development, the influence of replacing cement with circulating fluidised bed fly ash (CFBFA) on the expansion properties of paste under different curing conditions was first systematically investigated. Then, self-compacting concretes (SCCs) with recycled aggregate (RA) and CFBFA were prepared for filling steel tubes. The experimental results showed that, because of its unique physicochemical properties, the incorporation of CFBFA significantly increased the water requirement needed to achieve standard consistency of the paste and the pore structure was optimised by a reduction in the number of large pores due to the formation of more expansion components (ettringite, gypsum and portlandite are the main expansive products of CFBFA–cement paste). The influence of factors such as curing condition, age and CFBFA on the expansion effect was notable. With a 40% CFBFA content, the RA SCC in the steel tube showed an expansion of 41 μm/m, while the 28-day compressive strength reached 48.9 MPa.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135945126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Taha M. Jassam, Bonnie Lau, Jason Ng Yang-Zhi, Kow Kien-Woh, Ramez A. Al-Mansob, Bariş Erdil, Wenjie Luo
In this study, the effect on the compressive strength of cement with the addition of 1-5 wt% nano-magnetite particles (nano-Fe 3 O 4 ) has been identified at the age of 7 days and 28 days curing. In addition, an approach of aligning these nano-magnetite particles within cement using an external magnetic field was presented, where the orientation of nano-magnetite particles was aligned parallel to the compressive load. The effect of the compressive strength on cement mortar with the aligned nano-magnetite particles has also been compared with the non-aligned samples. Both aligned and non-aligned samples showed positive effects on the compressive strengths as compared to the control samples, where the cement mortar with aligned nano-magnetite showed significant improvement on compressive strength up to 21%. This study also showed that the addition of 3 wt% nano-magnetite particles into cement mortar was the optimal amount to achieve maximum enhancement of compressive strengths.
{"title":"Characterization of cement loaded with magnetically aligned nano-magnetite","authors":"Taha M. Jassam, Bonnie Lau, Jason Ng Yang-Zhi, Kow Kien-Woh, Ramez A. Al-Mansob, Bariş Erdil, Wenjie Luo","doi":"10.1680/jadcr.22.00193","DOIUrl":"https://doi.org/10.1680/jadcr.22.00193","url":null,"abstract":"In this study, the effect on the compressive strength of cement with the addition of 1-5 wt% nano-magnetite particles (nano-Fe 3 O 4 ) has been identified at the age of 7 days and 28 days curing. In addition, an approach of aligning these nano-magnetite particles within cement using an external magnetic field was presented, where the orientation of nano-magnetite particles was aligned parallel to the compressive load. The effect of the compressive strength on cement mortar with the aligned nano-magnetite particles has also been compared with the non-aligned samples. Both aligned and non-aligned samples showed positive effects on the compressive strengths as compared to the control samples, where the cement mortar with aligned nano-magnetite showed significant improvement on compressive strength up to 21%. This study also showed that the addition of 3 wt% nano-magnetite particles into cement mortar was the optimal amount to achieve maximum enhancement of compressive strengths.","PeriodicalId":7299,"journal":{"name":"Advances in Cement Research","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2023-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136113421","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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