A. Savić, Sanja Martinović, M. Vlahović, T. Volkov-Husović
Self-compacting concrete (SCC) contains fine mineral fillers such as limestone powder. The idea of this study was to partially replace limestone with waste sulfur since it is hydrophobic, insoluble in water and therefore chemically inert and to compare the properties of produced concrete samples. Fresh concrete properties included: slump-flow, t500, V-funnel time, L-box ratio, segregation ratio, density, and entrained air content. Hardened concrete was tested for compressive, flexural and bond strengths, ultrasonic velocity, dynamic elasticity modulus, dynamic Poisson’s ratio, and microstructure. Flowability and segregation increased, while bulk density, compressive and flexural strength, dynamic elasticity modulus and ultrasonic velocity slight declined. Times t500 and V-funnel time, L-box ratio and entrained air changed insignificantly. Considering that all properties should remain or improve in case of waste valorization and the criteria should set to satisfy requirements for SCC, this study proved that all mixtures can be used for structural applications.
{"title":"Effects of waste sulfur content on properties of self-compacting concrete","authors":"A. Savić, Sanja Martinović, M. Vlahović, T. Volkov-Husović","doi":"10.3989/mc.2020.06919","DOIUrl":"https://doi.org/10.3989/mc.2020.06919","url":null,"abstract":"Self-compacting concrete (SCC) contains fine mineral fillers such as limestone powder. The idea of this study was to partially replace limestone with waste sulfur since it is hydrophobic, insoluble in water and therefore chemically inert and to compare the properties of produced concrete samples. Fresh concrete properties included: slump-flow, t500, V-funnel time, L-box ratio, segregation ratio, density, and entrained air content. Hardened concrete was tested for compressive, flexural and bond strengths, ultrasonic velocity, dynamic elasticity modulus, dynamic Poisson’s ratio, and microstructure. Flowability and segregation increased, while bulk density, compressive and flexural strength, dynamic elasticity modulus and ultrasonic velocity slight declined. Times t500 and V-funnel time, L-box ratio and entrained air changed insignificantly. Considering that all properties should remain or improve in case of waste valorization and the criteria should set to satisfy requirements for SCC, this study proved that all mixtures can be used for structural applications.","PeriodicalId":51113,"journal":{"name":"Materiales de Construccion","volume":"70 1","pages":"216"},"PeriodicalIF":2.1,"publicationDate":"2020-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70316358","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 study proposes a method to convert non-structural calcium-rich construction and demolition waste fines into adsorbents of heavy metal ions by mixing waste fines with diammonium hydrogen phosphate solution to produce hydroxyapatite, which has high surface areas and excellent ion-exchange capacity with heavy metal ions. As a result, environmental polluting waste is converted into environmentally cleaning material. Waste putty powders was chosen as the representative waste to investigate the detailed formation process of hydroxyapatite and the key reaction parameters of the reaction. Results showed that hydroxyapatite can be produced on waste putty particles. Higher ageing temperatures or longer ageing duration are beneficial to the yield and crystallinity of the produced hydroxyapatite. Adsorption testing confirmed that Ni2+ can replace Ca2+ in the hydroxyapatite lattice, leading to the formation of a new crystal, arupite (Ni3(PO4)2•8H2O), and contributing to a modest adsorption capacity for Ni2+ (15 mg/g) for the hydroxyapatite-containing waste putty.
{"title":"Preliminary study on the upcycle of non-structural construction and demolition waste for waste cleaning","authors":"P. Chen, X. Chen, Y. Wang, P. Wang","doi":"10.3989/mc.2020.13819","DOIUrl":"https://doi.org/10.3989/mc.2020.13819","url":null,"abstract":"This study proposes a method to convert non-structural calcium-rich construction and demolition waste fines into adsorbents of heavy metal ions by mixing waste fines with diammonium hydrogen phosphate solution to produce hydroxyapatite, which has high surface areas and excellent ion-exchange capacity with heavy metal ions. As a result, environmental polluting waste is converted into environmentally cleaning material. Waste putty powders was chosen as the representative waste to investigate the detailed formation process of hydroxyapatite and the key reaction parameters of the reaction. Results showed that hydroxyapatite can be produced on waste putty particles. Higher ageing temperatures or longer ageing duration are beneficial to the yield and crystallinity of the produced hydroxyapatite. Adsorption testing confirmed that Ni2+ can replace Ca2+ in the hydroxyapatite lattice, leading to the formation of a new crystal, arupite (Ni3(PO4)2•8H2O), and contributing to a modest adsorption capacity for Ni2+ (15 mg/g) for the hydroxyapatite-containing waste putty.","PeriodicalId":51113,"journal":{"name":"Materiales de Construccion","volume":"70 1","pages":"220"},"PeriodicalIF":2.1,"publicationDate":"2020-04-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48549182","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}
Ercan Işık, A. Büyüksaraç, E. Avşar, M. F. Kuluöztürk, M. Günay
Bitlis rock is used as a construction material and comes from the lava emitted by volcanoes and their subsequent transformation into ignimbrites. This type of rocks has been characterized physically, chemically, toxicologically and radioactively using different procedures including determination of the coefficient of thermal conductivity, gamma spectrometry, ultrasonic speed test, ICP masses and metal extraction. The results indicate that Bitlis rocks have an ACI greater than 1, although their content of radon is lower than other rocks of volcanic origin. Leaching of metals from these rocks indicates that Pb and Cd can provide an infiltration level in the field higher than the level permitted by TCLP and they have undesired toxicological risks. The percentages of extraction of other metals also point to this infiltration problem. Despite this, the material offers good qualities for usage as a building material such as its thermal coefficients.
{"title":"Characteristics and properties of Bitlis ignimbrites and their environmental implications","authors":"Ercan Işık, A. Büyüksaraç, E. Avşar, M. F. Kuluöztürk, M. Günay","doi":"10.3989/mc.2020.06519","DOIUrl":"https://doi.org/10.3989/mc.2020.06519","url":null,"abstract":"Bitlis rock is used as a construction material and comes from the lava emitted by volcanoes and their subsequent transformation into ignimbrites. This type of rocks has been characterized physically, chemically, toxicologically and radioactively using different procedures including determination of the coefficient of thermal conductivity, gamma spectrometry, ultrasonic speed test, ICP masses and metal extraction. The results indicate that Bitlis rocks have an ACI greater than 1, although their content of radon is lower than other rocks of volcanic origin. Leaching of metals from these rocks indicates that Pb and Cd can provide an infiltration level in the field higher than the level permitted by TCLP and they have undesired toxicological risks. The percentages of extraction of other metals also point to this infiltration problem. Despite this, the material offers good qualities for usage as a building material such as its thermal coefficients.","PeriodicalId":51113,"journal":{"name":"Materiales de Construccion","volume":"70 1","pages":"214"},"PeriodicalIF":2.1,"publicationDate":"2020-04-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43002179","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}
R. Bustamante, P. Vázquez, P. Rodríguez-Monteverde, J. Monjo
The advanced condition of deterioration of the column’s bases of the courtyard of the Bishop’s Palace of Tarazona (Spain) built in the middle of 16th century required its restoration with Aragonese alabaster. Thus, adapted ageing tests were developed to simulate the environmental conditions in which the stones were and will be exposed. These tests were thermal fatigue by temperature variations, acid rain and water stagnation by immersion tests and a combination of both agents of decay. The results indicated that alabaster did not experimented deformation after thermal fatigue but a progressive dehydration to bassanite. This process entailed an increase of porosity and consequently a loss of structural properties. The dissolution was measured as a lineal weight and volume loss while porosity and capillary uptake remained stable. The conclusions of this study establish the importance of restoration protocols to maintain the alabaster integrity when used and exposed to rainwater and insolation.
{"title":"Adapted ageing tests for the evaluation of alabaster used in the restoration of Bishop’s Palace of Tarazona","authors":"R. Bustamante, P. Vázquez, P. Rodríguez-Monteverde, J. Monjo","doi":"10.3989/mc.2020.08619","DOIUrl":"https://doi.org/10.3989/mc.2020.08619","url":null,"abstract":"The advanced condition of deterioration of the column’s bases of the courtyard of the Bishop’s Palace of Tarazona (Spain) built in the middle of 16th century required its restoration with Aragonese alabaster. Thus, adapted ageing tests were developed to simulate the environmental conditions in which the stones were and will be exposed. These tests were thermal fatigue by temperature variations, acid rain and water stagnation by immersion tests and a combination of both agents of decay. The results indicated that alabaster did not experimented deformation after thermal fatigue but a progressive dehydration to bassanite. This process entailed an increase of porosity and consequently a loss of structural properties. The dissolution was measured as a lineal weight and volume loss while porosity and capillary uptake remained stable. The conclusions of this study establish the importance of restoration protocols to maintain the alabaster integrity when used and exposed to rainwater and insolation.","PeriodicalId":51113,"journal":{"name":"Materiales de Construccion","volume":"70 1","pages":"219"},"PeriodicalIF":2.1,"publicationDate":"2020-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46628631","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}
G. Thalmaier, N. Cobîrzan, A. Balog, H. Constantinescu, M. Streza, M. Nasui, B. Neamțu
This study investigates the effect of adding different size fractions of the same pore forming agent (sawdust) on the material’s compressive strength and heat transfer. The samples were dry pressed and fired at high temperature inside an oven. Phase transformations were evidenced by a combination of differential thermal analysis, thermogravimetry and mass spectrometry (DTA-TGA-MS) and X-ray diffraction (XRD) techniques, in the temperature range of 24-900 oC. Image analysis (IA) and compression tests were performed to explain the mechanical behaviour of the samples. The thermal conductivity was obtained by using combined photopyroelectric calorimetry (PPE) and lock-in thermography (LIT) techniques. The pressing direction has an impact on the distribution of pores and the heat transfer by conduction.
{"title":"Influence of sawdust particle size on fired clay brick properties","authors":"G. Thalmaier, N. Cobîrzan, A. Balog, H. Constantinescu, M. Streza, M. Nasui, B. Neamțu","doi":"10.3989/mc.2020.04219","DOIUrl":"https://doi.org/10.3989/mc.2020.04219","url":null,"abstract":"This study investigates the effect of adding different size fractions of the same pore forming agent (sawdust) on the material’s compressive strength and heat transfer. The samples were dry pressed and fired at high temperature inside an oven. Phase transformations were evidenced by a combination of differential thermal analysis, thermogravimetry and mass spectrometry (DTA-TGA-MS) and X-ray diffraction (XRD) techniques, in the temperature range of 24-900 oC. Image analysis (IA) and compression tests were performed to explain the mechanical behaviour of the samples. The thermal conductivity was obtained by using combined photopyroelectric calorimetry (PPE) and lock-in thermography (LIT) techniques. The pressing direction has an impact on the distribution of pores and the heat transfer by conduction.","PeriodicalId":51113,"journal":{"name":"Materiales de Construccion","volume":"70 1","pages":"215"},"PeriodicalIF":2.1,"publicationDate":"2020-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43746479","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}
Polymers are known to improve the fatigue resistance of sphalt mastics. However, undesirable results can be obtained if the polymer is not successfully integrated into the bitumen binder. The goal of this work is to evaluate the effect of the addition of three selected polyolefins on their mastic’s fatigue performance. Low and high density polyethylenes (LDPE and HDPE) and polypropylene (PP) were chosen and used at the concentration of 4 wt.%. A dissipated energy approach was used in order to analyze the fatigue resistance, at 25 oC, of the three composites studied. Dynamic time sweeps at and above the linear viscoelastic threshold were carried out. Based on that, the results demonstrated a better improvement when the LDPE was considered. For that binder, fluorescence optical microscopy observations at 25 oC provided morphological evidence of a more homogeneous bitumen-polymer distribution which could be behind the improved fatigue behavior.
{"title":"Fatigue performance evaluation of bitumen mastics reinforced with polyolefins through a dissipated energy approach","authors":"C. Roman, M. Delgado, M. García-Morales","doi":"10.3989/mc.2020.09319","DOIUrl":"https://doi.org/10.3989/mc.2020.09319","url":null,"abstract":"Polymers are known to improve the fatigue resistance of sphalt mastics. However, undesirable results can be obtained if the polymer is not successfully integrated into the bitumen binder. The goal of this work is to evaluate the effect of the addition of three selected polyolefins on their mastic’s fatigue performance. Low and high density polyethylenes (LDPE and HDPE) and polypropylene (PP) were chosen and used at the concentration of 4 wt.%. A dissipated energy approach was used in order to analyze the fatigue resistance, at 25 oC, of the three composites studied. Dynamic time sweeps at and above the linear viscoelastic threshold were carried out. Based on that, the results demonstrated a better improvement when the LDPE was considered. For that binder, fluorescence optical microscopy observations at 25 oC provided morphological evidence of a more homogeneous bitumen-polymer distribution which could be behind the improved fatigue behavior.","PeriodicalId":51113,"journal":{"name":"Materiales de Construccion","volume":"70 1","pages":"217"},"PeriodicalIF":2.1,"publicationDate":"2020-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43821071","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}
L. Santillán, F. Locati, Y. Villagrán-Zaccardi, C. Zega
The effect of recycled concrete aggregate (RCA) on concrete performance against external sulfate attack (ESA) is not yet fully known. In this paper, recycled aggregate concretes (RAC) with 0, 50, 75 and 100% of RCA contents were evaluated after 10 years of exposure immersed in 50g/l sodium sulfate solution. Sulfate ingress profiles were obtained by wet chemical analyses and FRX. Also, the mineralogy of the ingress profile was evaluated by thermogravimetric analyses. Finally, microcracking development in samples was evaluated by optical fluorescent microscopy image analysis. Although RAC showed a slight increase in sulfate ingress, due to its higher porosity (about 30% higher SO3 content near the surface for 50% or higher replacement ratio than control concrete), a dense new matrix still allows a good performance of RAC to external sulfate attack with even 100% RCA content.
{"title":"Long-term sulfate attack on recycled aggregate concrete immersed in sodium sulfate solution for 10 years","authors":"L. Santillán, F. Locati, Y. Villagrán-Zaccardi, C. Zega","doi":"10.3989/mc.2020.06319","DOIUrl":"https://doi.org/10.3989/mc.2020.06319","url":null,"abstract":"The effect of recycled concrete aggregate (RCA) on concrete performance against external sulfate attack (ESA) is not yet fully known. In this paper, recycled aggregate concretes (RAC) with 0, 50, 75 and 100% of RCA contents were evaluated after 10 years of exposure immersed in 50g/l sodium sulfate solution. Sulfate ingress profiles were obtained by wet chemical analyses and FRX. Also, the mineralogy of the ingress profile was evaluated by thermogravimetric analyses. Finally, microcracking development in samples was evaluated by optical fluorescent microscopy image analysis. Although RAC showed a slight increase in sulfate ingress, due to its higher porosity (about 30% higher SO3 content near the surface for 50% or higher replacement ratio than control concrete), a dense new matrix still allows a good performance of RAC to external sulfate attack with even 100% RCA content.","PeriodicalId":51113,"journal":{"name":"Materiales de Construccion","volume":"70 1","pages":"212"},"PeriodicalIF":2.1,"publicationDate":"2020-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46648299","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}
Fibre-reinforced concrete (FRC) allows reduction in, or substitution of, steel-bars to reinforce concrete and led to the commonly named structural FRC, with steel fibres being the most widespread. Macro-polymer fibres are an alternative to steel fibres, being the main benefits: chemical stability and lower weight for analogous residual strengths of polyolefin-fibre-reinforced concrete (PFRC). Furthermore, polyolefin fibres offer additional advantages such as safe-handling, low pump-wear, light weight in transport and storage, and an absence of corrosion. Other studies have also revealed environmental benefits. After 30 years of research and practice, there remains a need to review the opportunities that such a type of fibre may provide for structural FRC. This study seeks to show the advances and future challenges of use of these polyolefin fibres and summarise the main properties obtained in both fresh and hardened states of PFRC, focussing on the residual strengths obtained from flexural tensile tests.
{"title":"Recent advances in structural fibre-reinforced concrete focused on polyolefin-based macro-synthetic fibres","authors":"M. G. Alberti, A. Enfedaque, J. Gálvez, Á. Picazo","doi":"10.3989/mc.2020.12418","DOIUrl":"https://doi.org/10.3989/mc.2020.12418","url":null,"abstract":"Fibre-reinforced concrete (FRC) allows reduction in, or substitution of, steel-bars to reinforce concrete and led to the commonly named structural FRC, with steel fibres being the most widespread. Macro-polymer fibres are an alternative to steel fibres, being the main benefits: chemical stability and lower weight for analogous residual strengths of polyolefin-fibre-reinforced concrete (PFRC). Furthermore, polyolefin fibres offer additional advantages such as safe-handling, low pump-wear, light weight in transport and storage, and an absence of corrosion. Other studies have also revealed environmental benefits. After 30 years of research and practice, there remains a need to review the opportunities that such a type of fibre may provide for structural FRC. This study seeks to show the advances and future challenges of use of these polyolefin fibres and summarise the main properties obtained in both fresh and hardened states of PFRC, focussing on the residual strengths obtained from flexural tensile tests.","PeriodicalId":51113,"journal":{"name":"Materiales de Construccion","volume":"70 1","pages":"206"},"PeriodicalIF":2.1,"publicationDate":"2020-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43158660","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}
B. Qu, A. Fernández Jiménez, A. Palomo, A. Martin, J. Pastor
The high-temperature mechanical behaviour of a pre-industrial hybrid alkaline cement (HYC) was studied. The HYC in question contained 30 % Portland clinker and 70 % of a blend of slag, fly ash and a solid activator (mix of alkaline salts with a predominance of Na 2 SO 4 ). The material was tested during exposure to high temperatures to establish its compressive and bending strength and elastic modulus, as well as fracture toughness, analysed using an innovative methodology to notch the hydrated cement paste specimens. Post-thermal treatment tests were also run to assess residual mechanical strength after 2 h of exposure to temperatures ranging from 400 °C to 1000 °C. TG/DTA, MIP and SEM were deployed to ascertain heat-induced physical-chemical changes in the structure. The higher mechanical strength during and after treatment exhibited by the hardened hybrid alkaline cement than the CEM I 42.5R ordinary portland cement (OPC) paste used as a reference was associated with the lower water and portlandite content found in HYC. Pseudo-plastic behaviour was observed at high temperatures in the loaded HYC in the tests conducted during exposure.
研究了工业化前混合碱性水泥（HYC）的高温力学行为。所讨论的HYC含有30%的波特兰熟料和70%的矿渣、粉煤灰和固体活化剂的混合物（碱性盐的混合物，主要是Na2SO4）。在暴露于高温的过程中对该材料进行了测试，以确定其压缩和弯曲强度、弹性模量以及断裂韧性，并使用创新的方法对水合水泥浆试样进行了分析。还进行了热处理后试验，以评估暴露在400°C至1000°C温度下2小时后的残余机械强度。采用TG/DTA、MIP和SEM来确定热引起的结构的物理化学变化。硬化混合碱性水泥在处理期间和处理后表现出比用作参考的CEM I 42.5R普通硅酸盐水泥（OPC）浆体更高的机械强度，这与HYC中发现的较低的水和硅酸盐含量有关。在暴露期间进行的测试中，在高温下在负载的HYC中观察到伪塑性行为。
{"title":"Effect of high temperatures on the mechanical behaviour of hybrid cement","authors":"B. Qu, A. Fernández Jiménez, A. Palomo, A. Martin, J. Pastor","doi":"10.3989/mc.2020.13318","DOIUrl":"https://doi.org/10.3989/mc.2020.13318","url":null,"abstract":"The high-temperature mechanical behaviour of a pre-industrial hybrid alkaline cement (HYC) was studied. The HYC in question contained 30 % Portland clinker and 70 % of a blend of slag, fly ash and a solid activator (mix of alkaline salts with a predominance of Na 2 SO 4 ). The material was tested during exposure to high temperatures to establish its compressive and bending strength and elastic modulus, as well as fracture toughness, analysed using an innovative methodology to notch the hydrated cement paste specimens. Post-thermal treatment tests were also run to assess residual mechanical strength after 2 h of exposure to temperatures ranging from 400 °C to 1000 °C. TG/DTA, MIP and SEM were deployed to ascertain heat-induced physical-chemical changes in the structure. The higher mechanical strength during and after treatment exhibited by the hardened hybrid alkaline cement than the CEM I 42.5R ordinary portland cement (OPC) paste used as a reference was associated with the lower water and portlandite content found in HYC. Pseudo-plastic behaviour was observed at high temperatures in the loaded HYC in the tests conducted during exposure.","PeriodicalId":51113,"journal":{"name":"Materiales de Construccion","volume":"70 1","pages":"213"},"PeriodicalIF":2.1,"publicationDate":"2020-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45861077","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}
V. Bonavetti, V. Rahhal, F. Locati, E. Irassar, S. Marfil, P. Maiza
A vitreous breccia with variable amount of mordenite was studied for its use as pozzolan. The raw material was characterized by optical and scanning electron microscopy (SEM), X-ray diffraction (XRD), and the zeolite content was estimated by the methylene blue staining technique. After being ground, physical characteristics, cation exchange capacity (CEC), pozzolanicity, and the compressive strength activity index (SAI) were determined. The staining technique and the CEC measurement were used to evaluate the average content of zeolite. The vitreous breccia has pozzolanic activity after 7 days, the water demand increases slightly, and its addition stimulates the early hydration of portland cement. At later ages, the pozzolanic reaction around the grains, as revealed by SEM studies, improves the compressive strength of blended cements having a SAI > 0.85 at 28 days.
{"title":"Pozzolanic activity of argentine vitreous breccia containing mordenite","authors":"V. Bonavetti, V. Rahhal, F. Locati, E. Irassar, S. Marfil, P. Maiza","doi":"10.3989/mc.2020.04019","DOIUrl":"https://doi.org/10.3989/mc.2020.04019","url":null,"abstract":"A vitreous breccia with variable amount of mordenite was studied for its use as pozzolan. The raw material was characterized by optical and scanning electron microscopy (SEM), X-ray diffraction (XRD), and the zeolite content was estimated by the methylene blue staining technique. After being ground, physical characteristics, cation exchange capacity (CEC), pozzolanicity, and the compressive strength activity index (SAI) were determined. The staining technique and the CEC measurement were used to evaluate the average content of zeolite. The vitreous breccia has pozzolanic activity after 7 days, the water demand increases slightly, and its addition stimulates the early hydration of portland cement. At later ages, the pozzolanic reaction around the grains, as revealed by SEM studies, improves the compressive strength of blended cements having a SAI > 0.85 at 28 days.","PeriodicalId":51113,"journal":{"name":"Materiales de Construccion","volume":"70 1","pages":"208"},"PeriodicalIF":2.1,"publicationDate":"2020-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43129920","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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