Pub Date : 2024-07-27DOI: 10.32047/cwb.2024.29.1.4
L. Húlek, M. Bačuvčík, Michal Cápay, I. Janotka
In 2021, cement plants in Slovakia started production of Portland composite cement of CEM II/C-M type according to STN EN 197-5. The main objective is to reduce the carbon footprint in the production of types of cement characterized by lower clinker content. The application of this cement is currently limited because the construction product standards only accept the use of types of cement according to STN EN 197-1. For types of cement meeting the STN EN 197-5 requirements, the general suitability of their use in concrete according to STN EN 206+A2 is not indicated. The applicability of individual types of cement only according to STN EN 197-1 for exposure classes XC, XF, XD, and XA is specified in the National Annex (STN EN 206+A2/NA). The suitability of the use of new cement concrete must therefore be demonstrated. The aim of the research carried out was to clarify the potential of using CEM II/C-M (S-LL) in practice. This article presents the results of a research project aimed at verifying the suitability of CEM II/CM (S-LL) for use in concrete following the requirements of STN EN 206+A2.
2021 年，斯洛伐克的水泥厂开始根据 STN EN 197-5 标准生产 CEM II/C-M 型波特兰复合水泥。其主要目的是在生产熟料含量较低的水泥类型时减少碳足迹。由于建筑产品标准只接受使用符合 STN EN 197-1 标准的水泥类型，因此这种水泥的应用目前受到限制。对于符合 STN EN 197-5 要求的水泥类型，STN EN 206+A2 并未指出其在混凝土中的一般适用性。国家附件（STN EN 206+A2/NA）中规定了 STN EN 197-1 仅适用于 XC、XF、XD 和 XA 暴露等级的个别水泥类型。因此，必须证明新水泥混凝土的适用性。研究的目的是明确在实践中使用 CEM II/C-M (S-LL) 的可能性。本文介绍了一项研究项目的成果，该项目旨在验证 CEM II/CM (S-LL) 是否适合用于符合 STN EN 206+A2 要求的混凝土中。
{"title":"Perspective of concrete with Portland composite cement CEM II/C-M (S-LL)","authors":"L. Húlek, M. Bačuvčík, Michal Cápay, I. Janotka","doi":"10.32047/cwb.2024.29.1.4","DOIUrl":"https://doi.org/10.32047/cwb.2024.29.1.4","url":null,"abstract":"In 2021, cement plants in Slovakia started production of Portland composite cement of CEM II/C-M type according to STN EN 197-5. The main objective is to reduce the carbon footprint in the production of types of cement characterized by lower clinker content. The application of this cement is currently limited because the construction product standards only accept the use of types of cement according to STN EN 197-1. For types of cement meeting the STN EN 197-5 requirements, the general suitability of their use in concrete according to STN EN 206+A2 is not indicated. The applicability of individual types of cement only according to STN EN 197-1 for exposure classes XC, XF, XD, and XA is specified in the National Annex (STN EN 206+A2/NA). The suitability of the use of new cement concrete must therefore be demonstrated. The aim of the research carried out was to clarify the potential of using CEM II/C-M (S-LL) in practice. This article presents the results of a research project aimed at verifying the suitability of CEM II/CM (S-LL) for use in concrete following the requirements of STN EN 206+A2.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141797908","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}
Pub Date : 2024-07-27DOI: 10.32047/cwb.2024.29.1.3
G. Atay, V. Loboichenko, J. Wilk-Jakubowski
This work examines the characteristics of mineral additives in wood composites that affect the fire retardant properties of the material, and at the same time are environmentally friendly. The paper analyzes the results of measurements for wood composites, which is the natural building material of many houses, as well as elements of their furnishings. Sawdust waste was applied as a matrix. In the paper, a co-presence effect of calcite and huntite/hydromagnesite mineral was investigated. The calcite mineral was used as auxiliary minerals in addition to the huntite/hydromagnesite mineral to obtain a better flame retardant according to the UL94 standard and mechanical properties in the wood composite, such as flexural strength and flexural modulus. The results obtained were measured and evaluated depending on the mineral content of the composites. The results indicated that sample 40S/ 50H/ 10C is the most optimal in terms of the ratio of the modulus of flexibility and fire retardant characteristics. Fire retardant materials can be used in the construction industry, as well as in the electrical engineering applications, such as for acoustic fire extinguishers [e.g. for waveguide construction].
{"title":"Investigation of calcite and huntite/hydromagnesite mineral in co-presence regarding flame retardant and mechanical properties of wood composites","authors":"G. Atay, V. Loboichenko, J. Wilk-Jakubowski","doi":"10.32047/cwb.2024.29.1.3","DOIUrl":"https://doi.org/10.32047/cwb.2024.29.1.3","url":null,"abstract":"This work examines the characteristics of mineral additives in wood composites that affect the fire retardant properties of the material, and at the same time are environmentally friendly. The paper analyzes the results of measurements for wood composites, which is the natural building material of many houses, as well as elements of their furnishings. Sawdust waste was applied as a matrix. In the paper, a co-presence effect of calcite and huntite/hydromagnesite mineral was investigated. The calcite mineral was used as auxiliary minerals in addition to the huntite/hydromagnesite mineral to obtain a better flame retardant according to the UL94 standard and mechanical properties in the wood composite, such as flexural strength and flexural modulus. The results obtained were measured and evaluated depending on the mineral content of the composites. The results indicated that sample 40S/ 50H/ 10C is the most optimal in terms of the ratio of the modulus of flexibility and fire retardant characteristics. Fire retardant materials can be used in the construction industry, as well as in the electrical engineering applications, such as for acoustic fire extinguishers [e.g. for waveguide construction].","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141797469","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}
The performance of concrete / mortar is specially related to their composition and water to cement ratio. The use of Ordinary Portland cement [OPC] as binder increases the hydration heat and cost of cement and CO2 emissions. So the use of composite binder by reducing the amount of OPC and introducing mineral additions can be a useful solution. In this study, OPC was partially substituted with marble powder [MP] at various percentages (5, 10, 15 and 20%) and the effect of MP on the durability of self compacting mortars [SCM] exposed to chemical aggressions was investigated. Two aggressive solutions were used sodium sulfate [Na2SO4] and hydrochloric acid [HCl]. The dosages of the solutions were 5 and 1%, respectively. The results revealed that the use of marble powder is beneficial for improving the resistance of SCM to aggressive solutions. Adding 20% MP increased the resistance against sodium sulfate attack by 46% at 180 days. Using MP with content ranged between 10 to 20% was found to reduce mass loss by 1 to 0.47%.
{"title":"Durability self-compacting mortar under external chemical attacks based on composite binder","authors":"Benguit Amar, Aboubakeur Boukhelkhal, Azzouz Lakhdar","doi":"10.32047/cwb.2024.29.1.5","DOIUrl":"https://doi.org/10.32047/cwb.2024.29.1.5","url":null,"abstract":"The performance of concrete / mortar is specially related to their composition and water to cement ratio. The use of Ordinary Portland cement [OPC] as binder increases the hydration heat and cost of cement and CO2 emissions. So the use of composite binder by reducing the amount of OPC and introducing mineral additions can be a useful solution. In this study, OPC was partially substituted with marble powder [MP] at various percentages (5, 10, 15 and 20%) and the effect of MP on the durability of self compacting mortars [SCM] exposed to chemical aggressions was investigated. Two aggressive solutions were used sodium sulfate [Na2SO4] and hydrochloric acid [HCl]. The dosages of the solutions were 5 and 1%, respectively. The results revealed that the use of marble powder is beneficial for improving the resistance of SCM to aggressive solutions. Adding 20% MP increased the resistance against sodium sulfate attack by 46% at 180 days. Using MP with content ranged between 10 to 20% was found to reduce mass loss by 1 to 0.47%.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-07-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141797679","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}
Pub Date : 2024-07-24DOI: 10.32047/cwb.2024.29.1.1
J. Shanmugapriya, K. Chinnaraju
Proper curing of concrete has a major beneficial effect on the transport properties of concrete which in turn influences its durability. This paper attempts to study the effect of fly ash on the transport properties of internally cured Self-Compacting Concrete specimens under ambient conditions. Two internal curing materials, Lightweight Expanded Clay Aggregates [LECA] and Superabsorbent Polymer [SAP] were chosen for the study. Properties such as sorptivity, resistance to chloride ion penetration and chloride ion migration specimens with varying percentages of fly ash replacement from 30% to 50% are presented under different curing conditions namely conventional curing, sealed curing with internal curing materials and ambient curing with internal curing materials. The results showed that the impermeability of concrete improved with an increasing percentage of fly ash replacements owing to the presence of internal curing water to improve hydration along with fly ash that moderates the heat of hydration and drying. The internal curing efficiency also improved with the increase in the percentage of fly ash replacement. Under ambient conditions, the mixes with fly ash above 45% replacement have shown very good mechanical and durability properties indicating a refined pore structure leading to enhanced transport properties.
{"title":"Transport Properties of Internally Cured Self Compacting Concrete with Fly Ash","authors":"J. Shanmugapriya, K. Chinnaraju","doi":"10.32047/cwb.2024.29.1.1","DOIUrl":"https://doi.org/10.32047/cwb.2024.29.1.1","url":null,"abstract":"Proper curing of concrete has a major beneficial effect on the transport properties of concrete which in turn influences its durability. This paper attempts to study the effect of fly ash on the transport properties of internally cured Self-Compacting Concrete specimens under ambient conditions. Two internal curing materials, Lightweight Expanded Clay Aggregates [LECA] and Superabsorbent Polymer [SAP] were chosen for the study. Properties such as sorptivity, resistance to chloride ion penetration and chloride ion migration specimens with varying percentages of fly ash replacement from 30% to 50% are presented under different curing conditions namely conventional curing, sealed curing with internal curing materials and ambient curing with internal curing materials. The results showed that the impermeability of concrete improved with an increasing percentage of fly ash replacements owing to the presence of internal curing water to improve hydration along with fly ash that moderates the heat of hydration and drying. The internal curing efficiency also improved with the increase in the percentage of fly ash replacement. Under ambient conditions, the mixes with fly ash above 45% replacement have shown very good mechanical and durability properties indicating a refined pore structure leading to enhanced transport properties.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141807875","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}
Pub Date : 2024-07-24DOI: 10.32047/cwb.2024.29.1.2
Jacek Michalak
The article presents the current state of knowledge in assessing the environmental impact of construction products. The analysis was carried out to examine the possibility of reliable assessment and verification of the environmental impact of construction products by the manufacturer in connection with the planned introduction of mandatory environmental assessment in the EU. The results of a systematic literature review for the keywords of this article indicated many different problems and imperfections in the existing assessment model using product life cycle analysis, among which the most important is the incomparability of the results obtained, which is a crucial issue related to the manufacturer’s credibility. The literature review indicated that implementing a new, mandatory model for assessing the environmental impact of construction products in EU countries will be a challenge for all market participants. The rational implementation of the environmental assessment of construction products will be complex and require much more work and time than was planned by the European Commission. A comparison of the results of this literature review with the assumptions of the new EU model of environmental assessment of construction products also indicates the lack of knowledge transfer from science to public administration, negatively affecting the rationality of the decision-making process. In light of the literature review results, the only reasonable solution is to create sectoral environmental declarations. Adopting such a solution will allow manufacturers of construction products to rationalize the expenses related to their development and avoid the chaos that may arise when environmental impact data are incomparable.
{"title":"Environmental Assessment of Construction Products – Challenges, Priorities, and Needs from Producers’ Perspective. A Review","authors":"Jacek Michalak","doi":"10.32047/cwb.2024.29.1.2","DOIUrl":"https://doi.org/10.32047/cwb.2024.29.1.2","url":null,"abstract":"The article presents the current state of knowledge in assessing the environmental impact of construction products. The analysis was carried out to examine the possibility of reliable assessment and verification of the environmental impact of construction products by the manufacturer in connection with the planned introduction of mandatory environmental assessment in the EU. The results of a systematic literature review for the keywords of this article indicated many different problems and imperfections in the existing assessment model using product life cycle analysis, among which the most important is the incomparability of the results obtained, which is a crucial issue related to the manufacturer’s credibility. The literature review indicated that implementing a new, mandatory model for assessing the environmental impact of construction products in EU countries will be a challenge for all market participants. The rational implementation of the environmental assessment of construction products will be complex and require much more work and time than was planned by the European Commission. A comparison of the results of this literature review with the assumptions of the new EU model of environmental assessment of construction products also indicates the lack of knowledge transfer from science to public administration, negatively affecting the rationality of the decision-making process. In light of the literature review results, the only reasonable solution is to create sectoral environmental declarations. Adopting such a solution will allow manufacturers of construction products to rationalize the expenses related to their development and avoid the chaos that may arise when environmental impact data are incomparable.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":null,"pages":null},"PeriodicalIF":0.5,"publicationDate":"2024-07-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141809456","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}
Pub Date : 2024-06-06DOI: 10.32047/cwb.2023.28.6.3
P. Wichowski, Marek Kalenik, G. Rutkowska, M. Malarski, Justyna Czajkowska, Wojciech Franus
The article presents an analysis of the results of research on the composition of fly ash from the thermal processing of sewage sludge [SSA] collected from three incineration plants located in Warsaw, Cracow and Łódź. It determines the leaching values of selected heavy metals from the tested fly ash and ordinary class concrete C20/25 with partial replacement - up to 20% of cement with fly ash. The laboratory tests performed showed that they have a comparable granulometric composition. In contrast, the physico-chemical properties of the tested fly ashes differ from ashes from coal combustion traditionally used in concrete technology. SSA is characterized by an average lower content of silicon, iron, and aluminium oxides with a much higher content of phosphorus oxides. Leaching tests indicate low mobility of heavy metals, meeting Polish regulations regarding the possibility of using SSA in construction for specific applications. At the same time, they do not pose a significant threat to human health or the environment. Construction waste containing SSA may be disposed of in inert waste landfills.
{"title":"Characteristics of products made in the process solidification and stabilization of fly ash from combustion of sewage sludge","authors":"P. Wichowski, Marek Kalenik, G. Rutkowska, M. Malarski, Justyna Czajkowska, Wojciech Franus","doi":"10.32047/cwb.2023.28.6.3","DOIUrl":"https://doi.org/10.32047/cwb.2023.28.6.3","url":null,"abstract":"The article presents an analysis of the results of research on the composition of fly ash from the thermal processing of sewage sludge [SSA] collected from three incineration plants located in Warsaw, Cracow and Łódź. It determines the leaching values of selected heavy metals from the tested fly ash and ordinary class concrete C20/25 with partial replacement - up to 20% of cement with fly ash. The laboratory tests performed showed that they have a comparable granulometric composition. In contrast, the physico-chemical properties of the tested fly ashes differ from ashes from coal combustion traditionally used in concrete technology. SSA is characterized by an average lower content of silicon, iron, and aluminium oxides with a much higher content of phosphorus oxides. Leaching tests indicate low mobility of heavy metals, meeting Polish regulations regarding the possibility of using SSA in construction for specific applications. At the same time, they do not pose a significant threat to human health or the environment. Construction waste containing SSA may be disposed of in inert waste landfills.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141379262","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}
Pub Date : 2024-06-06DOI: 10.32047/cwb.2023.28.6.5
Hanaa Ghorab, Mostafa Abbas, Ahmed Arafa, Hassan Hassan
A reference belite is prepared from burning calcite and quartz (mole ratio= 2), 1.5 hours at 1200°C. The belite polymorphs formed in presence of Li2CO3 with 1% Li2O, as fluxing and doping agent, in addition to SrCO3 and BaCO3 with amounts equivalent to 8% SrO and 8% BaO, as mineralizers, are identified. The thermal behaviors of the belite mixes and of the pure carbonates are recorded for temperatures up to 1300°C. The polymorphs formed are defined by means of X-ray Rietveld analysis, and are examined under a scanning electron microscope. It is found that the beta and gama polymorphs are equally formed in the belite doped with strontium, and in presence of barium, the alpha’ appears as well. The decomposition of Li2CO3 to Li2O is depressed by strontium and barium carbonates due to the increase in the partial pressure of CO2 and consequently the melt is stabilized. .Further research is needed to explain the effect of CO2 partial pressure of the carbonates on the polymorphism of belite.
{"title":"Effect of lithium, strontium and barium carbonates on the belite phase formed at 1200°C","authors":"Hanaa Ghorab, Mostafa Abbas, Ahmed Arafa, Hassan Hassan","doi":"10.32047/cwb.2023.28.6.5","DOIUrl":"https://doi.org/10.32047/cwb.2023.28.6.5","url":null,"abstract":"A reference belite is prepared from burning calcite and quartz (mole ratio= 2), 1.5 hours at 1200°C. The belite polymorphs formed in presence of Li2CO3 with 1% Li2O, as fluxing and doping agent, in addition to SrCO3 and BaCO3 with amounts equivalent to 8% SrO and 8% BaO, as mineralizers, are identified. The thermal behaviors of the belite mixes and of the pure carbonates are recorded for temperatures up to 1300°C. The polymorphs formed are defined by means of X-ray Rietveld analysis, and are examined under a scanning electron microscope. It is found that the beta and gama polymorphs are equally formed in the belite doped with strontium, and in presence of barium, the alpha’ appears as well. The decomposition of Li2CO3 to Li2O is depressed by strontium and barium carbonates due to the increase in the partial pressure of CO2 and consequently the melt is stabilized. .Further research is needed to explain the effect of CO2 partial pressure of the carbonates on the polymorphism of belite.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141378450","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}
Pub Date : 2024-06-05DOI: 10.32047/cwb.2023.28.6.4
M. Glinicki, D. Jóźwiak-Niedźwiedzka, Andrzej M. Brandt
The article presents the diagnostic results on surface-hardened industrial concrete floors. Selected examples of floors showcased premature damage to surface layers, characterized by intense dusting, delamination, and local spalling, while the structural system remained unaffected. Quantitative petrographic analysis of concrete was applied to core specimens from the floors, involving the examination of digital images from a polarizing optical microscope and a scanning electron microscope. The hardening compound and powdered specimens of the cement matrix were characterized using differential thermal analysis and X-ray diffraction. A multiple microindentation method was employed to assess local variations in mechanical properties. Concrete cross-section analysis revealed areas with a non-uniform distribution of air voids, identified regions exhibiting increased porosity, highlighted areas of cracking in the concrete, indicated local variability in the phase composition of cement hydration products, and pointed out the presence of carbonated areas. The causes of the damage were discussed based on these findings,. The crucial role of quantitative petrographic analysis in diagnosing premature surface damage to industrial floors was demonstrated.
文章介绍了对表面硬化的工业混凝土地面的诊断结果。所选地板实例显示了表层的过早损坏，其特点是严重起灰、分层和局部剥落，而结构系统则未受影响。通过偏光光学显微镜和扫描电子显微镜的数字图像检查，对来自地面的核心试样进行了混凝土定量岩相分析。利用差热分析和 X 射线衍射对硬化化合物和水泥基质粉末试样进行了表征。采用多重微压痕法评估了机械性能的局部变化。混凝土横截面分析显示了气孔分布不均匀的区域，确定了孔隙率增加的区域，突出了混凝土开裂的区域，显示了水泥水化产物相组成的局部变化，并指出了碳化区域的存在。根据这些发现讨论了损坏的原因。定量岩相分析在诊断工业地面过早表面损坏方面的关键作用得到了证明。
{"title":"Diagnostics of premature damage to surface-hardened industrial concrete floors","authors":"M. Glinicki, D. Jóźwiak-Niedźwiedzka, Andrzej M. Brandt","doi":"10.32047/cwb.2023.28.6.4","DOIUrl":"https://doi.org/10.32047/cwb.2023.28.6.4","url":null,"abstract":"The article presents the diagnostic results on surface-hardened industrial concrete floors. Selected examples of floors showcased premature damage to surface layers, characterized by intense dusting, delamination, and local spalling, while the structural system remained unaffected. Quantitative petrographic analysis of concrete was applied to core specimens from the floors, involving the examination of digital images from a polarizing optical microscope and a scanning electron microscope. The hardening compound and powdered specimens of the cement matrix were characterized using differential thermal analysis and X-ray diffraction. A multiple microindentation method was employed to assess local variations in mechanical properties. Concrete cross-section analysis revealed areas with a non-uniform distribution of air voids, identified regions exhibiting increased porosity, highlighted areas of cracking in the concrete, indicated local variability in the phase composition of cement hydration products, and pointed out the presence of carbonated areas. The causes of the damage were discussed based on these findings,. The crucial role of quantitative petrographic analysis in diagnosing premature surface damage to industrial floors was demonstrated.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141265621","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}
Pub Date : 2024-04-13DOI: 10.32047/cwb.2023.28.5.5
Z. Owsiak, Katarzyna Szczykutowicz
Geopolymers are amorphous materials produced by the polymerisation reaction between an aluminosilicate precursor and an alkaline reagent or by activation with phosphoric acid. The aluminosilicate raw material used in the manufacture of geopolymers an be industrial waste, such as fly ash or volcanic ash, blastfurnace slag, or it can be obtained from natural raw materials, such as metakaolin and meta-halloysite. The work aimed to select the composition of an activator for the production of meta-halloysite geopolymers with optimum physico-mechanical properties such as specific and bulk density, porosity, weight, and bulk absorption, as well as flexural and compressive strength. A two-factor experimental design was employed to determine the composition of the alkaline activator for geopolymer mortars, with sodium hydroxide solution molar concentration and sodium silicate to NaOH ratio as variables. Research has shown that increasing the amount of sodium silicate relative to the mass of a 12M NaOH solution in the activator solution improves the compressive strength of geopolymers by 36.8%, while an increase in flexural strength of 14.2% was achieved. As the molar concentration of caustic soda in the activator solution increases from 19.0 to 24.5%, the porosity of geopolymer mortars decreases. The reduction in the ratio of water glass to sodium hydroxide and the reduction in the molar concentration of NaOH increases the mass and volume water absorption of the mortar. Further studies is necessary to determine the optimal mixture of metahalloysite geopolymer, taking into account its functional properties and durability.
{"title":"Physical and mechanical properties of meta-halloysite-based geopolymer mortars","authors":"Z. Owsiak, Katarzyna Szczykutowicz","doi":"10.32047/cwb.2023.28.5.5","DOIUrl":"https://doi.org/10.32047/cwb.2023.28.5.5","url":null,"abstract":"Geopolymers are amorphous materials produced by the polymerisation reaction between an aluminosilicate precursor and an alkaline reagent or by activation with phosphoric acid. The aluminosilicate raw material used in the manufacture of geopolymers an be industrial waste, such as fly ash or volcanic ash, blastfurnace slag, or it can be obtained from natural raw materials, such as metakaolin and meta-halloysite. The work aimed to select the composition of an activator for the production of meta-halloysite geopolymers with optimum physico-mechanical properties such as specific and bulk density, porosity, weight, and bulk absorption, as well as flexural and compressive strength. A two-factor experimental design was employed to determine the composition of the alkaline activator for geopolymer mortars, with sodium hydroxide solution molar concentration and sodium silicate to NaOH ratio as variables. Research has shown that increasing the amount of sodium silicate relative to the mass of a 12M NaOH solution in the activator solution improves the compressive strength of geopolymers by 36.8%, while an increase in flexural strength of 14.2% was achieved. As the molar concentration of caustic soda in the activator solution increases from 19.0 to 24.5%, the porosity of geopolymer mortars decreases. The reduction in the ratio of water glass to sodium hydroxide and the reduction in the molar concentration of NaOH increases the mass and volume water absorption of the mortar. Further studies is necessary to determine the optimal mixture of metahalloysite geopolymer, taking into account its functional properties and durability.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-04-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140708660","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}
Pub Date : 2024-04-09DOI: 10.32047/cwb.2023.28.5.3
D. Madej, Andrzej Kruk
Calcium aluminate cements [CACs] are typically used for cast-in-place structural work and high temperature applications due to their unique properties. The CaAl2O4 [CA] and Sm-doped CaAl2O4 [CA:Sm] cement clinkers obtained by the solid-state reaction were investigated using X-ray powder diffraction [XRD], scanning electron microscopy [SEM] and energy dispersive X-ray spectroscopy [EDS] and luminescence spectroscopy. The XRD result shows that the powders are pure CaAl2O4. As a next step, hydration behavior of as-synthesized cements was investigated by both classical methods including isothermal calorimetry and XRD, and the state-of-the-art techniques including time resolved electrochemical impedance spectroscopy [TR-EIS] and luminescence spectroscopy. The TR-EIS investigations were obtained by the Impedance Camera over the range of 100 Hz to 1 MHz frequencies. The evolution of obtained EIS and luminescence spectra easily manifested the beginning of the new solid formation and the hydration kinetics. The dynamics of hydration processes were also successfully traced by the changes of the luminescence intensity from the Sm3+ ions. This technique seems to be complementary, and consistent with other methods implemented in the cement chemistry, especially to investigate e.g. hydration of ordinary Portland cements [OPCs] and other binders.
铝酸钙水泥因其独特的性能通常用于现浇结构工程和高温应用。本研究利用 X 射线粉末衍射 (XRD)、扫描电子显微镜 (SEM)、能量色散 X 射线光谱 (EDS) 和发光光谱对固态反应得到的 CaAl2O4 [CA] 和 Sm 掺杂 CaAl2O4 [CA:Sm] 水泥熟料进行了研究。XRD 结果表明，这些粉末是纯 CaAl2O4。下一步，通过等温量热法和 XRD 等经典方法，以及时间分辨电化学阻抗光谱法 [TR-EIS] 和发光光谱法等先进技术，对合成水泥的水化行为进行了研究。TR-EIS 研究是通过阻抗照相机在 100 Hz 至 1 MHz 频率范围内获得的。所获得的 EIS 和发光光谱的演变很容易显示出新固体形成的开始和水合动力学。通过 Sm3+ 离子发光强度的变化也成功地追踪了水合过程的动态。这种技术似乎是一种补充，并且与水泥化学中使用的其他方法一致，特别是在研究普通波特兰水泥 [OPCs] 和其他粘结剂的水化等方面。
{"title":"Classical and new insights into the methodology for characterizing the hydration of calcium aluminate cements","authors":"D. Madej, Andrzej Kruk","doi":"10.32047/cwb.2023.28.5.3","DOIUrl":"https://doi.org/10.32047/cwb.2023.28.5.3","url":null,"abstract":"Calcium aluminate cements [CACs] are typically used for cast-in-place structural work and high temperature applications due to their unique properties. The CaAl2O4 [CA] and Sm-doped CaAl2O4 [CA:Sm] cement clinkers obtained by the solid-state reaction were investigated using X-ray powder diffraction [XRD], scanning electron microscopy [SEM] and energy dispersive X-ray spectroscopy [EDS] and luminescence spectroscopy. The XRD result shows that the powders are pure CaAl2O4. As a next step, hydration behavior of as-synthesized cements was investigated by both classical methods including isothermal calorimetry and XRD, and the state-of-the-art techniques including time resolved electrochemical impedance spectroscopy [TR-EIS] and luminescence spectroscopy. The TR-EIS investigations were obtained by the Impedance Camera over the range of 100 Hz to 1 MHz frequencies. The evolution of obtained EIS and luminescence spectra easily manifested the beginning of the new solid formation and the hydration kinetics. The dynamics of hydration processes were also successfully traced by the changes of the luminescence intensity from the Sm3+ ions. This technique seems to be complementary, and consistent with other methods implemented in the cement chemistry, especially to investigate e.g. hydration of ordinary Portland cements [OPCs] and other binders.","PeriodicalId":55632,"journal":{"name":"Cement Wapno Beton","volume":null,"pages":null},"PeriodicalIF":0.7,"publicationDate":"2024-04-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140727163","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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