Effect of Supplementary Cementitious Materials on Reduction of CO2 Emissions From Concrete

The article presents studies of plain concretes prepared based on a quaternary binder containing various percentages of selected supplementary cementitious materials (SCMs). The possibilities of nanotechnology in concrete technology were also used. An additional important environmental goal of the proposed solution was to create the possibility of reducing CO2 emissions and the carbon footprint generated during the production of ordinary Portland cement (OPC). As the main substitute for the OPC, siliceous fly ash (FA) was used. Moreover, silica fume (SF) and nanosilica (nS) were also used. During examinations, the main mechanical properties of composites, i.e., compressive strength (fcm) and splitting tensile strength (fctm), were assessed. The microstructure of these materials was also analyzed using a scanning electron microscope (SEM). In addition to the experimental research, simulations of the possible reduction of CO2 emissions to the atmosphere, as a result of the proposed solutions, were also carried out. It was found that the quaternary concrete is characterized by a well-developed structure and has high values of mechanical parameters. Furthermore, the use of green concrete based on quaternary binders enables a significant reduction in CO2 emissions. Therefore quaternary green concrete containing SCMs could be a useful alternative to plain concretes covering both the technical and environmental aspects. The present study indicates that quaternary binders can perform better than OPC as far as mechanical properties and microstructures are concerned. Therefore they can be used during the production of durable concretes used to perform structures in traditional and industrial construction.

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The Influence of Chemical Activators on the Hydration Behavior and Technical Properties of Calcium Sulfoaluminate Cements Blended with Ground Granulated Blast Furnace Slags

Buildings ◽

10.3390/buildings11070268 ◽

2021 ◽

Vol 11 (7) ◽

pp. 268

Author(s):

Milena Marroccoli ◽

Antonio Telesca

Keyword(s):

Blast Furnace ◽

Co2 Emissions ◽

Cementitious Materials ◽

Supplementary Cementitious Materials ◽

X Ray Diffraction ◽

Cement Production ◽

Blended Cements ◽

Calcium Sulfoaluminate ◽

Technical Performance ◽

Technical Properties

The manufacture of Ordinary Portland cement (OPC) generates around 8% of the global CO2 emissions related to human activities. The last 20 years have seen considerable efforts in the research and development of methods to lower the carbon footprint associated with cement production. Specific focus has been on limiting the use of OPC and employing alternative binders, such as calcium sulfoaluminate (CSA) cements, namely special hydraulic binders obtained from non-Portland clinkers. CSA cements could be considered a valuable OPC alternative thanks to their distinctive composition and technical performance and the reduced environmental impact of their manufacturing process. To additionally reduce CO2 emissions, CSA cements can also be blended with supplementary cementitious materials. This paper investigates the influence of two separately added chemical activators (NaOH or Na2CO3) on the technical properties and hydration behavior of four CSA blended cements obtained by adding to a plain CSA cement two different ground granulated blast furnace slags. Differential thermal-thermogravimetric, X-ray diffraction and mercury intrusion porosimetry analyses were done, along with shrinkage/expansion and compressive strength measurements.

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Reactivity and Pozzolanic Properties of Biomass Ashes Generated by Wheat and Soybean Straw Combustion

Materials ◽

10.3390/ma14041004 ◽

2021 ◽

Vol 14 (4) ◽

pp. 1004

Author(s):

Slobodan Šupić ◽

Mirjana Malešev ◽

Vlastimir Radonjanin ◽

Vesna Bulatović ◽

Tiana Milović

Keyword(s):

Chemical Activation ◽

Cementitious Materials ◽

Silica Content ◽

Raw Material ◽

Supplementary Cementitious Materials ◽

Concrete Production ◽

Soybean Straw ◽

Reduction Of Co2 ◽

Straw Ash ◽

Biomass Ashes

A sustainable use of locally available wastes from agriculture as supplementary cementitious materials (SCMs) is an alternative solution for the prevention of excessive raw material usage, reduction of CO2 emission and cost-effective concrete production. This paper studies the reactivity of non-traditional waste SCMs: Wheat straw ash (WSA), mixture of wheat and soybean straw ash (WSSA) and soybean straw ash (SSA), which are abundant as agricultural by-products in Serbia. The chemical evaluation using XRF technique, thermal analysis (TGA/DSC), XRD and FTIR methods were performed along with physical properties tests to investigate the feasibility of utilizing biomass ashes as cement substitutes. The obtained results demonstrate a high pozzolanic activity of WSA, which is attributed to a high reactive silica content of the ash and its satisfactory level of fineness. A wider hump in XRD pattern of WSA compared to WSSA and SSA confirmed that it abounds in amorphous (reactive) phase. The insufficient activity index of soybean-based biomass ashes, characterized with a low silica content, was improved by additional grinding and/or blending with amorphous silica-rich material. This points out the mechanical activation, i.e., grinding procedure, and chemical activation, i.e., modification of the chemical composition, as techniques efficient at producing pozzolanic materials from biomass wastes. Tested biomass ashes are characterized with negligible leaching values of heavy metals, thereby satisfying eco-friendly principles of SCM utilization. The application of biomass ashes as SCMs leads to substantial cost savings, as well as benefits to the environment, such as lower consumption of cement, reduction of CO2 emissions during the production of cement and sustainable waste management.

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Diseño de mezclas de hormigones autocompactantes con alto contenido de adiciones minerales y áridos de diferentes naturaleza para desempeño en ambientes altamente agresivos

Libro de Comunicaciones / Livro das Comunicações ◽

10.4995/hac2018.2018.6324 ◽

2018 ◽

Author(s):

Javier Puentes Mojica ◽

Jose Luis Calvo ◽

M. Cruz Alonso Alonso

Keyword(s):

Power Plants ◽

Energy Transport ◽

Construction Materials ◽

Cementitious Materials ◽

Operating Conditions ◽

Supplementary Cementitious Materials ◽

Chemical Additives ◽

Concrete Type ◽

Mineral Additions ◽

Reduction Of Co2

The advances in the use of self-compacting concrete (SCC) increases its consumption in construction materials. The SCC has ease of placement and refinement of the microstructure due to the increase of the volume of paste and fines thus improving the resistance to the penetration of aggressive agents. Therefore, its use is not limited to usual scenarios but focusing also to environments with severe operating conditions as is the case of energy transport infrastructures, often located in remote and extreme places. These conditions of application and location restrict the type of materials to be used in the design of concrete: type of aggregates, type of cement, use of supplementary cementitious materials (SCM), etc. The development of SCC also must imply an increase in the sustainability of the construction process by promoting the use of binders with mineral additions and limestone filler , in order to reduce the total cement content (due to the reduction of CO2 emissions associated to cement production) thus decreasing their environmental footprint. However, the incorporation of SCM implies the need to ensure compatibility with the chemical additives, superplasticizers, while maintaining the fresh state properties. Another relevant factor is the type and characteristics of aggregates that significantly affect the workability of concrete. The aggregates provide an improvement in performance in a hardened state, but in some cases they modify the consistency losing the self-compactibility of the concrete.The aim of this study is to evaluate the influence of the composition of the mixture components on the fresh and hardened properties of the SCC: 1) Interaction of the additives with cements with high mineral addition content (50%) of slag and fly ash; 2) the effect of the use of mixtures of aggregates with different origin, shape and composition that provide the special properties required concentrated solar power plants. Mixtures of aggregates, limestone, basalt and crushed Clinker have been considered along with additives that promote flowability, water reducers and density enhancement. Robust SCCs can be developed with high stability suitable for CSP application.DOI: http://dx.doi.org/10.4995/HAC2018.2018.6324

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Assessing, Understanding and Unlocking Supplementary Cementitious Materials

RILEM Technical Letters ◽

10.21809/rilemtechlett.2016.12 ◽

2016 ◽

Vol 1 ◽

pp. 50 ◽

Cited By ~ 57

Author(s):

Ruben Snellings

Keyword(s):

Co2 Emissions ◽

Cementitious Materials ◽

Cement Industry ◽

Supplementary Cementitious Materials ◽

Partial Replacement ◽

New Materials ◽

Cement Production ◽

Blended Cements ◽

International Commitments ◽

Roll Out

The partial replacement of Portland clinker by supplementary cementitious materials (SCM) is one of the most popular and effective measures to reduce both costs and CO2 emissions related to cement production. An estimated 800 Mt/y of blast furnace slags, fly ashes and other materials are currently being used as SCM, but still the cement industry accounts for 5-8% of global CO2 emissions. If no further actions are taken, by the year 2050 this share might even rise beyond 25%. There is thus a clear challenge as to how emissions will be kept at bay and sustainability targets set by international commitments and policy documents will be met.Part of the solution will be a further roll-out of blended cements in which SCMs constitute the main part of the binder to which activators such as Portland cement are added. Since supply concerns are being raised for conventional high-quality SCMs it is clear that new materials and beneficiation technologies will need to step in to achieve further progress. This paper presents opportunities and challenges for new SCMs and demonstrates how advances towards more powerful and reliable characterisation techniques help to better understand and exploit SCM reactivity.

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Synthesis and Characterization of a Hybrid Cement Based on Fly Ash, Metakaolin and Portland Cement Clinker

Materials ◽

10.3390/ma13051084 ◽

2020 ◽

Vol 13 (5) ◽

pp. 1084 ◽

Cited By ~ 3

Author(s):

Adriagni C. Barboza-Chavez ◽

Lauren Y. Gómez-Zamorano ◽

Jorge L. Acevedo-Dávila

Keyword(s):

Fly Ash ◽

Portland Cement ◽

Ordinary Portland Cement ◽

Cementitious Materials ◽

Cement Industry ◽

Supplementary Cementitious Materials ◽

Cement Clinker ◽

Dense Matrix ◽

X Ray ◽

Reduction Of Co2

Hybrid cement has become one of the most viable options in the reduction of CO2 emissions to the environment that are generated by the cement industry. This could be explained by the reduction of the content of clinker in the final mixture and substitution of the remaining percentage with supplementary cementitious materials with the help of an alkaline activation. Following that, properties that are provided by an Ordinary Portland Cement and of a geopolymer are mixed in this type of hybrid material and could be achieved at room temperature. Thereafter, the main objective of this research was to synthesize hybrid cements reducing the clinker content of Portland Cement up to 20% and use metakaolin and fly ash as supplementary cementitious materials in different proportions. The mixtures were alkaline activated with a mixture of sodium silicate and sodium hydroxide, calculating the amounts according to the percentage of Na2O that is present in each of the activators. The samples were then characterized using Compressive strength, X-ray diffraction, Fourier Transform Infrared Spectroscopy, and Scanning Electron Microscopy with energy-dispersive X-ray spectroscopy. The results indicated that the hybrid cements have similar mechanical properties than an Ordinary Portland Cement, and they resulted in a dense matrix of hydration products similar to those that are generated by cements and geopolymers.

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Estimating CO2 Emission Savings from Ultrahigh Performance Concrete: A System Dynamics Approach

Materials ◽

10.3390/ma14040995 ◽

2021 ◽

Vol 14 (4) ◽

pp. 995

Author(s):

Mubashar Sheheryar ◽

Rashid Rehan ◽

Moncef L. Nehdi

Keyword(s):

System Dynamics ◽

Co2 Emissions ◽

New Technologies ◽

Cementitious Materials ◽

Supplementary Cementitious Materials ◽

Civil Infrastructure ◽

Portland Cement Concrete ◽

Flexible Framework ◽

Cement And Concrete

Ordinary Portland cement concrete (OPC) is the world’s most consumed commodity after water. However, the production of cement is a major contributor to global anthropogenic CO2 emissions. In recent years, ultrahigh performance concrete (UHPC) has emerged as a strong contender to replace OPC in diverse applications. UHPC has much higher mechanical strength, and thus less material is used in a structural member to resist the same load. Moreover, it has a much longer service life, reducing the long-term need for repair and replacement of aging civil infrastructure. Thus, UHPC can enhance the sustainability of cement and concrete. However, there is currently no robust tool to estimate the sustainability benefits of UHPC. This task is challenging considering that such benefits can only be captured over the long-term since variables, such as population growth and cement demand per capita, become more uncertain. In addition, the problem of CO2 emissions from cement and concrete is a complex system affected by time-dependent feedback. The System Dynamics (SD) method has specifically been developed for modeling such complex systems. Accordingly, a SD model was developed in this study to test various pertinent policy scenarios. It is shown that UHPC can reduce cumulative CO2 emissions of cement and concrete—over the studied simulation period—by more than 17%. If supplementary cementitious materials are further deployed in UHPC and new technologies permit reducing the carbon footprint per unit mass of cement, emission savings can become more substantial. The model offers a flexible framework where the user controls various inputs and can extend the model to account for new data, without the need for reconstruction of the entire model.

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Use of Potabilized Water Sludge in the Production of Low-Energy Blended Calcium Sulfoaluminate Cements

Applied Sciences ◽

10.3390/app11041679 ◽

2021 ◽

Vol 11 (4) ◽

pp. 1679

Author(s):

Antonio Telesca ◽

Neluta Ibris ◽

Milena Marroccoli

Keyword(s):

Co2 Emissions ◽

Carbon Footprint ◽

Energy Demand ◽

Cementitious Materials ◽

Supplementary Cementitious Materials ◽

X Ray Diffraction ◽

Hydration Properties ◽

Blended Cements ◽

Calcium Sulfoaluminate ◽

Pozzolanic Material

Ordinary Portland cement (OPC) manufacture determines about 8% of the global anthropogenic CO2 emissions. This has led to both the cement producers and the scientific community to develop new cementitious materials with a reduced carbon footprint. Calcium sulfoaluminate (CSA) cements are special hydraulic binders from non-Portland clinkers; they represent an important alternative to OPC due to their peculiar composition and significantly lower impact on the environment. CSA cements contain less limestone and require lower synthesis temperatures, which means a reduced kiln thermal energy demand and lower CO2 emissions. CSA cements can also be mixed with supplementary cementitious materials (SCMs) which further reduce the carbon footprint. This article was aimed at evaluating the possibility of using different amounts (20 and 35% by mass) of water potabilization sludges (WPSs) as SCM in CSA-blended cements. WPSs were treated thermally (TT) at 700° in order to obtain an industrial pozzolanic material. The hydration properties and the technical behavior of two different CSA-blended cements were investigated using differential thermal–thermogravimetric and X-ray diffraction analyses, mercury intrusion porosimetry, shrinkage/expansion and compressive strength measurements. The results showed that CSA binders containing 20% by mass of TTWPSs exhibited technological properties similar to those relating to plain CSA cement and were characterized by more pronounced eco-friendly features.

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Effect of ground granulated blast funrnace slag and fly ash on strength, permeability, and under-water abrasion of fine-grained concrete

Transport and Communication Science Journal ◽

10.25073/tcsj.71.7.4 ◽

2020 ◽

Vol 71 (7) ◽

pp. 775-788

Author(s):

Quyet Truong Van ◽

Sang Nguyen Thanh

Keyword(s):

Fly Ash ◽

Concrete Strength ◽

Cementitious Materials ◽

Supplementary Cementitious Materials ◽

Chloride Permeability ◽

Cement Replacement ◽

Fine Grained ◽

Granulated Blast Furnace Slag ◽

Compressive Strength Test ◽

Economic Ground

The utilisation of supplementary cementitious materials (SCMs) is widespread in the concrete industry because of the performance benefits and economic. Ground granulated blast furnace slag (GGBFS) and fly ash (FA) have been used as the SCMs in concrete for reducing the weight of cement and improving durability properties. In this study, GGBFS at different cement replacement ratios of 0%, 20%, 40% and 60% by weight were used in fine-grained concrete. The ternary binders containing GGBFS and FA at cement replacement ratio of 60% by weight have also evaluated. Flexural and compressive strength test, rapid chloride permeability test and under-water abrasion test were performed. Experimental results show that the increase in concrete strength with GGBFS contents from 20% to 40% but at a higher period of maturity (56 days and more). The chloride permeability the under-water abrasion reduced with the increasing cement replacement by GGBFS or a combination of GGBFS and FA

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