scholarly journals Activated Clays and Their Potential in the Cement Industry

2021 ◽  
Author(s):  
Carlos Hernando Aramburo Varela ◽  
Luiz Felipe de Pinho ◽  
César Pedrajas Nieto-Márquez ◽  
Rafael Talero Morales
Keyword(s):  
Portland Cement ◽  
Thermal Activation ◽  
Large Scale ◽  
Scientific Basis ◽  
Cementitious Material ◽  
Cement Industry ◽  
Supplementary Cementitious Material ◽  
Cement Manufacture ◽  
Reactive Alumina ◽  
Reactive Silica

The thermal activation of clays to produce highly reactive artificial pozzolans on a large scale is one of the most important technologies developed on an industrial scale to reduce CO2 emissions in cement manufacture. This technical document deals with the scientific basis for the thermal activation of clays to produce an extraordinarily high quality supplementary cementitious material (SCM) based on the contents of its hydraulic factors, reactive silica (SiO2r–) and reactive alumina (Al2O3r–). The production process and the optimization of its use in the new cements offers better performance, features and durability. Furthermore, its mixture with Portland cement is much more appropriate when carried out in a blending station after both components, activated clay and Portland cement, are ground separately and not jointly in a single mill.

Research on the Calculation Method for Cement Manufacture Carbon Footprint

2013 ◽  
Vol 368-370 ◽  
pp. 968-975 ◽  
Author(s):  
Yu Feng Gan ◽  
Xian Ming Qin ◽  
Hong Guo
Keyword(s):  
Carbon Footprint ◽  
Calculation Method ◽  
Manufacturing Process ◽  
Scientific Basis ◽  
Calculation Model ◽  
Cement Industry ◽  
Fujian Province ◽  
Calculation Process ◽  
Cement Manufacture

To form a carbon footprint calculation method for cement manufacture, a detail analysis is conducted on the essential factors of the manufacturing process of the cement industry in Fujian Province. From the analysis result, the calculation model and calculation process for cement manufacture carbon footprint is formed to provide a scientific basis for the carbon footprint calculation.

Bétons à haute performance à base de ciments composés contenant du laitier et de la fumée de silice

2003 ◽  
Vol 30 (2) ◽  
pp. 414-428 ◽  
Author(s):  
Mladenka Saric-Coric ◽  
Pierre-Claude Aïtcin
Keyword(s):  
Sustainable Development ◽  
Compressive Strength ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Cementitious Material ◽  
Cement Industry ◽  
Supplementary Cementitious Material ◽  
Cement Replacement ◽  
Furnace Slag ◽  
Scaling Resistance

For each tonne of cement used, the cement industry emits an average of 0.9 t of CO2, which contributes to the greenhouse effect. To satisfy the demands of the concrete industry for cementing materials, new environmental requirements, and the implementation of a sustainable development policy, the use of supplementary cementitious material as a replacement of part of the Portland cement has proven to be an interesting avenue that has not yet been fully explored. Granulated blast-furnace slag has been and is being used as a supplementary cementitious material in replacement of cement in many countries. In Canada, its proportion is usually limited to 20-25% of cement replacement owing to a significant decrease in early age compressive strength as well as a lower scaling resistance. In this study, we have tried to show that by reducing the water:cement ratio we can increase cement replacement by slag up to 50% without harming its short-term compressive strength and scaling resistance. The concretes that were prepared had a workability comparable to that of the reference concrete without slag, sufficient compressive strength to allow demoulding after 24 h, very low chloride ion permeability even at 28 d, as well as very good freeze-thaw and scaling resistance, as long as it is water-cured for a slightly longer period.Key words: high-performance concrete, blast-furnace slag, sustainable development, superplasticizers, workability, durability, silica fume.

scholarly journals Metal magnesium industry waste for partial replacement of Portland cement

2020 ◽  
Vol 13 (6) ◽  
Author(s):  
Maysa Lorena Figueiredo Martins ◽  
Richard Rodrigues Barreto ◽  
Paulo Roberto Ribeiro Soares Junior ◽  
Ivete Peixoto Pinheiro ◽  
Augusto Cesar da Silva Bezerra
Keyword(s):  
Portland Cement ◽  
Mineralogical Composition ◽  
High Energy ◽  
Cement Industry ◽  
Cement Clinker ◽  
Partial Replacement ◽  
Supplementary Cementitious Material ◽  
X Ray ◽  
Industry Waste ◽  
Energy Demands

ABSTRACT: The high demand for concrete has triggered studies on the mitigation of Portland cement production impacts, such as greenhouse gas emissions and energy demands, in addition to enabling cost reduction. Partial replacement of cement with other materials has been employed as an alternative to minimize the damage caused by the cement industry. In this regard, it is necessary to use materials that efficiently replace cement clinker. This study uses waste generated from the production of metallic magnesium as a partial replacement for Portland cement. The substitution is aimed at reducing the amount of clinker used, as its production necessitates high energy consumption and results in emission of large quantities of CO2 into the atmosphere. The tailings were characterized via X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and granulometric analysis. For evaluating the mechanical behavior and porosity, 25% of the cement (by mass) was replaced with tailings, and the resulting composite was molded into cylindrical specimens. After curing for 28 and 91 days, all specimens underwent compression testing. The results of the physical characterization showed that more than 65% of the tailing grain was lesser than 45 μm in size, which contributes to the packaging effect. In terms of the chemical and mineralogical composition, the tailing had high levels of calcium, and the predominant phases could be identified. The compressive strength of the mortar with substitution was higher than 40 MPa. The convergence observed between the results of the different characterization techniques demonstrates the efficiency of using the waste as a supplementary cementitious material.

scholarly journals Use of metakaolin as supplementary cementitious material in concrete, with focus on durability properties

2019 ◽  
Vol 4 ◽  
pp. 89-102 ◽  
Author(s):  
Alice T Bakera ◽  
Mark G Alexander
Keyword(s):  
Portland Cement ◽  
Cementitious Material ◽  
Concrete Durability ◽  
Western Cape ◽  
Supplementary Cementitious Material ◽  
Durability Properties ◽  
Carbonation Resistance ◽  
Performance Results ◽  
Local Materials ◽  
Durability Performance

Numerous research efforts on metakaolin as a supplementary cementitious material (SCM) have been undertaken in the past 20 years. This material, while relatively expensive mainly due to low production volumes worldwide, nevertheless has a significantly lower production cost than Portland cement. However, industry remains tentative in considering metakaolin in concrete. This paper takes the view that industry should consider investing in the production and application of metakaolin in appropriate concrete projects, particularly in aggressive environments where plain Portland cement may be inadequate, and where other SCMs may not readily be available. The main contribution of the paper is a global review of recent studies on the use of metakaolin in different types of concrete. This international experience is then compared with results from a study on the durability performance of metakaolin concrete using local materials in the Western Cape province of South Africa, as a means of concrete performance improvement. The study investigates concrete durability properties: penetrability (sorptivity, permeability, conductivity and diffusion), mitigation of Alkali-Silica Reaction (ASR), and carbonation resistance. The concretes were prepared with three water-binder ratios (0.4, 0.5 and 0.6), and with metakaolin replacement levels of 0% (control), 10%, 15% and 20%. Performance results show that, with increasing metakaolin content, the transport properties of concrete are considerably improved, ASR expansion due to a highly reactive local aggregate decreases to non-deleterious levels, while no detrimental effect on carbonation is observed. Thus, metakaolin could serve as a valuable SCM to enhance the durability performance of concrete in local aggressive environments.

scholarly journals CO2 mineralization of demolished concrete wastes into a supplementary cementitious material – a new CCU approach for the cement industry

2021 ◽  
Vol 6 ◽  
pp. 53-60
Author(s):  
Maciej Zajac ◽  
Jan Skocek ◽  
Jørgen Skibsted ◽  
Mohsen Ben Haha
Keyword(s):  
Silica Gel ◽  
Cement Paste ◽  
Cementitious Material ◽  
Cement Industry ◽  
Recycled Concrete ◽  
Recycled Aggregates ◽  
Supplementary Cementitious Material ◽  
Co2 Mineralization ◽  
Concrete Recycling ◽  
Composite Cements

This contribution discusses the carbon capture and utilization (CCU) approach based on CO2 mineralization of cement paste from recycled concrete as new approach to capture CO2 and significantly contribute to the reduction in CO2 emissions associated with cement production. The current literature suggests that all CO2 released from the decomposition of limestone during clinker production can be sequestered by carbonation of the end-of-life cement paste. This carbonation can be achieved in a few hours at ambient temperature and pressure and with a relatively low CO2 concentration (< 10 %) in the gas. The carbonation of cement paste produces calcite and an amorphous alumina-silica gel, the latter being a pozzolanic material that can be utilized as a supplementary cementitious material. The pozzolanic reaction of the alumina-silica gel is very rapid as a result of its high specific surface and amorphous structure. Thus, composite cements containing carbonated cement paste are characterized by a rapid strength gain. The successful implementation of this CCU approach relies also on improved concrete recycling techniques and methods currently under development to separate out the cement paste fines and such. Full concrete recycling will further improve the circular utilization of cement and concrete by using recycled aggregates instead of natural deposits of aggregates.  Although the feasibility of the process has already been demonstrated at the industrial scale, there are still several open questions related to optimum carbonation conditions and the performance of carbonated material in novel composite cements.

scholarly journals Copper Slag Blended Cement: An Environmental Sustainable Approach for Cement Industry in India

2016 ◽  
Vol 11 (1) ◽  
pp. 186-196
Author(s):  
Jagmeet Singh ◽  
Jaspal Singh ◽  
Manpreet Kaur
Keyword(s):  
Blended Cement ◽  
Copper Slag ◽  
Cementitious Materials ◽  
Strength Test ◽  
Cementitious Material ◽  
Cement Industry ◽  
Supplementary Cementitious Materials ◽  
Material Strength ◽  
Test Results ◽  
Supplementary Cementitious Material

Indian cement industry is facing environmental issue of emission of carbon dioxide (CO2), a greenhouse gas. Blended cements including supplementary cementitious materials are substitute of Portland cement to reduce CO2 emission. The present paper investigates theappropriateness of copper slag (CS) as supplementary cementitious material. Strength properties and hydration of mixes were determined at different replacement levels of CS with cement. Compressive, flexural and tensile strength of each mix was found out at different curing periods. The hydration of cement was investigated through X-ray diffraction (XRD). The strength test results showed that substitution of up to 20% of CS can significantly replace Portland cement.XRD test results were corresponding to strength test results. The present study encourages the utilization of CS as supplementary cementitious material to make economical and environmentally sustainable blended cement

Rock Wool Waste as Supplementary Cementitious Material for Portland Cement-Based Composites

2018 ◽  
Author(s):  
K. D. C. Silva ◽  
G. C. Silva ◽  
J. F. Natalli ◽  
J. C. Mendes ◽  
G. J. B. Silva ◽  
...  
Keyword(s):  
Portland Cement ◽  
Cementitious Material ◽  
Supplementary Cementitious Material ◽  
Rock Wool
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