scholarly journals Reduced Carbonation, Sulfate and Chloride Ingress Due to the Substitution of Cement by 10% Non-Precalcined Bentonite

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1300
Author(s):  
Carmen Andrade ◽  
Ana Martínez-Serrano ◽  
Miguel Ángel Sanjuán ◽  
José Antonio Tenorio Ríos
Keyword(s):  
Portland Cement ◽  
Cement Industry ◽  
Chloride Ingress ◽  
Gas Emissions ◽  
Nineteen Seventies ◽  
Novel Approach ◽  
Carbonation Resistance ◽  
Structural Applications ◽  
Mineral Additions ◽  
Clinker Production

The Portland cement industry is presently deemed to account for around 7.4% of the carbon dioxide emitted annually worldwide. Clinker production is being reduced worldwide in response to the need to drastically lower greenhouse gas emissions. The trend began in the nineteen seventies with the advent of mineral additions to replace clinker. Blast furnace slag and fly ash, industrial by-products that were being stockpiled in waste heaps at the time, have not commonly been included in cements. Supply of these additions is no longer guaranteed, however, due to restrained activity in the source industries for the same reasons as in clinker production. The search is consequently on for other additions that may lower pollutant gas emissions without altering cement performance. In this study, bentonite, a very common clay, was used as such an addition directly, with no need for precalcination, a still novel approach that has been scantly explored to date for reinforced structural concrete with structural applications. The results of the mechanical strength and chemical resistance (to sulfates, carbonation and chlorides) tests conducted are promising. The carbonation findings proved to be of particular interest, for that is the area where cement with mineral additions tends to be least effective. In the bentonite-bearing material analysed here, however, carbonation resistance was found to be as low as or lower than that observed in plain Portland cement.

scholarly journals Decrease of Carbonation, Sulfate and Chloride Ingress due to the Substitution of Cement by 10% of Non Calcined Bentonite

2021 ◽  
Author(s):  
Carmen Andrade ◽  
Ana Martínez-Serrano ◽  
Miguel Ángel Sanjuán ◽  
José Antonio Tenorio Ríos
Keyword(s):  
Chloride Ingress ◽  
Gas Emissions ◽  
Nineteen Seventies ◽  
Novel Approach ◽  
Carbonation Resistance ◽  
Structural Applications ◽  
Mineral Additions ◽  
Clinker Production ◽  
Furnace Slag ◽  
By Products

Clinker production is being reduced worldwide in response to the need to drastically lower greenhouse gas emissions. The trend began in the nineteen seventies with the advent of mineral additions to replace clinker. Blast furnace slag and fly ash, industrial by-products that were being stockpiled in waste heaps at the time, have not commonly been included in cements. Supply of these additions is no longer guaranteed, however, due to restrained activity in the source industries for the same reasons as in clinker production. The search is consequently on for other additions that may lower pollutant gas emissions without altering cement performance. In this research bentonite, a very common clay, was used as such an addition directly, with no need for pre-calcination, an still novel approach that has gone little explored to date for reinforced concrete with structural applications. The results of the mechanical strength and chemical resistance (to sulfates, carbonation and chlorides) tests conducted are promising. The carbonation findings proved to be of particular interest, for that is the area where cement with mineral additions tend to be least effective. In the bentonite-bearing material analysed here, however, carbonation resistance was found to be low as or lower than observed in plain Portland cement.

scholarly journals Utilization of Iron Ore Tailings as Raw Material for Portland Cement Clinker Production

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
Li Luo ◽  
Yimin Zhang ◽  
Shenxu Bao ◽  
Tiejun Chen
Keyword(s):  
Portland Cement ◽  
Iron Ore ◽  
Mechanical Performance ◽  
Mineralogical Composition ◽  
Cement Industry ◽  
Raw Material ◽  
Cement Clinker ◽  
Iron Ore Tailings ◽  
Portland Cement Clinker ◽  
Clinker Production

The cement industry has for some time been seeking alternative raw material for the Portland cement clinker production. The aim of this research was to investigate the possibility of utilizing iron ore tailings (IOT) to replace clay as alumina-silicate raw material for the production of Portland cement clinker. For this purpose, two kinds of clinkers were prepared: one was prepared by IOT; the other was prepared by clay as a reference. The reactivity and burnability of raw meal, mineralogical composition and physical properties of clinker, and hydration characteristic of cement were studied by burnability analysis, differential thermal analysis, X-ray diffraction, and hydration analysis. The results showed that the raw meal containing IOT had higher reactivity and burnability than the raw meal containing clay, and the use of IOT did not affect the formation of characteristic mineralogical phases of Portland cement clinker. Furthermore, the physical and mechanical performance of two cement clinkers were similar. In addition, the use of IOT was found to improve the grindability of clinker and lower the hydration heat of Portland cement. These findings suggest that IOT can replace the clay as alumina-silicate raw material for the preparation of Portland cement clinker.

scholarly journals Effects of Red Mud Addition in the Microstructure, Durability and Mechanical Performance of Cement Mortars

2019 ◽  
Vol 9 (5) ◽  
pp. 984 ◽  
Author(s):  
José Ortega ◽  
Marta Cabeza ◽  
Antonio Tenza-Abril ◽  
Teresa Real-Herraiz ◽  
Miguel Climent ◽  
...  
Keyword(s):  
Portland Cement ◽  
Red Mud ◽  
Mechanical Performance ◽  
Network Evolution ◽  
Cement Industry ◽  
Pozzolanic Activity ◽  
Great Effort ◽  
Chloride Ingress ◽  
Cement Mortars ◽  
Cement Based Materials

Recently, there has been a great effort to incorporate industrial waste into cement-based materials to reach a more sustainable cement industry. In this regard, the Bayer process of obtaining alumina from bauxite generates huge amounts of waste called red mud. Few research articles have pointed out the possibility that red mud has pozzolanic activity. In view of that, the objective of this research is to analyse the short-term effects in the pore structure, mechanical performance and durability of mortars which incorporate up to 20% of red mud as a clinker replacement. As a reference, ordinary Portland cement and fly ash Portland cement mortars were also studied. The microstructure was characterised through mercury intrusion porosimetry and non-destructive impedance spectroscopy, which has not previously been used for studying the pore network evolution of red mud cement-based materials. The possible pozzolanic activity of red mud has been checked using differential scanning calorimetry. The non-steady state chloride migration coefficient and the mechanical properties were studied too. According to the results obtained, the addition of red mud entailed a greater microstructure refinement of the mortar, did not worsen the resistance against chloride ingress and reduced the compressive strength compared to control binders.

Sericitic Phyllite as Addition in Portland Cement

2018 ◽  
Vol 930 ◽  
pp. 131-136 ◽  
Author(s):  
Isabella de Souza Morais ◽  
Luciano Fernandes de Magalhães ◽  
Luis Felipe dos Santos Lara ◽  
Elaine Carballo Siqueira Corrêa ◽  
Raquel Maria Rocha Oliveira Menezes ◽  
...  
Keyword(s):  
Portland Cement ◽  
High Performance ◽  
Planetary Mill ◽  
Cement Industry ◽  
Partial Substitution ◽  
Electric Resistance Furnace ◽  
Mineral Addition ◽  
Mineral Additions ◽  
Different Temperatures ◽  
Pozzolanic Properties

Pozzolans are materials that when milled are able to react with the cement, forming compounds with binder properties. Seeking to reduce costs and improve Portland cement performance, the cement industry has used mineral additions such as pozzolans, partially replacing clinker in Portland cement. Sericitic Phyllite is a metamorphic rock, considered sterile by iron mining. It is extracted from the pit to enable the extraction of iron ore and is disposed in sterile piles, representing an environmental liability. The present work evaluated the possibility of the Sericitic Phyllite acquires pozzolanic properties from thermal treatment, to be used as mineral addition in the partial substitution of Portland cement in mortars. The material was processed by milling in its natural moisture of 8% using a high performance planetary mill, and calcination in an electric resistance furnace at different temperatures (350, 550 and 850oC) for thirty minutes each. It was characterized by laser granulometry, X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal and thermogravimetric analysis (DTA/TGA). After characterization, specimens were prepared with 25% substitution by weight of the Portland cement by the Sericitic Phyllite. The calcined material in 350, 550 and 850oC reached, respectively, 70%, 76% and 82% of the resistance of the control mortar. The results indicate the feasibility of using the Sericitic Phyllite as mineral addition in Portland cements as the mortars with the calcined material in all temperatures reached 32MPa.

scholarly journals Carbonation Resistance of High Volume Fly Ash Concrete

2014 ◽  
Vol 634 ◽  
pp. 288-299 ◽  
Author(s):  
Rui Reis ◽  
Raphaele Malheiro ◽  
Aires Camões ◽  
Manuel Ribeiro
Keyword(s):  
Fly Ash ◽  
Energy Use ◽  
High Volume ◽  
Hydrated Lime ◽  
Cement Industry ◽  
Concrete Carbonation ◽  
Carbonation Resistance ◽  
Industrial Energy ◽  
Mineral Additions ◽  
Industrial Energy Use

The cement industry is responsible for a large part of the global environmental problems: is the largest consumer of natural resources; the most responsible for the emission of greenhouse gases, including about 1.8 Gt of CO2; and requires huge amounts of energy, corresponding to between 12 and 15% of industrial energy use. The cement is also not used in the most appropriate manner, since 40% of the consumption of concrete is due to the renovation and repair of buildings, making concrete structures inefficient because its durability is relatively low. However, in the future, concrete can and should evolve in order to improve its eco-efficiency, with a smaller amount of cement in its composition, replacing it with high quantities of mineral additions, particularly fly ash. Nevertheless, current technology may not allow this type of concrete to be very efficient, because its long-term durability may be compromised. In fact, with increasing dosage of pozzolanic mineral additions, alkali paste components are consumed in the reaction leaving it vulnerable to concrete carbonation which may compromise the passivation layer needed for steel rebar protection against corrosion. This article explores a promising approach to mitigate this problem, which consists in the careful addition of hydrated lime in the concrete composition, highlighting the synergy of its components, significantly enhancing its carbonation resistance. It is proposed, therefore, to manufacture a concrete with high volume of fly ash, low cement content and high service life period: an efficient and sustainable concrete. In this context, an experimental campaign was developed with the aim of characterization of pastes behavior with high fly ash content, in particular with respect to its durability. The results will be presented and properly analyzed.

scholarly journals Life Cycle Assessment of Ordinary Portland Cement (OPC) Using both Problem Oriented (Midpoint) Approach and Damage Oriented Approach (Endpoint)

2021 ◽  
Author(s):  
Busola D. Olagunju ◽  
Oludolapo A. Olanrewaju
Keyword(s):  
Global Warming ◽  
Life Cycle Assessment ◽  
Life Cycle ◽  
Environmental Impact ◽  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Cement Industry ◽  
The World ◽  
Clinker Production ◽  
Oriented Approach

The concern for environmental related impacts of the cement industry is fast growing in recent times. The industry is challenged with high environmental impact which spans through the entire production process. Life cycle assessment (LCA) evaluates the environmental impact of product or process throughout the cycle of production. This can be done using either or both midpoint (process-oriented) and endpoint (damage-oriented) approaches of life cycle impact assessment (LCIA). This study assessed the environmental impact of 1 kg Ordinary Portland Cement (OPC) using both approaches of LCIA. This analysis was carried out using a data modeled after the rest of the world other than China, India, Europe, US and Switzerland. The dataset was taken from Ecoinvent database incorporated in the SimaPro 9.0.49 software. The result of the analysis showed that clinker production phase produced the highest impact and CO2 is the highest pollutant emitter at both endpoint and midpoint approaches. This is responsible for global warming known to affect both human health and the ecosystem. Also, toxicity in form of emission of high copper affects the ecosystem as well as humans. In addition, high fossil resources (crude oil) are consumed and pose the possibility for scarcity.

The Portland Cement Industry of the World

1898 ◽  
Vol 46 (1192supp) ◽  
pp. 19108-19109
Author(s):  
Bernard L. Green
Keyword(s):  
Portland Cement ◽  
Cement Industry ◽  
The World

Utilization of petroleum sludge wastes for increasing productivity of ordinary portland cement

2021 ◽  
Vol 19 (4) ◽  
pp. 315-328
Author(s):  
N.M. Khalil ◽  
Yousif Algamal
Keyword(s):  
Portland Cement ◽  
Ordinary Portland Cement ◽  
Production Capacity ◽  
Hydration Product ◽  
High Energy ◽  
Cement Industry ◽  
Blended Cements ◽  
Petroleum Waste ◽  
Waste Sludge ◽  
Suitable Amount

This work aims at maximum exploitation of petroleum waste sludge as additive to portland cement to prepare blended cements and hence increasing its production capacity without further firing. This will decrease the main cement industry problems involving environmental pollution such as releasing gases and high-energy consumption during industry and hence maximizes the production economics. Six batches of ordinary portland cement (OPC) mixed with different proportions of petroleum waste sludge (PWS) donated as C1 (control batch contains no PWS), C2 (contains 90 wt.% of OPC+10 wt.% of PWS), C3 (contains 80 wt.% of OPC+20 wt.% of PWS), C4 (contains 70 wt.% of OPC+30 wt.% of PWS), C4 (contains 60 wt.% of OPC+40 wt.% of PWS) and C6 (contains 50 wt.% of OPC+50 wt.% of PWS), were prepared and mixed individually with the suitable amount of mixing water. Cement mixes C2, C3 and C4 showed improved cementing and physicomechanical properties compared with pure cement (C1) with special concern of mix C4. Such improvement is due to the relatively higher surface area as well as the high content of kaolinite and quartz in the added PWS (high pozzalanity) favoring the hydration process evidenced by the increase in the cement hydration product (portlandite mineral (Ca (OH) 2).

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