Environmental sustainability in cement industry: An integrated approach for green and economical cement production

Poudyal, Lochana; Adhikari, Kushal

doi:10.1016/j.resenv.2021.100024

Cited by 88 publications

(57 citation statements)

References 23 publications

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“…The production of Ordinary Portland Cement (OPC) involves: (i) very high temperatures, usually above 1450 • C, consequently an enormous energy consumption [1][2][3]; (ii) the utilization of large quantities of non-renewable natural raw materials [1,3], mostly limestone and dolomite (as calcium sources) and marls, clays or shale (as silica and alumina sources) [1]; (iii) generation of particulate material [1,3], starting in mining process [1]; and (iv) significant CO 2 emissions [1][2][3][4][5][6]. Being mostly generated on the calcination (decomposition of limestone) [1,2,6] but also from the consumption of electricity (air coolers and ball mills) [1,2] and fossil fuels (preheater, calciner and kiln) [1,2,6].…”

Section: Introductionmentioning

confidence: 99%

“…Being mostly generated on the calcination (decomposition of limestone) [1,2,6] but also from the consumption of electricity (air coolers and ball mills) [1,2] and fossil fuels (preheater, calciner and kiln) [1,2,6]. Worldwide those emissions are around 8 to 10% of the anthropogenic global CO 2 emissions, and it is expected to grow [5]. To limit the rise in global temperatures this century to less than 2 • C above preindustrial levels the International Energy Agency has issued a technology roadmap for reducing CO 2 emissions in the cement industry through 2050 [7].…”

Section: Introductionmentioning

confidence: 99%

“…The substitution of OPC by supplementary cementitious materials, especially byproducts or wastes of distinct industrial processes, in the formulation of cement-based products might be a way to reduce its environmental footprint. Nowadays, one of the main supplementary cementitious materials used is siliceous fly ash (FA) [5,8], fundamentally because of its pozzolanic reactivity, which is a by-product of coal combustion in electric and thermal-electric power stations for heat and power production [8]. The pozzolanic reactivity is the ability that the material has to react, at ambient temperature, with the clinker hydration by-product Ca(OH) 2 forming compounds with binding potential [9].…”

Section: Introductionmentioning

confidence: 99%

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Development of a Commercial Screed Mortar with Low OPC Content by Incorporation of Biomass Fly Ash

et al. 2021

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Substitute Ordinary Portland Cement (OPC) by biomass fly ash (BFA) reduce the environmental impact produced by cement-based materials, and at the same time, decreased the economic and environmental burden associated with the landfilling of this waste. This study aims to evaluate the recycling of BFA as supplementary cementitious materials (SCMs) in a commercial screed mortar formulation. Two BFA varieties, both resulting from fluidized bed combustion of forest residues, were used to replace 17, 50, and 67 wt.% of OPC. The influence of simple pre-treatment processes of the BFA, such as sieving and grinding, in the fresh and hardened state properties of the mortars, was evaluated. The BFAs were characterized in terms of chemical (XRF) and mineralogical (XRD) composition, particle size distribution (laser diffraction-COULTER) and morphology (SEM). The prepared formulations were characterized in terms of workability, mass loss upon curing, bulk density, sorptivity (by immersion and capillary), flexural and compressive strength and durability to 25 freeze–thaw cycles. Both of the BFAs are potential SCMs. Substitution of 17 wt.% OPC with BFA complied with the product technical requirements for compressive and flexural strength (10 and 3 MPa, respectively), with the ground and sieved and just sieved BFAs perform slightly better than the as-received BFA.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Development of a Commercial Screed Mortar with Low OPC Content by Incorporation of Biomass Fly Ash

et al. 2021

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“…During the cement production process, large amounts of carbon dioxide are emitted. The cement industry alone accounts for approximately 4.1% of the EU’s and around 8 to 10% of world’s anthropogenic CO 2 emissions [ 1 ]. Carbon dioxide in cement production is emitted in two primary ways: the calcination of calcium carbonate and fuel combustion in the cement kiln as well as in two indirect ways: electrical energy consumption for running the process equipment in the cement plant and for the transportation of raw materials and cement [ 2 , 3 ].…”

Section: Introductionmentioning

confidence: 99%

Alkali-Activated Mortars with Recycled Fines and Hemp as a Sand

Pawluczuk

Kalinowska-Wichrowska

Soomro

2021

Materials

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Nowadays, effective and eco-friendly ways of using waste materials that could replace natural resources (for example, sand) in the production of concrete composites are highly sought. The article presents the results of research on geopolymer composites produced from two types of waste materials—hemp and fine fractions recovered from recycled cement concrete, which were both used as a replacement for standard sand. A total of two research experiments were conducted. In the first experiment, geopolymer mortars were made using the standard sand, which was substituted with recycled fines, from 0% to 30% by weight. In the second study, geopolymers containing organic filler were designed, where the variables were (i) the amount of hemp and the percent of sand by volume (0%, 2.5%, and 5%) and(ii) the amount of hydrated lime and the percent of fly ash (by weight) (0%, 2%, and 4%) that were prepared. In both cases, the basic properties of the prepared composites were determined, including their flexural strength, compressive strength, volume density in a dry and saturated state, and water absorption by weight. Observations of the microstructure of the geopolymers using an electron and optical microscope were also conducted. The test results show that both materials (hemp and recycled fines) and the appropriate selection of the proportions of mortar components and can produce composites with better physical and mechanical properties compared to mortars made of only natural sand. The detailed results show that recycled fines (RF) can be a valuable substitute for natural sand. The presence of 30% recycled fines (by weight) as a replacement for natural sand in the alkali-activated mortar increased its compressive strength by 26% and its flexural strength by 9% compared to control composites (compared to composites made entirely of sand without its alternatives). The good dispersion of both materials in the geopolymer matrix probably contributed to filling of the pores and reducing the water absorption of the composites. The use of hemp as a sand substitute generally caused a decrease in the strength properties of geopolymer mortar, but satisfactory results were achieved with the substitution of 2.5% hemp (by volume) as a replacement for standard sand (40 MPa for compressive strength, and 6.3MPa for flexural strength). Both of these waste materials could be used as a substitute for natural sand and are examples of an eco-friendly and sustainable substitution to save natural, non-renewable resources.

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“…There is increasing demand for materials to replace Portland cement [ 3 , 4 ] because the OPC industry accounts for 8 to 10% of worldwide CO 2 emissions, accelerating global warming [ 5 ]. Therefore, many studies have been conducted on developing alternative binders with a low carbon footprint, using various industrial by-products, such as fly ash or ground-granulated blast-furnace slag (GGBFS) to replace OPC [ 6 , 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

Mechanical and Durability Properties of Cementless Concretes Made Using Three Types of CaO-Activated GGBFS Binders

Yum

Jeon

et al. 2021

Materials

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This study examined the mechanical and durability properties of CaO-activated ground-granulated blast-furnace slag (GGBFS) concretes made with three different additives (CaCl2, Ca(HCOO)2, and Ca(NO3)2) and compared their properties to the concrete made with 100% Ordinary Portland Cement (OPC). All concrete mixtures satisfied targeted air content and slump ranges but exhibited significantly different mechanical and durability properties. The CaO-activated GGBFS concretes showed different strength levels, depending on the type of additive. The added CaCl2 was the most effective, but Ca(NO3)2 was the least effective at increasing mechanical strength in the CaO-activated GGBFS system. The OPC concrete showed the most excellent freezing–thawing resistance in the durability test, but only the CaO-activated GGBFS concrete with CaCl2 exhibited relatively similar resistance. In addition, the chemical resistance was significantly dependent on the type of acid solution and the type of binder. The OPC concrete had the best resistance in the HCl solution, while all CaO-activated GGBFS concretes had relatively low resistances. However, in the H2SO4 solution, all CaO-activated GGBFS concretes had better resistance than the OPC concrete. All concrete with sulfate ions had ettringite before immersion. However, when they were immersed in HCl solution, ettringite tended to decrease, and gypsum was generated. Meanwhile, the CaO-activated GGBFS concrete with CaCl2 did not change the type of reaction product, possibly due to the absence of ettringite and Ca(OH)2. When immersed in an H2SO4 solution, ettringite decreased, and gypsum increased in all concrete. In addition, the CaO-activated concrete with CaCl2 had a considerable amount of gypsum; it seemed that the dissolved C-S-H and calcite, due to the low pH, likely produced Ca2+ ions, and gypsum formed from the reaction between Ca2+ and H2SO4.

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Environmental sustainability in cement industry: An integrated approach for green and economical cement production

Cited by 88 publications

References 23 publications

Development of a Commercial Screed Mortar with Low OPC Content by Incorporation of Biomass Fly Ash

Development of a Commercial Screed Mortar with Low OPC Content by Incorporation of Biomass Fly Ash

Alkali-Activated Mortars with Recycled Fines and Hemp as a Sand

Mechanical and Durability Properties of Cementless Concretes Made Using Three Types of CaO-Activated GGBFS Binders

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