World cement production and environmental implications

Uwasu, Michinori; Hara, Keishiro; Yabar, Helmut

doi:10.1016/j.envdev.2014.02.005

Cited by 90 publications

(32 citation statements)

References 22 publications

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“…cement produced approximately 0.82 tons of carbon dioxide are released into the atmosphere [3]. The significance is that approximately 5% of the world's anthropogenic carbon emissions can be traced to the production of cement [4]. However, it is because it is both financially and environmentally costly that reducing the proportion of cement in concrete mixtures has gained popularity for decades.…”

Section: Introductionmentioning

confidence: 99%

“…The second is the acceleration of the cement hydration, which Metakaolin is an aluminous and siliceous natural pozzolan that conforms to ASTM C618, and is the product of thermally or mechanically activating kaolin clay. Typically, kaolin clay that is used in the production of metakaolin contains a high percentage (40-70%) of the clay mineral kaolinite, Al 2 Si 2 O 5 (OH) 4 [11]. In its dehydroxylated form, metakaolin can be used in concrete to enhance mechanical properties and increase durability [12][13][14][15][16], while also improving the aesthetic appeal with its white color.…”

Section: Introductionmentioning

confidence: 99%

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Sustainable Materials for Transportation Infrastructures: Comparison of Three Commercially-Available Metakaolin Products in Binary Cementitious Systems

et al. 2018

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Abstract:Metakaolin is the only major natural pozzolan to be specified for use as a supplementary cementitious material in the United States. As a result, the metakaolin market for concrete has grown dramatically in the past 20 years. As of now, the specifications of up to 16 state departments of transportation allow for the use of commercially-available and high-reactivity metakaolin products. However, to the best of the authors' knowledge, no study has been performed to evaluate whether these products are comparable in their performance. Three commercially-available (U.S.) metakaolin products, each replacing 10%, 15%, and 20% of the cement content in concrete and mortar mixtures are studied. Concrete mixtures contained a cementitious content of 422 kg/m 3 , a coarse aggregate fraction of 985 kg/m 3 , and a water-to-cementitious ratio equal to 0.43. Varying levels of a superplasticizer were used to maintain a uniform workability between mixtures. Each mixture was subjected to the following tests: compression, split-cylinder tension, modulus of rupture, dynamic elastic modulus, rapid chloride-ion penetrability, alkali-silica reactivity, sulfate resistance, the coefficient of thermal expansion, and drying shrinkage. Benefits from the inclusion of metakaolin were highly product-dependent and include increases in mechanical strength. All metakaolin supplemented concrete mixtures benefitted from decreased permeability and increased resistance to chemical attacks, with the exception of the sulfate resistance of mortars including a metakaolin product with high fineness. The inclusion of any metakaolin at any replacement level increased the coefficient of thermal expansion of concrete specimens. Reasons for difference in performance between products are discussed, and predictors of quality are recommended.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Sustainable Materials for Transportation Infrastructures: Comparison of Three Commercially-Available Metakaolin Products in Binary Cementitious Systems

et al. 2018

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“…It is known that the annual worldwide production of ordinary Portland cement (OPC) is approaching 4 billion tonnes [1]. OPC is the most popular binder used in concrete for construction because of its durability, universality and relatively low cost.…”

Section: Introductionmentioning

confidence: 99%

Heat flow and strength properties of perspective hydraulic binder material

Šiaučiūnas

Gendvilas

Mikaliunaite

et al. 2015

J Therm Anal Calorim

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In this work, the results of preparing a novel hydraulic binder material on a-C 2 SH basis using both chemically pure and natural raw materials are presented, as well as hydration and strength properties of such binders are described. a-C 2 SH was hydrothermally synthesized at 200°C for 8 h from reagents (CaO, SiO 2 ÁH 2 O) and for 4 h from natural rocks (decalcinated chalk marl, opoka). DSC and XRD analysis showed that remaining portlandite and part of a-C 2 SH decompose during 5 min of intensive tribochemical activation of the synthesis products and quartz mixture. Unfortunately, according to TG data, water released from these compounds remains in the sample. Applying different types of mills as well as the adding water adsorbents (CaO, CaCl 2 and BaO) has no effect on the hydraulic activity of the binder: The results of microcalorimetric analysis indicate that heat flow values of the main hydration reactions decreased in all cases. Most suitable way of removing water from the samples is lowtemperature thermal treatment at 450°C. Milled a-C 2 SHquartz mixture exhibited good binding properties after burning mixtures at this temperature. The mortar with the highest compressive and bending strength values (20.43 and 5.17 MPa after 28 days of hydration) was obtained using mixture which consisted of 25 % (by mass) synthesis product (obtained from hydrothermal synthesis of opoka and chalk marl), 25 % together with a-C 2 SH-milled quartz sand (during the tribochemical activation) and 50 % standard sand.

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“…The material life cycle of concrete was analyzed by Woodward and Duffy (2011). With respect to environmental implications, Uwasu et al (2014) argued that it is of critical importance to control excessive cement demand. Gao et al (2014) found that replacing carbonatecontaining materials with non-carbonate materials and changing the clinker ratio are primary solutions for reducing natural resource consumption and process emissions.…”

Section: Introductionmentioning

confidence: 99%

Analysis of material flow and consumption in cement production process

Tianming

Shen

et al. 2016

Journal of Cleaner Production

115

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a b s t r a c tCement production, which is highly dependent on the availability of natural resources, will face severe resource constraints in the future. This is especially true for the cement industry in China. Thus, the industry is focusing on reducing the consumption of natural resources at both the manufacturing and operational stages. The aim of this article is to improve the management of resources used in the cement production process and mitigate their environmental effects. First, material flow routes for the cement manufacturing process are established, after which three mass balances are built during the three production stages using actual plant data received from an existing cement manufacturing facility. Finally, the material efficiency of the units and stages as well as the waste recycle rates during these stages is calculated. The results show that approximately 2.48 t, 4.69 t, and 3.41 t of materials are required to produce a ton of the product in raw material preparation, clinker production, and cement grinding stages, and their waste rates are 63.31%, 74.12%, and 78.89%, respectively. The recycling rate of wastes during clinker production is remarkably higher than those during other manufacturing stages, wherein waste gases are directly discharged into the atmosphere. The material efficiency values for a raw mill, pyro-processing tower, rotary kiln, clink cooler, and cement mill are determined to be 36.69%, 34.24%, 39.24%, 29.76%, and 25.88%, respectively, whereas the waste recycling rates for these units are found to be 16.33%, 81.98%, 100.00%, 99.53%, and 0.00% respectively. These results will provide researchers with knowledge regarding the effectiveness and efficient use of natural resources in the cement sector. These important findings can also be used to influence the development of national and industrial policies in relation to the goal of achieving sustainable development in the cement industry.Crown

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World cement production and environmental implications

Cited by 90 publications

References 22 publications

Sustainable Materials for Transportation Infrastructures: Comparison of Three Commercially-Available Metakaolin Products in Binary Cementitious Systems

Sustainable Materials for Transportation Infrastructures: Comparison of Three Commercially-Available Metakaolin Products in Binary Cementitious Systems

Heat flow and strength properties of perspective hydraulic binder material

Analysis of material flow and consumption in cement production process

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