Use Of Clinker Research Articles

Geological evaluation of black shale as a suitable Supplementary Cementitious Material (SCM) to optimize the use of clinker in cement production

Faced with challenges like resource depletion and climate change, the cement industry needs sustainable solutions. This study explores the potential of geologically-delinaeated black shale from Apersua, Ghana, as a supplementary cementitious material (SCM) to reduce reliance on traditional methods. The researchers analysed the shale's chemical composition and mineralogy, then created laboratory cement formulations with varying black shale content. These were compared to standard formulations without shale. The results show cement with black shale has comparable compressive strength, meeting standard requirements. Even a formulation with only black shale (excluding limestone, a common ingredient) passed strength tests. Overall, the black shale demonstrated good potential as a SCM based on strength, chemical makeup, setting time, and its possible contribution to durability. This research suggests that black shales from Apersua are worth exploring further as a sustainable and potentially cost-effective alternative in cement production.

IMPROVE THE COMPRESSIVE STRENGTH USING A STRENGTH IMPROVER AGENT (SIA) IN THE CEMENT INDUSTRY IN INDONESIA

Greenhouse gas emissions such as CO2 are released during clinker production through various processes, including the calcination reaction of limestone (CaCO3). To reduce CO2 emissions per ton of cement produced, some studies have explored the use of clinker substitutes. However, a reduction in the amount of clinker can also result in decreased compressive strength of the cement. To address this issue, the addition of a Strength Improver Agent (SIA) can be used to maintain the necessary compressive strength and ensure compliance with all relevant standards. Therefore, This study aimed to determine the optimal amount of SIA required to achieve the desired compressive strength. The study added SIA in varying amounts (100, 150, 200, 250, 300, 350, and 400 ppm), and the compressive strength of cement was measured at 1, 3, 7, and 28 days based on ASTM C 109 and QPT-LAB-SNI-05 standards. Physical tests were also conducted, including Blaine, 325 mesh residue, Insoluble Residue (IR), Loss on Ignition (LOI), and XRF based on ASTM C 114, ASTM-STP 985, XRF Thermo ARL 8480S. The observations and analysis showed that the optimum amount of SIA addition is 350 ppm, where the resulting compressive strength increases at least 7% compared to blanks.

The Effect of Active Additives and Coarse Aggregate Granulometric Composition on the Properties and Durability of Pervious Concrete.

Pervious concrete (PCO) has many advantages and applications, such as water pooling reduction, noise attenuation, replenishment of groundwater reserves, etc. However, the use of pervious concrete is limited due to its low compressive strength and durability, especially as a result of portlandite leaching from concrete exposed to flowing water. The effects of active additives (nano SiO2 (NS) spent catalyst generated at the fluid catalytic cracking unit (FCCCw) and paper sludge waste burned at 700 °C (PSw)) along with particle size distribution of the coarse aggregate on the properties and durability of pervious concrete were determined in the research. Active additives used in the binder were found to reduce portlandite leaching from concrete exposed to flowing water to significantly increase the resistance of concrete to freezing and thawing cycles and to increase sound absorption, compressive strength and infiltration rate. In addition, industrial waste (FCCCw and PSw) used as active additives significantly reduced the use of clinker in concrete applied in the construction of water pervious systems. The coarse aggregate size distribution had the greatest effect on the density, ultrasound pulse velocity (UPV), porosity, compressive strength and infiltration rate of pervious concrete.

Combined effect of powdered dune sand and steam-curing using solar energy on concrete characteristics

This paper explored an economic, environmental and technological alternative, namely steam-curing using solar energy, which harnesses solar radiation to accelerate cement hydration and increase the pozzolanic activity of powdered dune sand (PDS) by activating the less reactive silica; thus allowing the concrete to acquire high initial strengths. In addition, using PDS, as cement addition, reduces the use of clinker. Combined effect of PDS and steam-curing on concrete characteristics is worth studying. The effect of different PDS rates on both workability and mechanical strengths at various ages of water-curing was investigated. Thereafter, the effects of curing procedures on mechanical strengths of specimens incorporating PDS were examined. Three curing methods were used: water-curing and steam-curing at 42 °C, at 26 °C. Indeed, it was essential to determine the optimum PDS rate and appropriate steam-curing cycle. Finally, the effect of subsequent water-curing after steam-curing at 42 °C (SC42) was also studied. The results reveal that PDS plays a beneficial role on the workability up to the rate of about 15%. It should be noted that there exists an optimal rate of around 10% PDS for which higher mechanical strengths are obtained at 28-day and 60-day. SC42 is more useful than at 26 °C because the pozzolanic activity of PDS begins to be significant from the third day. After 3 days of SC42, the highest compressive strength (Cs) at 28 days was achieved at 10% PDS. Flexural strengths were in great accordance with the Cs regardless of the PDS rate and the steam-curing cycle. SC42 and up to 20% PDS, not only improves mechanical strengths, but also reduces production costs in addition to significant environmental impact. It is essential to use the technique of subsequent water-curing (of 3-day) because it has a significant effect on the compressive strengths of concretes containing PDS after 3-day of SC42. Results confirmed that PDS can be used as an addition to cement in the production of precast concrete using eco-friendly and economical technique. This finding has significant implications for the economics of concrete construction in the southern regions of the country where the dune sand is very abundant.

Synergistic effects of rubber-tire-powder and fluorogypsum in cement-based composite

Currently, the use of waste materials in Portland cement mixtures and the reduction of the use of clinker is important due to environmental issues. One of the waste materials of importance for the scientific community is end-of-life tires, because there are millions of tires in landfills; however, there are other materials in similar circumstances such as fluorogypsum. In this study, the effect of incorporating two waste materials (rubber-tire-powder and fluorogypsum) was studied in a Portland cement mixture diluted with CaCO3. The remnant of H2SO4 contained on the surface of fluorogypsum is an option to chemically treat the surface of the tire particles and improve their interaction with the cement matrix. The characterization of the chemically treated material, the hydration evolution and the physico-mechanical properties were evaluated. In the hydration process, it was observed that a low fluorogypsum content slightly accelerated the cement reactions, while the rubber-tire-powder inhibited them. Regarding the cement-rubber mixture, the cement-rubber-fluorogypsum mixture had a recovery of 28.3 % in the compressive strength and 36.0 % in the modulus of elasticity. The results of this research show that using the two waste materials simultaneously is advantageous because it improves the properties of the cement-tire and avoids the use of other surface treatments. This makes it possible to obtain a more ecological and relatively cheaper cementitious material than with the application of other surface treatments on the rubber-tire particles.

Toward the best practice emissions reduction in an emerging economy: an analysis of cement manufacturing in Indonesia

Cement manufacturing is an energy-and carbon-intensive process and a prominent contributor to global anthropogenic greenhouse gases (GHGs). Within emerging economies, this industry’s considerable potential to pollute can be exacerbated by outmoded plant or practices, and management’s limited capacity to remediate. In this context, the current study analyses the case of Indonesia’s leading producer, recording variations in greenhouse gas (GHG) sources to pinpoint opportunities for reduction. Emissions, measured 20% higher than the 2030 global industry target, occur from the calcination process, abetted by fuel combustion. Reductions should be focused on reducing the clinker-to-cement ratio and promoting the uptake of alternative fuels. Avenues lie in increasing the use of clinker substitutes such as fly ash and limestone, and employing fuels derived from waste and biomass. Both sources are abundant in Indonesia. Further declines in GHGs could be achieved through technological innovations such as the upgrading of kilns. The inquiry provides recommendations for emission mitigation in the cement industry not only in Indonesia but also in other developing countries.

Adobe bricks reinforced with paper & pulp wastes improving thermal and mechanical properties

Soil-based building material has been used since ancient times but lately it has been mainly considered for restoration purposes of traditional architecture instead of an eco-friendly construction material for new buildings. However, the promotion of a more sustainable architecture has recently led to look towards adobe or rammed earth, among others. Because of the high impact of concrete and the fired clay brick industry, mainly due to the use of clinker and the firing process, respectively, adobe may highly reduce the ecological footprint of conventional construction and building materials. In addition, the use of fibers for adobe reinforcement has been also highlighted as a key factor for improving adobe performance. Obviously, when residues successfully replace such fibers the ecological footprint may be reduced even more. Thus, this research focuses on the assessment of adobe reinforced with paper and pulp industry residues (PPR) with the aim of demonstrating the feasibility of this construction material. Several series have been made by varying the replacement percentage up to 20% and technological properties and toxicity have been assessed. It is concluded that compressive strength may be improved up to 190% while thermal conductivity is reduced approx. 30% for 12.5% of PPR replacement. Besides, adobe meets standards related to water resistance and toxicity values.

Effect of protogenetic anhydrite on the hydration of cement under different curing temperature

Compared with the added gypsum, protogenetic anhydrite is the anhydrite in clinker and cement admixture. And using protogenetic anhydrite as the setting retarder instead of added gypsum to make cement could be an effective way to make full use of clinker and wastes with high sulphur content. However, the high temperature sensitivity of solubility property of protogenetic anhydrite may result in unhydrated anhydrite exist in cement paste under high curing temperature at early age, and that may make a bad influence on the properties of cement. This work investigated the effects of protogenetic anhydrite on the long-term strength, volume stability and hydration products of cement paste under different curing temperature. It is shown that higher curing temperature caused the greater value of optimum content of protogenetic anhydrite in cement, and protogenetic anhydrite could not make the bigger volume expansion and worse strength of cement than gypsum when the high curing temperature being used. But curing temperature caused the dissolution of protogenetic anhydrite change and influenced the concentration of sulfate ion in the pore solution of hardened cement paste. The results of XRD patterns showed that the risk of delayed ettringite formation in hardened cement paste cured at high temperature had been increased. The results will be helpful to understand the role of protogenetic anhydrite in cement, and further promote the use of clinker and wastes with high sulfate.

Cement industry greenhouse gas emissions – management options and abatement cost

Growing anthropogenic greenhouse gas emissions and increasing global demand for cement are general drivers for managing greenhouse gas emissions (GHG) in the cement industry. Overall CO2 dominates cement sector GHG emissions. The aim was to study how the management of GHG emissions in the cement production chain is related to (1) clinker substitutes, (2) primary source of energy, (3) electricity emissions, (4) technology in use and (5) geographic location. Therefore regional CO2 emissions in the cement industry were analyzed by applying a climate impact management matrix on a cradle-to-gate basis. The use of clinker substitutes in cement varied from 3% to 36.4%. The results show that the variation of process technology and thermal energy use related CO2 emissions is more significant than that of electricity emissions. The highest near term potential to avoid emissions is replacing clinker with mineral components (MIC). Increasing the global use of MIC to a level of 34.2%in cement would save 312 Mt CO2 with the 2013 level of annual cement production. Similarly, a 2.7% reduction in thermal energy use would save 28 Mt CO2 annually, and a 10% decrease of emissions from electricity use would save 26 Mt CO2. The best long term options from 2030 onwards are different carbon capture technologies and MgO and geopolymer cements. In addition, the CO2 abatement costs of different investment projects were compared by using a uniform capital recovery factor. The abatement cost of avoided emissions varied from US$4 to US$ 448 per ton of CO2 depending on the technology, geographical location and initial level of CO2 emissions.

비소성 시멘트 콘크리트의 역학적 거동에 대한 실험 연구

클링커 대신 고로슬래그, 폐인산석고, 폐석회 등의 산업 부산물을 이용하여 비소성시멘트를 제조하면 산업부산물 재활용, 클링커 제조를 위한 에너지 감소, <TEX>$CO_2$</TEX>저감으로 인한 환경오염문제 및 생산원가 저감 등의 장점이 있다. 이러한 이유로 본 연구에서는 비소성 시멘트 콘크리트의 역학적 거동실험을 수행하여 비소성 시멘트 콘크리트의 탄성계수, 응력-변형률 관계를 제안하였다. 또한 철근비, 압축강도를 변수로 9개의 구조 시험체를 제작하였으며, 그 실험 결과 비소성 시멘트 콘크리트의 휨 및 전단 거동 경향은 일반 콘크리트 부재와 크게 차이나지 않는 것으로 나타났다. If cement could be manufactured with industrial byproducts such as granulated blast furnace slag, phosphogypsum, and waste lime rather than clinker, there would be many advantages, including the maximization of the use of these industrial byproducts for high value-added resources, the conservation of natural resources and energy by omitting the use of clinker, the minimization of environmental pollution problems caused by <TEX>$CO_2$</TEX> discharge, and the reduction of the production cost. For this reason, in this study, mechanical behavior tests of non-sintered cement concrete were performed, and elasticity modulus and stress-strain relationship of non-sintered cement concrete were proposed. Nine test members were manufactured and tested according to reinforcement ratio and concrete compressive strength. According to the test results, there was no difference between general cement concrete and non-sintered cement concrete in terms of flexure and shear behavior.

Effect of adsorbents on the leachability of cement bonded electroplating wastes

This study is aimed at the determination of pore solution composition of hardened cement pastes prepared with the addition of chromium-, cadmium- and nickel-salts. Due to the high pH-value of the pore water of cement paste, cadmium and nickel were transformed into insoluble hydroxides and precipitated practically quantitatively. Chromium, added as Na 2Cr 2O 7.2 H 2O, which is soluble in a highly alkaline medium, was partly bound. It is not clear yet, whether chromium was adsorbed and/or incorporated in hydration products. The use of clinker instead of cement caused a more intensive bond. Adsorbents (silica fume, fly ash and activated carbon), with the exception of fly ash did not improve this bonding.