Clinker Substitution Research Articles

Four-years influence of waste brick powder addition in the pore structure and several durability-related parameters of cement-based mortars

The service life of real construction elements is usually long, so the study of the behavior of cement-based materials with new pozzolanic additions in the very long term, after several hardening years, could be interesting. Here, the influence of using waste brick powder as 10% and 20% clinker substitution in microstructure and several durability-related parameters of mortars after 1500 hardening days (approximately 4 years) has been studied. According to the results obtained, the incorporation of brick powder overall improved the performance of mortars after 4 years, compared to reference mortars without addition, especially regarding the pore structure and chloride diffusion.

Evaluation of CO2 Emissions Reduction Strategies in the Iranian Cement Industry

Portland cement as the main constituent of conventional concrete is the most widely used cementitious material in the construction industry. But Portland cement production has major environmental disadvantages, including high energy consumption and carbon dioxide (CO2) emissions. So that production of Portland cement is accounted for 7 to 10% of global CO2 emissions. Considering the amount of Portland cement production and CO2 emissions in Iran, it can be concluded that Iran is facing environmental problems caused by cement production. Hence, various CO2 emissions mitigation strategies of Iranian cement industry have been evaluated in this study. This research work applied Analytical Hierarchy Process (AHP) method to evaluate and prioritize mitigation strategies. The obtained results showed that among the 16 strategies studied, clinker substitution (blended cement) and production of low carbon cements such as geopolymer cement were recognized as the most important strategies to reduce CO2 emissions in the Iranian cement industry.

Screening for key material parameters affecting early-age and mechanical properties of blended cementitious binders with mine tailings

Considering the vast amounts and wide variability of tailings available worldwide, means to assess the potential of tailings for cement clinker replacement based on their physical, chemical and mineralogical characteristics would be useful. This work studied the early-age properties and mechanical performance of mortar of Portland limestone cement (CEM II/A-LL) clinker in a ternary blend with partial clinker substitution by 13 metal and mineral mine tailings. The properties studied included workability, setting time, porosity and compressive strength. The effects of replacement level and mine tailing characteristics on the performance of mortar were assessed by chemometrics.The results showed that most mine tailings reduced the workability of mortar (3–19 %) and that an increased replacement level reduced the workability further. For most mine tailings, the initial setting time was identical to the reference, while they reached the final setting faster. Tailings had a variable impact on the porosity at low replacement, while porosity generally increased at a higher replacement. The compressive strength decreased with increasing replacement in most cases, and a clear negative correlation was found between compressive strength and porosity. However, five mine tailings developed up to 10 % higher strength after 28 days with 20 % supplementary composite material compared to the reference.Chemometric analyses showed that tailings with high specific surface area and silicon dioxide content influenced the mechanical properties of the mortar most positively. Conversely, larger grain sizes, high loss on ignition, calcium oxide and calcium carbonate content impacted compressive strength negatively.The analyzed characteristics do, however, not fully explain the resulting early-age and mechanical properties, thus additional investigations are needed to understand the performance in detail.

EFFECT OF LIMESTONE POWDER ON THE PROPERTIES OF BLENDED РORTLAND CEMENTS

The article shows the relation between sustainability and cement manufacture that can be obtained by the replacement of clinker with limestone additive. This decreases the use of energy resources and reduces CO2 emissions in cement production. The issue of partial Portland cement clinker substitution by finely ground limestone in the production of market-oriented types of cement type CEM II is solved on the cement plant PJSC "Ivano-Frankivsk Cement". The indexes of physical-mechanical tests of certified Portland limestone cement with high early strength CEM II/A-LL 42.5 R produced by PJSC "Ivano-Frankivsk Cement" are given. Finely dispersed limestone in Portland-composite cements with slag promotes a more complete synergic effect. It is established, that rapid-hardening blended Portland cements with limestone powder provide technological, technical, ecological, and economic effects in the production of prefabricated and monolithic reinforced concrete.

Decarbonizing cement production

Paul Fennell is a professor of clean energy at the Department of Chemical Engineering, Imperial College London. His work encompasses the decarbonization and re-thinking of industrial processes, including the production of iron and steel and cement manufacture. He also works in the broader field of industrial decarbonization, including synergies between industry and power generation. Steve Davis is a professor of Earth system science and civil and environmental engineering at the University of California, Irvine, where he researches trends and drivers of GHG emissions, net-zero emissions energy systems, and the environmental impacts of energy production, climate change, and international trade. Aseel Mohamed received an MSc in advanced chemical engineering from Imperial College London. Her research focused on investigating the various decarbonization technologies used to capture CO2 emissions in order to mitigate climate change effects.

Mechanisms dominating thixotropy in limestone calcined clay cement (LC3)

Limestone calcined clay cement (LC3) is a green binder with great practical importance for the cement industry. Growing application has increased the need to understand the mechanisms governing its thixotropy for better control of workability. While formation of C-S-H bridges is understood to dominate the thixotropy of ordinary Portland cement, LC3 paste displayed unique thixotropy properties. In this study, focused beam reflectance measurement, zeta potential, 1H nuclear magnetic resonance relaxometry and micro X-ray computed tomography were used to track the colloidal interaction and hydration extent within LC3 paste. Results showed that flocculation due to the negative surface charge and water affinity of calcined clay appears to be the dominating factor. This leads to a reduction of water available to contribute to fluidity of the paste and, in turn, governing the development of thixotropy over time. In addition, the dilution effect due to high clinker substitution diminishes thixotropy growth with time.

Quality Assessment of Clay for Limestone Calcined Clay Cement Production

Being the biggest material utilized by humanity after water, concrete and related businesses have grind sway on development and improvement of a nation. Despite the fact that generally modest, the way toward making its fixings produces CO2. The significant offer for this natural issue from concrete is because of the creation of concrete which is a basic segment. Discharges from concrete creation are predominantly because of development of clinkers which are fundamentally concrete knobs which blend and crush with gypsum to deliver Ordinary Portland concrete C (OPC). It requires the crude materials to be warmed at high temperature (up to 1500°) to create clinker. The synthetic procedure associated with clinkerization where the limestone changes into lime and CO2 is answerable for 50-75 % of outflow. Utilization of electrical vitality required to pound the crude materials likewise contributes its offer. Because of the raising worry against the ozone harming substance discharges and a dangerous atmospheric deviation, ventures and nations are encouraged to see vital strides to check this worldwide issue. It is evaluated that concrete industry is liable for around 6-8% of worldwide CO2 outflow. As it is the quickest developing economy and amongst the most populated nations on the planet, India is about to turn into the biggest shopper of concrete in not so distant future by surpassing China. Because of exponential consumption of value crude materials just as ecological issues from the customary OPC creation, it is critical to take a gander at substitute approaches to deliver the folio in India. The most well-known and broadly acknowledged technique is clinker substitution by strengthening cementitious materials (SCMs). As significant piece of the electrical vitality in the nation originates from coal based warm force plant, which produces fly debris, a SCM all in all; a great deal of examination has been done in the use of fly debris in concrete creation. As of now according to the Bureau of Indian Standard (BIS), 30-40% of clinker can be supplanted with fly debris which meets the necessary quality standards. Despite the fact that, because of the absence of accessibility great quality fly debris and different government guidelines, the complete piece of the overall industry of fly debris based PPC in India, is around 65% as it were.

Influence of cement strength class on environmental impact of concrete

Traditional approaches to reducing the CO2 emissions of cement production are effective yet insufficient, which has driven new research and innovations. A potential alternative that has been poorly explored is optimizing the physical and chemical characteristics of cement to enhance the dosage efficiency for concrete, which can reduce both cement consumption and CO2 emissions. This approach demands an understanding of the potential savings according to the cement strength. In practical terms, increasing the cement strength requires more electric energy to grind cement into finer particles, which ensures that most of the clinker and other reactive particles are hydrated at 28 days; and increasing the reactive phases of the cement, such as the clinker content. Both options improve cement reactivity and can reduce cement consumption to achieve the same mechanical performance of concrete. The objective of this study was to investigate the potential reduction in the CO2 footprint of concrete mixes with cements of different strength classes and discrete clinker substitution ratios. The effect of grinding finer cement on reactivity was also evaluated. The carbon abatement costs were estimated according to the additional CO2 emissions from cement grinding and potential CO2 reduction from a smaller dosage.

Color control in industrial clay calcination

The combined use of calcined clays and limestone in the ternary system LC3 enables up to 50% of clinker substitution without affecting the performance. Low grade calcined clays are rich in iron. If calcined in an oxygen rich atmosphere, they turn to red. Cement producers avoid selling cement with a color different to the traditional. This paper proposes a method to modify color during calcination by controlling the atmosphere during the cooling. At calcination, the high temperature favors the formation of magnetite even at oxidizing conditions. However, during the cooling phase, magnetite can convert back to hematite if oxygen is available and the calcined material will have a reddish color. The procedure to control color consists of injecting liquid fuel at the carcass of the kiln while the calcined material exits, so that it combusts and exhausts the oxygen available during the cooling process. The procedure was successfully implemented at a pilot kiln in India. Controlling the calcination atmosphere enabled the production of a black calcined clay, instead of a red material. The reactivity and properties of both red and black clay are very similar, and no side effects have impacted properties of LC3 cements produced with the treated clay.

Dispersing performance of different kinds of polycarboxylate (PCE) superplasticizers in cement blended with a calcined clay

This study investigates the dispersing effectiveness of purposely selected methacrylate ester (MPEG), isoprenol ether (IPEG) and methallyl ether (HPEG) based polycarboxylate (PCE) superplasticizers of different molecular structures in cements blended with 0–50 wt% of a calcined clay (CC) rich in meta illite–smectite. It was found that the water demand of the composite cements increases lineraly with the rate of clinker substitution, and that PCE dosages also increase proportionally with the amount of CC, namely approximately doubled at 50% clinker substitution. Among the PCEs, HPEG polymers proved most effective while MPEG and especially IPEG PCEs required higher dosages.

A Framework for Green Concrete Noise Barrier Materials using Palm Oil Clinker

Noise pollution from traffic is an increasing environmental problem worldwide. The most popular mitigation measure is the control of path by means of construction of noise barriers. Current concrete barrier incorporated with perforated surface infilled with non-mineral fibre sound absorbing material on the highway side are the commonly found. The disadvantage of this type is it’s easily damaged and the non-mineral fibre is so dreadful to human health. On the other hand, palm oil clinker (POC) is a by-product waste material produced in palm oil mills, are currently dump in open land or landfill sites, which leads to environmental problems. POC is internally porous and if it replaces the aggregate in porous concrete it may absorb sound better than standard porous concrete which is the most important characteristic for noise barrier development. This paper discusses how the palm oil clinker substitution will make concrete noise barrier material to be labelled as green and sustainable. A framework for developing green noise barrier made of palm oil clinker concrete will also be presented and discussed.

Low clinker high performance concretes and their potential in CFRP-prestressed structural elements

Three novel low-clinker-high-performance concretes (LCHPC) with clinker replacement levels of 54, 58 and 70% were developed to substitute high-performance concrete (HPC) in carbon-fiber-reinforced-polymer (CFRP) prestressed structural elements. The clinker substitution was achieved by a high amount of limestone filler and smaller amounts of metakaolin and silica fume. After 28 days, the LCHPCs reached high compressive strength values, between 77 MPa and 88 MPa, and Young's moduli between 35 GPa and 44 GPa. The LCHPCs showed self-compacting properties and low creep and shrinkage in comparison to a reference HPC.A finite element analysis (FEA) of the internal stress development over time in CFRP-prestressed structural elements was performed, including creep and shrinkage. A higher prestress level was maintained in the LCHPCs compared to the reference concrete, thanks to their low shrinkage and creep. In contrast, the use of ultra-high-modulus CFRP prestressing tendons leads to increased pre-stress losses.

The scope for better industry representation in long-term energy models: Modeling the cement industry

Although the cement industry emits around 6% of global CO2 emissions, most global Integrated Assessment Models (IAMs) barely represent this industrial subsector or do not cover all important processes. This study, describes the state-of-the-art of cement modelling in IAMs, suggests possible improvements and discusses the impacts of these on energy and greenhouse gas emissions (GHG) in the IMAGE global IAM.It is found that two cement-sector specific GHG mitigation measures are often not explicitly accounted for in IAMs, namely: (i) retrofitting and (ii) reducing the clinker to cement ratio. For retrofitting, many measures are identified as cost-effective and when incorporating these in the IMAGE model overall energy use reduces between 2010 and 2035 by 9.8 and 11 EJ (4% and 5%) under the baseline and GHG mitigation scenarios, respectively. When incorporating the clinker to cement ratio by linking material availability to the activities in the steel industry and coal-fired power plants, the 2050 energy use reduces by 15% under the baseline scenario and increases by 9% under the GHG mitigation scenario as fewer coal-fired power plants are in operation. This is even more prominent in the long term. The 2100 energy use is 14% higher in the GHG mitigation scenario as even fewer coal-fired power plants are used drastically limiting the potential for clinker substitution with fly ash. These results highlight the importance of capturing cross-sectoral relationships between industries and of including sector specific mitigation measures in long-term energy models.

Carbon Management in an Emissions-Intensive Industry in a Developing Economy: Cement Manufacturing in Indonesia

Around 600 Mt carbon dioxide equivalents (CO2e) of anthropogenic greenhouse gases (GHG) emission originates from energy production and consumption in Indonesia annually. Of this output, 40 Mt CO2e comes from cement production. This makes the cement industry a key sector to target in Indonesia’s quest to reduce its emissions by 26% by 2020. Substantial opportunities exist for the industry to reduce emissions, mainly through clinker substitution, alternative fuels, and the modernization of kiln technologies. However, most of these abatement options are capital intensive and considered as noncore business. Due to this, the private sector is unlikely to voluntarily invest in emission reduction unless it saves money, improves revenue, enhances the strategic position of the firm, or unless governments provide incentives or force adoption through regulatory and policy controls. In this study, we review the profile of the Indonesian cement industry and assess the carbon management and climate policy actions available to reduce emissions. The case highlights opportunities for improved carbon management in emission-intensive industries in developing countries.

Policy making in the cement industry for CO2 mitigation on the pathway of sustainable development- A system dynamics approach

Due to the ongoing rise of the earth surface temperature related to human activities and the socio-economic impacts of environmental stress, our long-term welfare is intertwined with sustainable development. Production of cement, as the primary material of construction, is associated with high environmental pollution and tremendous energy consumption. Considering the limitations of fossil fuel resources and strict environmental regulations, achieving sustainable production of cement is a critical initiative to be followed. In Iran, more than 26% of the total energy is consumed by industries and the share of the cement industry is 13%. In addition to high energy consumption concerns, the use of inefficient technologies for cement manufacturing has led to a huge release of CO2. Accordingly, in this study, a system dynamics approach is developed based on the Iranian cement industry to investigate the effects of three energy efficiency measures (clinker substitution, alternative fuel use, and waste heat recovery) on realizing sustainability over the period of 2015–2034. As a result of simulation, utilizing clinker substitution could potentially lead to reduction of 13% and 11%, respectively in CO2 emissions and energy consumption costs. It also creates more opportunities for exporting fossil fuels which leads to improve the country’s balance of trade. On the other hand, installation of waste recovery is proven to have less influence on CO2 mitigation, while leading to an enhancement of 4.5% in manufacturer profit.

Steady viscous flow of some commercial Andean volcanic Portland cement pastes

Three commercial Ecuadorian cements, obtained from crushing a mix of clinker and a mixture of pumice powder and volcanic ash, were selected to perform studies on steady viscous flow behaviour. Steady flow curves were obtained during the dormant period. All pastes showed non-linear viscoplastic behaviour. A modified Bingham model was fitted to the experimental data. The yield stress was found to increase and plastic viscosity decreased with clinker substitution. These results were justified by using a model that considers fresh volcanic cement paste as a suspension of particles (cement and volcanic powder) dispersed in a liquid phase, formed by water, and a gel part, formed from the cement–water chemical reaction.

Assessment of pore structure evolution in the limestone calcined clay cementitious system and its implications for performance

Use of limestone and calcined clay together for clinker substitution makes an effective low clinker cement blend, which shows promising mechanical properties at early ages. The performance of these cementitious systems strongly depends on the pore structure, which is a dominant factor governing the durability characteristics because of its direct influence on the transport properties. The experimental study described in this paper on three different binder systems including Ordinary Portland Cement, Portland Pozzolana Cement - with 30% Type F Fly Ash (designated FA30) - and Limestone Calcined Clay Cement (LC3) pastes shows that the LC3 system attains greater refinement of the pore structure as early as 3 days, as seen from mercury intrusion porosimetry. Electrical measurements also reveal lower conductivity in the system, which suggests better resistance to ionic transport in the binder phase. The results of hydrate phase assemblage studied by X-ray diffraction also indicate that greater amount of hydrates contribute in a major way to the reduction in the (water-filled) porosity in all the systems. This change occurs at varying rates for the different systems due to the difference in hydration characteristics. The estimated permeability suggests that the LC3 binder system attains much lower permeability compared to the ordinary Portland cement and FA30. A comparison of the formation factor shows distinct differences in the microstructural development and suggests a more durable binder with LC3 cementitious system.

Microstructure-Based Evolution of Compressive Strength of Blended Mortars: A Continuum Micromechanics Approach

The evolution of stiffness and strength belong to the most important properties of mortars. Motivated by an increasing demand for clinker substitution by supplementary cementitious materials (SCMs), this paper presents a multiscale model for prediction of elastic stiffness and compressive strength of blended mortars. Mortars are envisioned as hierarchically organized materials with microstructural phases spanning several orders of magnitude. On the scale of hundreds of nanometers, "CSH foam" consists of amorphous calcium silicate hydrates mixed with capillary pores which on the scale of hundreds of microns acts as a contiguous matrix reinforced by unhydrated clinker, SCM grains, and by crystalline hydration products forming "cement paste". The largest scale of observation describes mortar as quartz sand aggregate inclusions embedded into a contiguous cement paste matrix. Continuum micromechanics homogenization approach is used to upscale stiffness from calcium silicate hydrates, represented by needle-shaped ellipsoids, up to the scale of mortar. Macroscopic quasi-brittle failure of mortar is associated with a concentration of strain energy density-related microscopic stresses within a critically oriented needle-shaped hydrate in "CSH foam". Successful model validation on OPC-based and blended mortars provides strong evidence that continuum micromechanics is an efficient tool for quantification of stiffness and compressive strength.

Potential of Fly Ash Utilization for the Clinker Substitution in Cement Industry in Thailand

The main objective of this article is to forecast CO2 mitigation from clinker production and to evaluate Fly Ash potential, used Clinker Substitution for CO2 mitigation in cement industry between years 2015-2036 in Thailand following information of the Thailand's power developments plan (PDP2015). PDP2015 forecasts the potential of fly ash in the year 2036 which is estimated at 3.94 M ton and 48.76 M TonCO2 of CO2 emission from 58.01 M Ton of clinker production process. The methodology which is used for potential evaluation of fly ash and amount of CO2 can evaluate from Mae Moh power plant technology. 1 MW can occur 952.3427 Ton and amount of CO2 emission from utilizing is 0.825 TonCO2/TonneCli which is a default value of CSI (Cement Sustainability Initiative).The three different scenarios are used to analysis in this study. The condition of Business As Usual (BAU) scenario is the need of technology, used in 2015 as a base case. The full potential scenario (FP) is represent to the 100% fly ash using. The final scenario is called Zoning scenario (Z scenario) which consists of price rate (270 THB per Ton) and transportation rate (6 THB per kilometer of fly ash). From the result, in 2036 fly ash occur 7.46 M Ton that can mitigate CO2 volume up to 6.15 M TonCO2

The use of ternary cements to reduce the environmental impact of concrete

In the current context of climate change, reducing the greenhouse gas emissions is one of the greatest challenges of our society. As concrete is the second most used material in the world after water, its environmental impact is significant, especially because of the production of cement. Clinker substitution is according to the International Energy Agency and the World Business Council for Sustainable Development one of the four main reductions levers for the cement industry. Unlike Carbon Capture and Storage technology, replacing clinker with by-products such as fly ash and blast-furnace slag is technically feasible and applicable today. The use of blended cements is nowadays more and more commonly widespread. Ternary cements is particularly advantageous to benefit the synergetic action of two substitutes such as fly ash and limestone filler. Cement standard EN 197-1 is evolving towards more ternary binders but their impact on concrete properties are not thoroughly investigated yet. This paper presents some effects of newly developed ternary cements on concrete. The use of composite cements is a compelling solution to reduce the environmental impact of concrete but it is necessary to always assess their suitability in concrete.