Cement Type CEM Research Articles

Green Innovation for Carbon Footprint Reduction in Construction Industry

The cement-based mixture market or dry mix for the ETICS (External Thermal Insulation Composite System) is a highly competitive market and it is becoming increasingly difficult to comply with European sustainability specifications such as the development of products with a lower carbon footprint, lighter and less energy-intensive materials, lower environmental impacts, the option of recycling, etc. This market plays a highly important role in the construction sector, not only for the technical solutions and green innovation it offers but also for the aesthetic aspects. Since 2005, this market has been growing by more than 20% per year, which makes it increasingly attractive with better opportunities. However, this increase has been reduced not only by the crisis of 2007–2008 but also by the pandemic of recent years. The use of cement type CEM II, 42.5R, B-LL, together with a modified RDP ratio, has visibly improved the properties of the thermal insulation system through the adhesion of the EPS boards, the modulus of elasticity, wear resistance, flexibility, and impact resistance. Our research results as green innovation products are above the minimum values agreed by the ETICS standards; in addition, this product has in its formulation a 30% lower carbon footprint compared to any other adhesive in the construction market applied for ETICS systems; therefore, we are talking about a sustainable and clean product, suitable for rehabilitations and ecological constructions adjusted to the European policies of carbon footprint reduction.

Effects of Recycled Expanded Polystyrene Beads on the Mechanical and Physical Properties of Cement-Stabilized Compressed Earth Bricks

Nowadays, research on environmentally friendly materials has become a significant challenge in the field of civil engineering. In this study, stabilized compressed earth bricks (CEBs) incorporating recycled expanded polystyrene (EPS) beads were studied with the aim of enhancing the development of green constructions. The mass contents of recycled EPS in CEB formulated at a compaction pressure of 5 MPa are 0%, 0.25%, 0.5%, 0.75%, and 1% relative to the mass of the soil, while cement type CEM I 32.5, as a stabilizer, constituted 8% by mass. Characterization was carried out by determining densities, dry and wet compressive strength, flexural strength, total water absorption, and capillarity. Sample properties were found to be strongly influenced by the percentage of recycled EPS. Increasing the EPS aggregate content led to a reduction in compressive strength in both wet and dry conditions. Samples with 0.5% EPS and 8% cement offered better physical and mechanical performance. Samples containing EPS had relatively low water absorption, which would contribute to good durability. These CEBs comply with the wall construction requirements for two-story dwellings. This study also demonstrates the potential use of this recycled material in the construction industry.

Effect of Portland Cement on Mechanical and Durability Properties of Geopolymer Concrete at Ambient Temperature

Environmental concerns have prompted researchers to focus on the development of alternative building materials like geopolymer concrete. However, their implementation requires curing beyond 60°C, which limits their application on building sites. This study aims to design a geopolymer concrete at room temperature (30 ± 5°C) in a laboratory in Burkina Faso using a metakaolin-based geopolymer binder activated by an alkaline solution of NaOH and natural aggregates. Portland cement type CEM I 42.5 was used by mass substitution (0 to 25%) of metakaolin to promote curing at ambient temperature. The samples were cured for 7 to 28 days and characterized for physical, mechanical, and durability properties. The results showed that the incorporation of 0 to 20% cement significantly improved the compressive strength from 9.9 to 30.5 MPa and the tensile strength from 1.2 to 2.2 MPa. However, Portland cement has various effects on the durability of geopolymer concrete. It reduces the porosity accessible by water from 15 to 13% and decreases the resistance to acid attack by increasing the mass loss from 2 to 7%. This confirms that common concrete types C20/25 or C25/30 can be casted using geopolymer concrete on the sites in Burkina Faso once their durability is confirmed. Doi: 10.28991/CEJ-2023-09-07-04 Full Text: PDF

Performance of Mortars Made Using Ternary Binders with Addition of Slag, Fly Ash and Limestone Exposed to a Real Environmental Condition Compatible with Exposure Class XC3.

The use of eco-friendly cements prepared with ternary binders could contribute to improving the sustainability of cement production. However, their use for manufacturing commercial cements is very low, at least in Spain. The purpose of this research is to study the behavior in the long term of mortars made with ternary binders which incorporated ground granulated blast furnace slag, fly ash, and limestone, exposed to environmental conditions compatible with the specifications of exposure class XC3 of the Eurocode 2, compared to mortars without additions and mortars with binary binders. The exposure station was placed in an underground floor of a building used as a garage with circulation of vehicles and moderately high CO2 concentration. The ternary and binary binders verified the prescriptions of cement type CEM II/B. The microstructure was characterized using mercury intrusion porosimetry and electrical resistivity. Water absorption, diffusion coefficient, carbonation depth, mechanical strengths, and ultrasonic pulse velocity were determined. A loss of microstructure refinement with time was noted for all the analyzed binders, probably related to the development of carbonation and drying shrinkage. The binary mortars with slag and fly ash and the ternary binder which combined them showed the best mechanical performance at 250 days.

Effects of a Real Exposure Class XC4 Mediterranean Climate Environment in the Behavior of Mortars Made Using Ternary Binders with Addition of Slag, Fly Ash and Limestone.

For improving the contribution of the cement industry to mitigate global warming, many strategies have been put into practice, such as the use of eco-friendly cements with the incorporation of additions substituting clinker. Nevertheless, the use of ternary binders for the production of commercial cements is still reduced, particularly in Spain. The purpose of this research is to characterize the long-term influence produced by the exposure to a real in situ inland Mediterranean climate condition in the pore network, parameters related to durability and mechanical performance of mortars made with ternary binders, which incorporated limestone, fly ash, and ground granulated blast-furnace slag, in comparison with mortars without additions and binary blended mortars. The site verified the specifications of exposure class XC4 of Eurocode 2. The ternary and binary binders accomplished the prescriptions of cement type CEM II/B. The pore network was studied with mercury intrusion porosimetry and electrical resistivity. Water absorption, diffusion coefficient, carbonation depth, ultrasonic pulse velocity, compressive and flexural strengths have been determined. The exposure to the environment produced after 250 days an increase in porosity, a loss of pore refinement, a rise of the carbonation depths, and a reduction in the mechanical strengths, highlighting the better overall performance of ternary mortar with both fly ash and slag.

Microstructure, Durability and Mechanical Properties of Mortars Prepared Using Ternary Binders with Addition of Slag, Fly Ash and Limestone

In order to improve the contribution to sustainability of cement production, several strategies have been developed, such as the incorporation of additions as clinker replacement. Regarding the production of commercial cements with additions, those made with binary binders are mostly produced. However, the use of ternary binders for manufacturing commercial cements is still very low, at least in Spain, and they could also be an adequate solution for producing eco-friendly cements. The objective of this research is to study the effects in the long term produced by ternary binders which combine the additions of blast furnace slag, fly ash and limestone in the microstructure, durability and mechanical performance of mortars, compared to mortars without additions and mortars made with binary binders. The ternary and binary binders accomplished the prescriptions for a cement type CEM II/B. The microstructure was characterized using mercury intrusion porosimetry, electrical resistivity and differential thermal analysis. Absorption after immersion, diffusion coefficient, mechanical strengths and ultrasonic pulse velocity were studied. The best performance was noted for ternary binder with both slag and fly ash, probably produced by the synergetic effects of slag hydration and fly ash pozzolanic reactions. These effects were more noticeable regarding the compressive strength.

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.

INTRODUCTION TO THE DEVELOPMENT OF A HYDRAULIC ROAD BINDER BASED ON MINERAL COAL BOTTOM ASH

The use of natural aggregates with suitable characteristics for road construction presents in some regions a real problem of availability or cost related to transport. However, the resources in place, which are naturally unusable, can be used after treatment with Hydraulic Road Binders (HRB). In this study, we propose to valorize the mineral Coal Bottom Ash (CBA), a residue from the combustion of the SONICHAR power station in Niger, as the main component of an HRB.After a physical, chemical and mineralogical characterizationof the coal bottom ash, several proportions of the CBA powder and a cement type CEM I 42.5 were studied. Compression tests were carried out at 07, 28, 56 and 90 days to determine the class of the binder corresponding to the mixture selected.The performance of the HRB thus obtained was evaluated on two types of weakly clay soils (IP <= 12, NF P 94-051), having an initially insufficient CBR. The 3% treatment of this product made the two aforementioned soils suitable for use as a base layer.

Manufacturing of cast in situ ultra high performance fibre reinforced concrete (uhpfrc) - Workability, Tensile and Compressive Strength

The aim of this article is to share on the manufacturing process of Ultra High Performance Fibre Reinforced Concrete (UHPFRC) without heat curing or steam curing, hence, it makes UHPFRC possible to be used for in situ application. The common materials used in numerous previous studies were used in this work to produce UHPFRC: Cement type CEM I, fine sand, silica fume, water and third generation high range water reducer. Three tests were conducted, i.e. Compression test and slump flow test and tensile test. The targeted slump flow is in the range of 600 mm to 750 mm, minimum targeted compressive strength and tensile strength test is 115 MPa and 10 MPa, respectively. In addition, the UHPFRC must exhibit strain hardening properties. As a result, this study proposes the mix proportion of the above mentioned material used to produce UHPFRC which is suitable to be utilized for in situ application.

EFINITION OF DEFORMATION OF FINE-GRAINED CONCRETE ON THE BASIS OF SULPHATE-RESISTANT PORTLAND CEMENT

Introduction. The possibility of determining the relative deformations of fine-grained concretes based on sulfate-resistant cement was formulated by testing samples of gypsum-cement-sand mixture in distilled water in accordance with the requirements of the Vietnamese standard TCVN 6068:2004. Objective - to determine the deformations of fine-grained concrete because of sulfate-resistant Portland cement in accordance with the requirements of the TCVN 6068:2004 standard to assess its resistance to corrosion in an aggressive sulfate medium. Materials and methods. To obtain a gypsum-cement-sand mixture, a finely disintegrating binder was used, consisting of sulfate-resistant Portland cement of the type CEM I CC 42.5 N produced by the “Tam Diep” plant with the addition of natural gypsum produced by the company “Dinh Vu”. Quartz sand was used as fine aggregate. All raw materials used were native to Vietnam. Grinding fineness, normal cement density, setting time, the uniformity of the volume change and the activity of sulfate-resistant Portland cement were determined according to GOST 30744-2001; deformations of samples from gypsum-cement-sand mixtures - according to the Vietnamese standard TCVN 6068:2004. Results. Investigated the relative increase in the volume of samples of gypsum-cement-sand mixture based on sulfate-resistant Portland cement and natural gypsum as a result of their testing in distilled water according to the standard TCVN 6068:2004. Conclusions. Found that the average value of the relative deformation of the prism samples of concrete as a result of a 14-day test in distilled water was 0.037 %, which is within the acceptable value of 0.04 % in accordance with the requirements of the Vietnamese standard TCVN 6067:2004. Therefore, sulfate-resistant Portland cement type CEM I CC 42.5 N produced by the “Tam Diep” plant is a promising material as a binder for the preparation of corrosion-resistant concrete. The increase in the mean values of the relative deformations of the gypsum-cement-sand prism specimens after the 28-day and 60-day of testing, compared to the results of the 14-day test, can be explained by a slightly increased content of tricalcium aluminate in the studied cement.

Properties of blastfurnace cements (CEM III/A, B, C) based on Portland cement clinker, blastfurnace slag and cement kiln dusts

This study has examined the effectiveness of characteristically different cement kiln dusts (CKDs) as a partial replacement for the ground granulated blastfurnace slag (GGBFS) in the development and production of three types of blastfurnace cements (CEM III/A, B, C) according to the standard EN 197-1.27 CEM III cement blends, 9 blends per type of cement, i.e., CEM III/A, CEM III/B and CEM III/C, were prepared in the laboratory mill from industrial starting materials (Portland cement clinker, gypsum, GGBFS, CKDs). The addition of gypsum as the setting regulator was fixed at 4 mass % in all blends studied. The content of both CKDs (cement clinker dust and cement filter dust) as slag replacements was 4 mass % in all CKD blends studied. The ordinary Portland cement (OPC) type CEM I 42.5N was used as the control cement. The results have shown that the chemical composition and chemical and physical properties of prepared CEM III/A, B, C cement blends meet the EN 197-1 requirements. Strength development in these cement blends is obviously related to the Portland cement clinker-to-GGBFS ratio. When compared to OPC, the blastfurnace cement developed lower compressive strength at early ages, but equal or higher at later ages in more cases, i.e., all 9 CEM III/A and 7 CEM III/B cement blends meet, while no CEM III/C cement blend meets the EN 197-1 requirements for standard compressive strength Class 42.5N. From the perspective of strength, the presence of the cement clinker dust is more effective than that of the cement filter dust due to their different chemical and mineralogical compositions.

Geotechnical parameters of loess-cement mixture for construction of compacted soil-cement cushion

Soil-cement cushions are compacted and stabilized layers of the soil base, built under the foundation. Usually, they are constructed with local soil from the excavation, mixed with Portland cement. In Bulgaria, this soil improvement technique has been applied in foundation works in collapsible loess ground, aiming to replace a part of the collapsible layer, to increase the bearing capacity of the soil base, and/or to play a role of engineering barrier against migration of harmful substances in the geoenvironment. A multi-barrier near-surface short-lived low- and intermediate-level radioactive waste repository is under construction in Bulgaria. A loess-cement cushion beneath repository cells is going to be built by in-situ compacted mixture of local loess and Portland cement. Based on the results from classification and physico-mechanical tests of a set of loess-cement mixtures, it was proposed optimum cement content of the loess-cement cushion beneath the radioactive waste repository to be 5% of Portland cement. The present paper aims to assess the following geotechnical parameters of the selected loess-cement mixture after proper curing: unconfined compressive and flexural strength; shear strength parameters; static and dynamic elastic constants; and hydraulic conductivity. The results obtained prove that the mixture prepared at Wopt and ρds of local loess and 5% (by the dry weight of soil) of Portland cement type CEM I 42.5 N – SR 5 possesses strength and deformation characteristics that completely meet the design stress-strain requirements to the soil-cement cushion beneath the repository foundation.

Briefing: Low-alkali cements as inhibitors of alkali–silica reaction

In this study, a compositional parameter, such as the maximum allowable total alkali content of cement (Matac) is proposed to identify the non-CEM I cements for their use as inhibitors of alkali–silica reaction in concrete. The Matac values for different types of Italian non-CEM I cements (cement type CEM III and CEM IV) were calculated using the authors' previously published experimental results. The Matac value is found to change significantly with the type of cement considered (blast furnace cement, pozzolanic cement made from coal fly ash or natural pozzolana). For cements of the same type (pozzolanic cements made with different natural pozzolanas), very similar Matac values are obtained. It is also demonstrated that the Matac value calculated for a CEM I cement is congruent with the limit of 0·6% as Na2Oeq commonly specified for the total alkali content of low-alkali Portland cements.

Accelerated Leach Test for Low-level Radioactive Waste Forms in the Hungarian NPP Paks

An accelerated leach test method was used for low-level radioactive waste forms in the Hungarian NPP Paks. These experiments were performed using cylinders prepared form Hungarian cement type CEM I 32,5 LH and CEM III/B 32, N-LH/SR. Each cylinder was made using cement or cement plus additive using radioactive waste water. The cemented radioactive material was evaporator bottom residue or sludge as well as evaporator cleaning acid solution, spent ion exchange resin, decontamination solution from NPP Paks, containing 134Cs, 137Cs and 60Co as main radioactive components. Leach tests were performed according to ASTM C 1308-08 standard. A computer program (ILT15) associated with the accelerated leach test was developed based on the ASTM C 1308-08 standard. Literature test and measured leaching data were analyzed to assess whether the model for diffusion from a finite cylinder describes leaching from cement based waste forms. In this paper some of the experimental and modeling work used to validate the test method are presented.

A new meta-model to calculate carbonation front depth within concrete structures

Carbonation processes cannot be ignored as regards durability and service-life of new concrete structures, and their correct understanding and quantification are essential for maintenance and repair works on existing structures. This paper initially presents a new meta-model developed to calculate carbonation front depth based on the analytic solution of Fick’s first law. The only input data required by this non numerical model are: (i) material variables (concrete mix design, maximum nominal aggregate size, cement type, and chemical composition of cement type CEM I and cement density); (ii) technological parameters (initial curing period (tc)); (iii) environmental parameters (ambient temperature (T), relative external humidity (RH) and CO2 concentration in the air ([CO2]ext)). Consequently, this model is fully suitable for the prediction of carbonation depth in the case of new reinforced concrete structures, for which these required parameters are well-known. The meta-model is validated using data from the literature on short and long-term natural carbonation exposure conditions. Most of the experimental data concern CEM I, CEM II, CEM III cement types, and CEM I additives (fly ash (FA)) with various water to cement (W/C) ratios and tc. The meta-model is also compared with two already available models: Papadakis’ model and Yang’s model. The three model predictions are compared with the corresponding values found in the literature. The results confirm that the prediction of the new meta-model proposed here for estimation of carbonation depth is the most accurate in every case.

Variation of the surface chromatic properties of exposed concrete façades treated with anti-graffiti products

The research analyses the variation of the surface chromatic properties, hue and brightness, sustained by the Portland cement mortar support, due to the application of anti-graffiti protective treatments. The test specimens were digitally analysed using a methodology based on the RGB model, which resulted in the image histogram values of each test specimen treated. The same mortar type without protection was used as the base to quantify the modification. Surface chromatic variation is determined by the type of anti-graffiti treatment used and by the base material on which it is applied. The result is that all the anti-graffiti products studied cause the variation of the supports’ hue and brightness, with the mortar made from grey Portland cement type CEM II/B-M(V-L) 32,5 N (Mb) being the one with less variation of its surface chromatic characteristics once treated. In addition, the fluorinated acrylate component (A4) causes the smalles deviation of the absolute hue and brightness values obtained from the samples analysed.

POSSIBILITIES TO USE TEXTILE CORD WASTE FROM USED TIRES FOR CONCRETE

The goal of the study was to determine the effect of waste tire cord yarn with attached rubber particles on the properties of concrete made of different types of cement (Portland cement without additives – CEM I, Portland cement with limestone additive – CEM II). The filament waste (added at 0%, 2%, 4%, 6%, 8%, and 10% of the amount of fine aggregate) is water absorbing textile fibre additive with rubber particles, therefore a bigger amount of water is required to prepare the concrete mixture. With waste additive, the density and compressive strength of concrete reduces, but water absorption increases. The forecasted freeze-thaw resistance of concrete with cement type CEM I and recycled tire cord increases and slightly reduces when cement type CEM II is used, however retains similar resistance in about 1000 freeze-thaw cycles. The coefficient of thermal conductivity decreases approx. 35%, when 10% of recycled tire textile cord is added to concrete mixture.

Effect of silica fume fineness on the improvement of Portland cement strength performance

This paper presents both a study on the effect of silica fume (SF) fineness on the pozzolanicity of blended cement and a method for improving coarse SF performance in making high-strength and high-performance concrete. The coarse SF, having a 45μm sieve residue of 32.11%, yields a low pozzolanic reaction. In order to enhance its quality, the coarse SF was ground until the average particle size was reduced to a 45μm sieve residue of 4.13% and 0.98%. It was then mixed with Portland cement type CEM I 52.5 N-SR 3 by a weight of 25% to determine the strength activity index for it to be used to produce high-performance concrete.The pozzolanic reaction and quantitative influence of SF fineness on the mechanical strength in the SF containing composite cement system were examined in detail. XRF results indicated that reactive SiO2 content has a clear influence on pozzolanic performance, though not as important as the SF grain size. Several methods, including the pozzolanicity test (EN 196-5:2011), chemical analysis (XRF) and strength activity index techniques, were used comprehensively for evaluation of the SF containing composite cement system.The results suggest that the SF with high fineness is suitable for use in making CEM II/A–D cement in percentages of SF lower than 10%, according to the European Standard EN 197-1:2011 in producing a good quality, high-strength and high-performance concrete.

ASSESSMENT OF THE LEACHABILITY AND MECHANICAL STABILITY OF MUD FROM A ZINC-PLATING PLANT AND WASTE ZEOLITE BINDING WITH PORTLAND CEMENT

The study has examined the immobilization of mud from a zinc-plating plant and waste zeolite materials with Portland cement type CEM I. Determination of leachability was assessed by NEN 7345 leaching test. The mechanical stability of immobilized samples was tested by measuring compressive and flexural strength. The samples with the addition of mud showed high mobility of zinc ions with leachability index values below criteria limit. With the addition of waste zeolite in cement-mud system, zinc has become less mobile with greater leachability index. According to diffusion model, controlling mechanism for leaching of zinc is a wash-off (except for the sample with the addition of 5 % of mud). For samples with lower addition of waste zeolite, leaching mechanism is diffusion, whereas at higher additions, the leaching mechanism is wash-off. Identification of forming hydrated products was carried out using Fourier transform infrared technique.

Assessment of Natural Radioactivity Levels of Cements and Cement Composites in the Slovak Republic

The radionuclide activities of 226Ra, 232Th and 40K and radiological parameters (radium equivalent activity, gamma and alpha indices, the absorbed gamma dose rate and external and internal hazard indices) of cements and cement composites commonly used in the Slovak Republic have been studied in this paper. The cement samples of 8 types of cements from Slovak cement plants and five types of composites made from cement type CEM I were analyzed in the experiment. The radionuclide activities in the cements ranged from 8.58–19.1 Bq·kg−1, 9.78–26.3 Bq·kg−1 and 156.5–489.4 Bq·kg−1 for 226Ra, 232Th and 40K, respectively. The radiological parameters in cement samples were calculated as follows: mean radium equivalent activity Raeq = 67.87 Bq·kg−1, gamma index Iγ = 0.256, alpha index Iα = 0.067, the absorbed gamma dose rate D = 60.76 nGy·h−1, external hazard index Hex = 0.182 and internal hazard index Hin was 0.218. The radionuclide activity in composites ranged from 6.84–10.8 Bq·kg−1 for 226Ra, 13.1–20.5 Bq·kg−1 for 232Th and 250.4–494.4 Bq·kg−1 for 40K. The calculated radiological parameters of cements were lower than calculated radiological parameters of cement composites.