Ternary Cement Research Articles

Optimization and Hydration Mechanism of Ecological Ternary Cements Containing Phosphogypsum

Ecological ternary cements (ECP) were prepared with powders of phosphogypsum (PG), fly ash (FA) and Portland cement (PC). The evolution mechanism of the hydration product structure was characterized through macro and micro experiments. The thermodynamic characteristics of the solid phase, solid solution phase and aqueous solution in the process of hydration about the phosphogypsum–fly ash–cement ternary cementitious system were studied based on the Gibbs-free-energy C-S-H thermodynamic model and GEM-Selektor software and compared with the experimental results. The results show that, in the hydration reaction, the thermodynamic interaction between the mineral single-phase and hydration products plays an important role in the spatio-temporal distribution of ions in the cementitious system. The values of CaO, SiO2H and H2Ohyd gradually increased with the increase in the Ca/Si ratio, while the values of CaOext and H2OOH showed a positive proportional relationship and the values of SiO2H and SiO2 showed an inverse proportional relationship. GEM-Selektor accurately simulated the total amount of AFt and AFm mineral phases, and quantitatively analyzed the correlation of complex ion groups about C-S-H gels and C3S.

Effects of Na2CO3 on engineering properties of cement–limestone powder–slag ternary blends

Cement–limestone powder–slag ternary blends are construction materials that can significantly reduce carbon emissions and have a high potential for broad applications. This study investigated the effects of Na2CO3 on the engineering properties, hydration, and hydration products of cement–limestone powder–slag ternary blends. The compressive strength, ultrasonic velocity, and surface resistivity of ternary cement blends were determined. The exothermic process of paste hydration was monitored for 7 d. Furthermore, the hydration products at different stages were characterized and analyzed by X-ray diffraction, thermal gravimetry analysis, and Fourier transform infrared spectroscopy. Results for the heat of hydration indicated that Na2CO3 accelerated the early hydration of the ternary blends. Adding Na2CO3 improved the 1 d compressive strength and surface resistivity of the cement paste. As the hydration progressed, Na2CO3 limited the compressive strength and ultrasonic velocity development of the ternary cement blends in the later stages. With an increase in the content, Na2CO3 reduced the calcium hydroxide inside the cement and increased the crystallinity of calcium carbonate. This study addresses the gap in existing literature regarding the use of Na2CO3 in cement–limestone powder–slag ternary blends. Furthermore, it presents new ideas for producing cement materials with a low carbon footprint and high durability.

Evaluation of use of marble and granite cutting waste to the production of self-compacting concrete

Due to the continuous storage of large quantities of marble and granite waste (MGW), generated during the processing of ornamental stones, researchers have been using this material in a sustainable way to reduce its adverse impacts on the ecosystem. In this study, the main objective was to evaluate the effect of using MGW on mechanical properties and durability of self-compacting concretes (SCC), as part of the fines required to ensure self-compacting characteristics. Also, it was investigated this material as a new possibility in the composition of a ternary cement modality. For this, an experimental program was developed with four SCC mixtures, in which tests were performed to determine the properties in the fresh state, hardened properties, durability, and microstructural analyses. The test results indicated that all mixtures complied the self-compacting requirements and the incorporation of MGW contributed to the stabilization of the concretes. The mixture with CPV-ARI cement and MGW incorporated as fine in the concrete, and the mixture with MGW both incorporated as fines in the concrete and in the composition of ternary cement CP-MMG did not present statistically significant differences for some results of the mechanical properties. Besides, these mixtures provided improvements and similar results of some durability and microstructural tests, respectively. In general, the different possibilities of utilization of the residue proposed in this study, generate an appropriate destination for MGW and propose a viable alternative for the reduction of clinker consumption in cement production.

Progress in the influence of recycled construction and demolition mineral-based blends on the physical–mechanical behaviour of ternary cementitious matrices

The serious technical and environmental problems associated with the management of construction and demolition wastes (CDW) have led to a worldwide growing interest in the recycling of that waste stream as secondary raw material for sustainable building applications.This research work investigates the physical and mechanical behaviour of mortars made with ternary cements containing 7% of a binary recycled CDW mixture comprising the fine fraction (<5 mm) of recycled concrete waste (both siliceous and calcareous nature) in combination with recycled laminar glass in three different proportions (1/1, 1/2, and 2/1, respectively). To this end, the chemical composition and fineness of the anhydrous ternary cements were analysed, as well as their behaviour in paste and mortar matrices, in both fresh and hardened states, verifying the requirements established by the applicable standards.The results attest to the viability of using these ternary cements, as their performance is comparable to that of an ordinary Portland cement (OPC), without evidencing any significant dependence on the glass content. The compressive strength values decrease by 7–8% with respect to that of the OPC mortar, revealing the prevalence of the filler effect over the pozzolanic reaction. The ternary cements analysed in this study met the chemical, physical and mechanical requirements for the elaboration of future eco-efficient cements.

Incidence of recycled aggregates and ternary cements on the compressive strength and durability of ecological mortars

This research presents the effect of substituting natural aggregates by recycled aggregates and cement blended with limestone by coal ashes on the compressive strength and durability properties of an ecological mortar. Firstly, the industrial wastes (recycled aggregate from concrete and coal ash) were characterized using physical, chemical, and mineralogical techniques such as x-ray diffraction (DRX), particle size distribution (PSD), and electronic scanning microscopy (SEM). Secondly, the maximum substitution of blended cement for coal ash was defined based on the compressive strength in order to obtain a ternary cement. Subsequently, the mortars with ternary cement and different dosages of recycled aggregate were made, these mortars were evaluated through compressive strength and sulfate attack resistance (durability). The results found show that the inclusion of these by-products improved mechanical properties due to the chemical affinity between the recycled aggregates and the ashes. The contents of old adhered mortar in recycled aggregates made more susceptible mixtures to be attacked by the magnesium sulfates. This phenomenon was studied through SEM and sulfate attack test. Finally, the expansion exhibited by the samples manufactured with recycled aggregate and coal ash did not reach the limits for the initial degradation of the material. That is, ternary cements, such as those used in this research, when mixed with recycled aggregates, allow the production of ecological concretes and mortars with excellent mechanical behavior and resistance to sulfate attack.

Mechanical Performance of Portland Cement, Coarse Silica Fume, and Limestone (PC-SF-LS) Ternary Portland Cements.

Ternary Portland cements composed of coarse silica fume (SF), limestone (LS), and Portland cement (PC) can afford some environmental advantages by reducing the clinker content in Portland cements. These cements will help to reduce the clinker factor target from 0.78 to 0.60 by 2050 with the aim to be climate neutral. Silica fume (SF) possesses pozzolanic properties that enhance mechanical strength and durability. By contrast, limestone powder has three main outcomes, i.e., filler, dilution, and chemical effects. The first reduces porosity and refines the microstructure of mortars and concretes. The second decreases the amount of hydration products and increases the porosity; the third one promotes the appearance of carboaluminates and reduces porosity. This paper covers the mechanical properties of Portland cement-limestone-coarse silica fume ternary cements, and its synergetic mechanism. Compressive and flexural strength of mortar at 2, 7, 14 and 28 days was performed. Coarse silica fume has a minor contribution on the nucleation effect compared to ground limestone at early ages. The nucleation and filler effects, at early ages, are less pronounced in coarse and very fine limestone powder. The highest compressive strength at 28 days is reached with the lowest content of coarse silica fume (3%). Mortar mixes made with a high level of limestone presented a delay in the compressive strength development.

Durability of Construction and Demolition Waste-Bearing Ternary Eco-Cements.

In recent years, the development of ternary cements has become a priority research line for obtaining cements with a lower carbon footprint, with the goal to contribute to achieve climate neutrality by 2050. This study compared ordinary Portland cement (OPC) durability to the performance of ternary cements bearing OPC plus 7% of a 2:1 binary blend of either calcareous (Hc) or siliceous (Hs) concrete waste fines and shatterproof glass. Durability was measured further to the existing legislation for testing concrete water absorption, effective porosity, pressurized water absorption and resistance to chlorides and CO2. The experimental findings showed that the 7% blended mortars performed better than the reference cement in terms of total and effective porosity, but they absorbed more pressurized water. They also exhibited lower CO2 resistance, particularly in the calcareous blend, likely due to its higher porosity. Including the binary blend of CDW enhanced chloride resistance with diffusion coefficients of 2.9 × 10−11 m2 s−1 (calcareous fines-glass, 7%Hc-G) and 1.5 × 10−11 m2 s−1 (siliceous fines-glass, 7%Hs-G) compared to the reference cement’s 4.3 × 10−11 m2 s−1. The siliceous fines-glass blend out-performed the calcareous blend in all the durability tests. As the mortars with and without CDW (construction and demolition waste) performed to similar standards overall, the former were deemed viable for the manufacture of future eco-efficient cements.

Durability aspects and mechanical strength of mortars containing glass powder and slag

The combination of glass powder (GP) with pozzolanic additions to replace clinker can develop new types of binders (ternary cement) with improved physical and mechanical properties, thereby enabling a reduction in consumption of clinker and natural resources, and the minimisation of the carbon dioxide emissions. In this context, the present work is an attempt to study the influence of GP with two different specific surface areas (Blaine) GP30 = 300 m2/kg and GP45 = 450 m2/kg, combined with slag, on the mechanical behaviour and durability of mortars. The mechanical properties were investigated using compressive and flexural strength tests. Aspects related to durability were examined as well by water-accessible porosity, capillary absorption and sorptivity tests. The replacement rate of cement by GP varied from 10 to 20% and the proportion of slag was fixed at 10%. The results showed that a binary mortar made with 20% GP45 replacement showed increases in 90 day compressive strength, while ternary mortar with 20% GP45 + 10% slag replacement gave the best result. The same trend is also valid for durability properties examined in this study. The combined use of GP and slag at 30% replacement levels seemed to perform better compared with using GP alone.

Hardening and Fresh State Behaviour of Ternary Cement for Marine Environments: Modification through Nanoadditives.

The use of nanomaterials to enhance the physical and mechanical properties and durability of cement materials in their hardened state has been studied for a long time in many investigations. In comparison, fewer studies focus on nanomaterials’ influence on the fresh state when the cement reaction starts. In addition, if we consider ternary blended cement (as those used for applications in marine environments), this has been rarely studied. Severe stresses in the marine environment require high durability, which is achieved by using pozzolanic additions, to the detriment of a rapid achievement of the properties. The addition of nanomaterials could contribute to increasing the durability and also accelerating the setting of the concrete. In this work, we performed a systematic and comparative study on the influence of adding graphene oxide (GO), nanosilica (NS), and microfibrillated cellulose (MFC) during the setting mechanisms of cement (CEM V/A suitable for concrete subjected to external attacks in marine environments) blended with fly ash and slag. Cement hardening was examined through setting time and rheology within mini-slump tests. The effect of nanoadditives on the cement hydration was analysed by heat flow calorimetry to evaluate the acceleration potential. Exploring the three nanoadditives on the same formulation, we could establish that the retention of mixing water significantly decreased workability for MFC. In contrast, NS increases the hydration of cement particles, acting as nucleation nodes and promoting supplementary cement hydrates (pozzolanic reactions) and accelerating setting time. Finally, GO showed a reduction in workability. We also investigated the dosage effects on mechanical behaviour at an early age and discovered an improvement even at low GO (0.006%) and NS (3%) dosages. We have also analysed the dosage effects on mechanical behaviour at an early age.

From composition to the microstructure and durability of limestone ternary blended cements: A systematic review

Limestone ternary cements (LTCs) have attracted significant research and commercial attention recently, for technical and environmental reasons. Standardisation of these cements is imminent under BS EN 197-5:2021. Detailed understanding of the hydration and microstructure evolution of LTCs from different alumina-rich supplementary cementitious materials exists in the scientific literature; improved reaction kinetics and additional phase assemblages refine the pore structure. However, understanding of the performance of LTCs under exposure conditions is less prevalent. In this contribution, the available data are reviewed in a way that allows stakeholders to appreciate the capabilities of the different compositions and their performance. The focus is a critical examination of the interplay between cement composition and microstructure and its effect on durability. It is demonstrated that LTCs offer a pathway for reducing the embodied carbon dioxide of concrete without compromising their performance. Resistance to chloride ingress, sulfate attack and alkali–silica reactions are significantly improved in a manner similar to binary cements. Compared with ordinary Portland cement, carbonation and freeze–thaw resistance are generally lower, but adequate air entrainment can offer an improvement in freeze–thaw resistance. The challenge to widespread adoption of LTCs is evidence of durability under field conditions. To this end, large-scale field trialling is recommended to gain understanding of the role of combined exposures on the durability and mechanical properties of LTCs.

Effect of calcium formate on the compressive strength, and hydration process of cement composite containing fly ash and slag

The replacement of Portland cement (PC) by fly ash (FA) or slag will cause low early age strength development of concrete. However, the addition of chemical additives can eliminate the well-known drawbacks above. The effect of calcium formate (CF) on the compressive strength development of ternary cement (containing FA and slag) was studied based on simplex centroid design in this paper. Results show that CF can be safely used to increase the strength of ternary cement composite. In addition, the influence of CF on the hydration process and microstructural features of PC and PC-FA/slag blends was investigated using isothermal calorimetry, X-ray diffraction, thermal analysis, and scanning electron microscopy. These results show that the addition of CF can enhance the strength of PC and PC-FA/slag blends at early curing ages, which is mainly because of a kind of calcium aluminate silicate hydrate called gismondine (CaAl2Si2O8·4H2O) and more formation of ettringite (AFt). Furthermore, at later ages of hydration, CF can promote the silicate reaction of PC and PC-FA/slag blends and accelerate the pozzolanic reaction of FA in order to improve the strength.

A new ternary composite steel rebar coating for enhanced corrosion resistance in chloride environment

This work reports a novel ternary cement polymer composite coating (CPFNIC) consisting of fly ash, nanoparticles, and inhibitor with enhanced corrosion protection for steel rebars in a chloride environment. Electrochemical impedance spectroscopy (EIS) measurements, polarization curves, salt spray test, scanning electron microscopy (SEM), and Confocal Laser Scanning Microscopy (CLSM) were used to understand the corrosion protection mechanism and for characterization of corrosion products. The results show that the new coating significantly delayed the onset of corrosion on rebars in aggressive chloride environments due to the synergistic contributions from the additives used. The electrochemical studies (open circuit potential and corrosion current) indicate a significantly improved corrosion performance of CPFNIC as compared to uncoated rebars. The potentiodynamic polarization results of CPFNIC coated rebars showed high corrosion potential, low corrosion current density, three order higher polarization resistance, and two-order lower corrosion rate than the uncoated rebar. The EIS measurements showed a significantly higher charge transfer resistance for the CPFNIC as compared to the uncoated rebar. The visual inspection and weight loss measurements in salt spray and chemical resistance tests of CPFNIC coated rebars corroborated its improved resistance in chloride environment. Our results suggest the benefits of ternary composite cementitious coating on rebars in enhancing the corrosion protection.

Vol4 num3-4 Ternary cements as a sustainable alternative in Civil Engineering

Construction industry is among the most polluting human activities, mainly due to CO2 emisions produced during portland cement manufacture. The cement production industry has incorporated byproducts of other industries, to produce a more sustainable material. This would be due to the decrease of raw materials, treat byproducts in a safe way, and improve the properties of the cement manufactured. The durability of the structures would also be improved. The main problem is that the properties are not good in the short term. In the last years there have been many efforts regarding the incorporation of two or more aditions, because they produce a synergic effect that improve the properties of concrete or mortars. This type of cements has been called ternary cements In this work ternary cements have been produced using three different aditions: ground granulated blast furnance slag, and fly ashes, as active aditions, and limestone filler as a non-active adition. The total amount of addition is limited to a 35% maximum, for all of them together, as it is stated in the instruction for structural concrete, EHE-08. 35% is the maximum adition allowed for concrete production, and always added to ordinary portland cement. Mechanical properties and some durability parameters have been studied in the short terms for both a ternary cement and the results have been compared with a binary cement.The results are promising, and show a good behavior, what means that these cements could be safely used in real structures.

Ternary cements as a sustainable alternative in Civil Engineering

Construction industry is among the most polluting human activities, mainly due to CO2 emisions produced during portland cement manufacture. The cement production industry has incorporated byproducts of other industries, to produce a more sustainable material. This would be due to the decrease of raw materials, treat byproducts in a safe way, and improve the properties of the cement manufactured. The durability of the structures would also be improved. The main problem is that the properties are not good in the short term. In the last years there have been many efforts regarding the incorporation of two or more aditions, because they produce a synergic effect that improve the properties of concrete or mortars. This type of cements has been called ternary cements In this work ternary cements have been produced using three different aditions: ground granulated blast furnance slag, and fly ashes, as active aditions, and limestone filler as a non-active adition. The total amount of addition is limited to a 35% maximum, for all of them together, as it is stated in the instruction for structural concrete, EHE-08. 35% is the maximum adition allowed for concrete production, and always added to ordinary portland cement. Mechanical properties and some durability parameters have been studied in the short terms for both a ternary cement and the results have been compared with a binary cement.The results are promising, and show a good behavior, what means that these cements could be safely used in real structures.

Optimization and Hydration Mechanism of Ecological Ternary Cements Containing Phosphogypsum

Optimization and Hydration Mechanism of Ecological Ternary Cements Containing Phosphogypsum

Statistical Modelling of the Compressive Strength of Mortar Based on Cement Blended with Mineral Additions by the Method of Experimental Design

This experimental study aims to study the mechanical behaviour of a mortar based on cement blended with mineral additions (pozzolana, limestone and slag), knowing that the mechanical strength of a mortar is closely related to its composition. The use of the three mineral additions simultaneously, presents a high number of factors affecting the mechanical resistance and requires a very large number of experiments and the obtained data analysis becomes much more complex. In order to optimise the number of tests and to achieve a such satisfactory analysis, a statistical approach known as an "experimental design" was used. The experimental methodology has been established to assess the compressive strength of mortars at 2, 7, 28 and 60 days, by the elaboration of an experimental design for a set of cement mixtures, the level of the three additions (factors), slag, limestone and pozzolana at rates varying from 0% to 35%, provided that a fixed dosage of 35% is maintained for all combinations to form a binary, ternary and quaternary cement in accordance with cement standard requirements CEM II/B. This statistical approach allowed us to evaluate by a numerical analysis the effect of each addition alone as well the meaning of the double or triple interaction resulting from the association of two or three additions at a time. In addition, it has enabled us to establish a representative model that permitted to estimate and predict the mechanical behaviour of any composition in the experimental program with tolerable errors. The obtained results lead to a satisfactory numerical modeling of the compressive strengths, in particular at the age of 28 days, with a trend curve of a an acceptable determined coefficient of R2 equal to 0.87.

Evaluation of rheological and durability characteristics of sugarcane bagasse ash and rice husk ash based binary and ternary cementitious system

Implementation of biomass based power plants is substantially increased worldwide, and hence large quantity of agro-waste ashes is disposed as waste. The reuse of agro-waste ashes as supplementary cementitious materials helps to solve problems associated with intensive carbon emission from cement plants and the disposal of agro-waste ashes. Although earlier studies are reported on the use of sugarcane bagasse ash and rice husk ash as a pozzolan in concrete, studies on their combined use in the production of ternary cement are highly limited. Hence, the present study focuses on the performance evaluation of the sugarcane bagasse ash and rice husk ash based ternary blended cementitious system. The performance of the ternary blended concrete is also compared with sugarcane bagasse ash based binary blended concrete. Rheological characteristics, compressive strength, rapid chloride penetration test, water sorptivity index, and porosity of the blended concrete is investigated. The yield stress, plastic viscosity and consistency index are increased with the increase in the addition of sugarcane bagasse ash and rice husk ash. The highest compressive strength is observed for ternary blended concrete with 10% bagasse ash and 5% rice husk ash, followed by blended binary concrete with 20% bagasse ash. The decrease in portlandite was evidently observed for binary and ternary blended samples with the addition of bagasse ash and rice husk ash using X-ray diffractogram and thermal analysis. Reduction in chloride permeability, water sorptivity index and porosity was observed for agro-waste ashes blended concrete than control concrete.

Waste press mud in enhancing the performance of glass powder blended cement

Due to the significant environmental damages caused by cement production, the use of blended cement has gained greater attention. This paper explores the novel use of solid waste from the sugar industry namely press mud (PM) and waste glass powder (GP) as cement replacement in ternary blended cement. The ternary blended cement consists of 20% GP and the influence of PM at various cement replacement levels between 5 and 20% was investigated. The fresh, strength, sorption, morphological, and thermogravimetric characteristics of the ternary blended cements were evaluated. The results showed that the incorporation of 10% and 15% of PM could improve the consistency, early and later age strengths, exhibit similar flexural strength and reduce the sorptivity of the GP binary cement mortar. The morphologies were also observed to have improved by reducing of voids, facilitating reaction of GP particles, and contributing additional hydration products. This was confirmed by thermogravimetric analysis results, whereby more hydration products were found in cement-GP-PM ternary cement pastes. In overall, the suitable integration of PM could improve the properties of ternary blended cement containing GP while reducing the usage of cement.

Influence of low-grade materials as clinker substitute on the rheological behavior, hydration and mechanical performance of ternary cements

This study aims to evaluate the influence of low-grade local materials as clinker substitute in ternary cements, with calcined clay (30 wt%) and limestone (15 wt%), also known as LC³ cements. A coal mining waste (based on 35 wt% kaolinite content, AR) and a dolomitic limestone (LLS) were compared to more pure materials such as natural clay (constituted by 83% kaolinite content, NC) and high-grade limestone (HLS), respectively. LC³ cements were compared to reference system (45 wt% quartz filler instead of limestone and calcined clays), as well as a fly ash blended cement (40 wt% fly ash, 40FA). Hydration kinetics, water demand, plastic viscosity, and yield stress were evaluated in a fresh state. The fineness of the calcined clays and limestone had a greater impact on the water demand and thixotropy of the pastes than their mineralogical compositions. However, the higher kaolinite content of NC led to higher pozzolanic activity, greater formation of carboaluminate type phases, and compressive strength than LC3 cements with AR. The HLS and LLS had similar impact on the proprieties assessed despite their different mineralogical composition. Thus, both low-grade materials are feasible as raw materials for the production of LC³ type cements with similar performance when compared to conventional cements.

Composite cements: synergistic effects of particle packing and pozzolanicity

The production of cement is a carbon dioxide-intensive process. Replacing ordinary Portland cement (OPC) with industrial by-products can bring down the carbon footprint associated with cement production. Various industrial residues are currently used as alternative cementitious materials in this regard. However, developing a low carbon dioxide composite cement with different pozzolans alters the packing density, which influences its properties. Although studies have been conducted on the use of fly ash and slag at lower cement replacement levels, studies on the packing density and strength of ternary and quaternary composite cements with higher replacement levels are limited. In this study, fly ash, blast-furnace slag, ultra-fine fly ash and ultra-fine slag are used as a partial replacement for cement in various proportions. Out of the 51 mixtures tested in the study, 11 combinations were selected, based on the maximum packing density, for further investigations on fresh and hardened properties to arrive at the best trade-off between cement reduction and desired properties. The early-age strength is influenced by the packing density of composite cements, whereas the later-age strength is found to be highly governed by the amount of OPC and the pozzolanic potential of the industrial by-products.