Simulation of a temperature rise in concrete incorporating fly ash or slag

Granulated slag from metal industries and fly ash from the combustion of coal are among the industrial by-products and have been widely used as mineral admixtures in normal and high strength concrete. Due to the reaction between calcium hydroxide and fly ash or slag, compared with Portland cement, the hydration of concrete containing fly ash or slag is much more complex. In this paper, by considering the producing of calcium hydroxide in cement hydration and the consumption of it in the reaction of mineral admixtures, a numerical model is proposed to simulate the hydration of concrete containing fly ash or slag. The heat evolution rate of fly ash or slag blended concrete is determined from the contribution of both cement hydration and the reaction of mineral admixtures. Furthermore, a temperature rise in blended concrete is evaluated based on the degree of hydration of cement and mineral admixtures. The proposed model is verified with experimental data on the concrete with different water-to-cement ratios and mineral admixtures substitution ratios.     

A model predicting carbonation depth of concrete containing silica fume

Silica fume (SF) has been used since long as a mineral admixture to improve durability and produce high strength and high performance concrete. Due to the pozzolanic reaction between calcium hydroxide and silica fume, compared with ordinary Portland cement, the carbonation of concrete containing silica fume is much more complex. In this paper, based on a multi-component concept, a numerical model is built which can predict the carbonation of concrete containing silica fume. The proposed model starts with the mix proportions of concrete and considers both Portland cement hydration reaction and pozzolanic reaction. The amount of hydration products which are susceptible to carbonate, such as calcium hydroxide (CH) and calcium silicate hydrate (CSH), as well as porosity can be obtained as associated results of the proposed model during the hydration period. The influence of water-binder ratio and silica fume content on carbonation is considered. The predicted results agree well with experimental results.     

A multi-phase kinetic model to simulate hydration of slag–cement blends

Ground granulated blast furnace slag, which shows cementitious behavior (latent hydraulic activity) and pozzolanic characteristics (reaction with lime), has been widely used as a mineral admixture in normal and high strength concretes. Hydration of slag–blended cement is much more complex than that of ordinary Portland cement because of the mutual interactions between the cement hydration and the slag reaction. This paper presents a kinetic hydration model for cement–slag blends. The proposed model analyzes the slag reaction separate from cement hydration by considering the production of calcium hydroxide in cement hydration and its consumption in slag reactions. The amount of free water and the amount of calcium hydroxide left in the system were adopted as the control indicators for determining the slag reaction. Using the proposed model, the reaction ratio of slag can be evaluated as a function of curing age, considering the influences of the water to binder ratio, the slag replacement ratio and the curing temperature. Furthermore, the amount of chemically-bound water (self-cementing properties), calcium hydroxide (pozzolanic capabilities), and the heat released from hydration are evaluated by determining the contributions from both the cement hydration and the slag reaction. The evaluated results show good accordance with the experimental results.     

Differential scanning calorimetry study of ordinary Portland cement paste containing metakaolin and theoretical approach of metakaolin activity

This paper aims to investigate the hydration and pozzolanic reactions in cement pastes with different levels of metakaolin replacement, using differential scanning calorimetry (DSC) and theoretical analysis based on reaction stoichiometry. It was found that the DSC technique could follow the hydration process quantitatively by measuring the peak temperature and enthalpy corresponding to decomposition of hydration products, as functions of age. The pozzolanic process can also be followed from the measurements of the changes in the amount and the nature of amorphous material in the paste and the change of the amount of calcium hydroxide. In addition, it was confirmed that a theoretical approach using reaction stoichiometry could give a good estimation of the concentration of calcium hydroxide in a metakaolin concrete.     

Use of calcium carbide residue and bagasse ash mixtures as a new cementitious material in concrete

Calcium carbide residue (CCR) is a by-product of the acetylene gas production and bagasse ash (BA) is a by-product obtained from the burning of bagasse for electricity generation in the sugar industry. The mixture between CCR contains a high proportion of calcium hydroxide, while BA is a pozzolanic material, can produce a pozzolanic reaction, resulting in the products similar to those obtained from the cement hydration process. Thus, it is possible to use a mixture of CCR and BA as a cementitious material to substitute for Portland cement in concrete. The results indicated that concrete made with CCR and BA mixtures and containing 90 kg/m³ of Portland cement gave the compressive strength of 32.7 MPa at 28 days. These results suggested that the use of ground CCR and ground BA mixtures as a binder could reduce Portland cement consumption by up to 70% compared to conventional concrete that requires 300 kg/m³ of Portland cement to achieve the same compressive strength. In addition, the mechanical properties of the alternative concrete including compressive strength, splitting tensile strength, and elastic modulus were similar to that of conventional concrete.     

Alkali activation of reactive silicas in cements: in situ 29Si MAS NMR studies of the kinetics of silicate polymerization

In the highly alkaline environment of the cement paste of a concrete, a source of silica can potentially react in two ways. In the pozzolanic reaction, it can combine with free lime to generate additional calcium silicate hydrate binding phase. Alternatively, reaction with alkali to form a gel can occur; this gel may swell and degrade the concrete. ²⁹Si magic angle spinning (MAS) and cross-polarization (CP) MAS nuclear magnetic resonance (NMR) studies have been performed to determine the silicate connectivity in some model cement systems; ²⁹Si enrichment was utilized to enable a series of spectra to be acquired in situ from a single sample.The hydrate from pozzolanic reaction of lime with silica was similar to the hydrate formed around silica in blended pozzolanic cements, with a relatively high crystallinity and long silicate chains. In the absence of lime, silica reacted with an alkaline solution to produce a gel having a high degree of cross linking, and a range of silicate mobilities. Tricalcium silicate hydration was found to be accelerated significantly by high levels of alkali (KOH) in solution; the hydrate formed had shorter silicate chains and was more crystalline than that produced by reaction in pure water. Hydration in alkali solution of a model blended cement, comprising a mixture of tricalcium silicate and silica, gave rise to two products, a long chain calcium silicate hydrate (C-S-H) and an alkali silicate of low rigidity. The alkali silicate phase gradually polymerized; at later ages it underwent a phase change, although no crystalline phase appeared to be formed. Silicate exchange took place between the C-S-H and the alkali silicate phase at a slow rate.     

Blended cements containing high volume of natural zeolites: Properties, hydration and paste microstructure

In this study, properties and hydration characteristics as well as paste microstructure of blended cements containing 55% by weight zeolitic tuff composed mainly of clinoptilolite mineral were investigated. Free Ca(OH)₂ content, crystalline hydration products and decomposition of zeolite crystal structure, pore size distribution and microstructural architecture of hydrated cement pastes were examined. Superplasticizer requirement and compressive strength development of blended cement mortars were also determined. The blended cements containing high volume of natural zeolites were characterized with the following properties; (i) no free Ca(OH)₂ in hardened pastes at the end of 28 days of hydration, (ii) less proportion of the pores larger than 50 nm when compared to portland cement paste, (iii) complete decomposition of crystal structure of zeolite at the end of 28 days of hydration, (iv) presence of tetra calcium aluminate hydrate as a crystalline product of pozzolanic reaction, (v) more compatibility with the melamine-based superplasticizer when compared to the naphthalene based product, and (vi) similar 28 days compressive strength of mortars to that of reference portland cement.     

Influence des fumées de silice sur l’évolution de l’hydratation des pâtes de chaux ou de Ciment Portland

The silica fume (SF) is used in civil engineering, in particular for the manufacture of high performance concrete.In order to better understand the gain in strength of the concretes containing SF, the microstructural aspect has been examined.Mixtures of SF–Lime pastes present a hydraulic setting which is due to the formation of a C–S–H phase (calcium silicate hydrate). The latter is semi-crystallized. It is characterized by the lines of X-ray diffraction, hk0 such as: 3,06 Å (220), 2,80 Å (400) and 1,83 Å (040).The mix design SF–Lime paste is thus a simplified approach of that of the mixtures SF–OPC in which the main reaction is the fixation, by the SF, of lime coming from the hydration of C₃S in the form of C–S–H.Tests have been carried out on two varieties of SF resulting from the same furnace with the presence of lime or Portland cement. The results show that the presence of certain impurities, by their actions on the solubility of silica plays a significant role on the evolution of the hydration of the principal components of Portland cements and the kinetics of lime fixation by the SF.Among the impurities contained in the SF, carbon delays considerably the hydration of the principal components of Portland cement (C₃S and C₃A) as well as the pozzolanic reactivity of the silica fume without removing it.     

Assessing the effect of biomass ashes with different finenesses on the compressive strength of blended cement paste

This study assesses the effect of biomass ashes with different finenesses on the compressive strength of blended cement paste. rice husk ash (RHA), palm oil fuel ash (POFA) and river sand (RS) were ground to obtain two finenesses: one was the same size as the cement, and the other was smaller than the cement. Type I Portland cement was replaced by RHA, POFA and RS at 0%, 10%, 20%, 30% and 40% by weight of binder. A water to binder ratio (W/B) of 0.35 was used for all blended cement paste mixes. The percentages of amorphous materials and the compressive strength of the pastes due to the hydration reaction, filler effect and pozzolanic reaction were investigated. The results showed that ground rice husk ash and ground palm oil fuel ash were composed of amorphous silica material. The compressive strength of the pastes due to the hydration reaction decreased with decreasing cement content. The compressive strength of the pastes due to the filler effect increased with increasing cement replacement. The compressive strengths of the pastes due to the pozzolanic reaction were nonlinear and were fit with nonlinear isotherms that increased with increasing fineness of RHA and POFA, cement replacement rate and age of the paste. In addition, the model that was proposed to predict the percentage compressive strength of the blended cement pastes on the basis of the age of the paste and the percentage replacement with biomass ash was in good agreement with the experimental results. The optimum replacement level of rice husk ash and palm oil fuel ash in pastes was 30% by weight of binder; this replacement percentage resulted in good compressive strengths.     

The utilization of thin film transistor liquid crystal display waste glass as a pozzolanic material

This investigation elucidates the pozzolanic behavior of waste glass blended cement (WGBC) paste used in thin film transistor liquid crystal displays (TFT-LCD). X-ray diffraction (XRD) results demonstrate that the TFT-LCD waste glass was entirely non-crystalline. The leaching concentrations of the clay and TFT-LCD waste glass all met the current regulatory thresholds of the Taiwan EPA. The pozzolanic strength activity indices of TFT-LCD waste glass at 28 days and 56 days were 89% and 92%, respectively. Accordingly, this material can be regarded as a good pozzolanic material. The amount of TFT-LCD waste glass that is mixed into WGBC pastes affects the strength of the pastes. The strength of the paste clearly declined as the amount of TFT-LCD waste glass increased. XRD patterns indicated that the major difference was the presence of hydrates of calcium silicate (CSH, 2 theta=32.1 degrees), aluminate and aluminosilicate, which was present in WGBC pastes. Portland cement may have increased the alkalinity of the solution and induced the decomposition of the glass phase network. WGBC pastes that contained 40% TFT-LCD waste glass have markedly lower gel/space ratios and exhibit less degree of hydration than ordinary Portland cement (OPC) pastes. The most satisfactory characteristics of the strength were observed when the mixing ratio of the TFT-LCD waste glass was 10%.     

Investigation on micronized biomass silica as a sustainable material

Micronized biomass silica (MBS) is an agricultural waste obtained from controlled burning of rice husk and grind in jar mill. This paper investigates the optimum percentage of MBS for the replacement of cement by conducting several experiments with the blended cement paste and mortar with MBS percentages varying from 0, 4, 8 and 12. In addition, hydration products were also investigated in the blended cement paste through X-ray diffraction. Due to the pozzolanic reaction of MBS with cement hydrates, secondary calcium silicate hydrates (CSH) were formed and also MBS which has a potential to reduce the intensity of Ca(OH)₂ exhibited improved properties. The experimental results showed that the optimum percentage of MBS for the replacement of cement was 8% for the materials used in this study. The mechanical and durability properties of recycled aggregate concrete by replacing cement with 8% MBS were also carried out and it was found that the concrete exhibited improved properties. There by, using MBS one can overcome the drawbacks of recycled aggregate concrete as it acts as a supplementary cementitious material. Thus, by combining recycled concrete aggregate with MBS will achieve sustainable development.     

Pozzolanic cements

Natural and artificial pozzolanas have been used to obtain hydraulic binders for over a thousand years. Hardening of pozzolanic cement pastes can result from the reaction between pozzolana and the lime that is added to the mix as hydrated lime or is produced following hydration of portland cement silicates. The pozzolanic reaction does not alter cement clinker hydration; it complements and integrates the hydration process because it results in a lower portlandite content and an increase in calcium silicate hydrates.

Besides reviewing the most recent investigations on pozzolana-containing cements, this paper shows that the behaviour of different types of pozzolana can be quite similar when they are blended and become hydrated along with portland cement clinker. Portland cement properties may undergo several qualitative modifications the extent of which substantially depends on the pozzolana/clinker ratio. So, a maximum is reached in pozzolanic cements.

As in the case of pozzolanic cements, for which the current pozzolana content is about one third by weight of cement, the most outstanding variations induced in the behaviour of portland cement can be summarised as follows. Heat of hydration decreases whilst the rate of clinker hydration increases, paste porosity increases and permeability decreases, both portlandite content and Ca/Si ratio in C-S-H decrease and the C-S-H content increases.

Chemical and physical properties of pozzolanic cements eventually affect engineering ones. Early strength of both pastes and concretes decreases while ultimate strength is often found to exceed that of the reference portland cement.

If cements contain small amounts of very active pozzolana (silica fume, for example), both early and ultimate strengths may be higher than those of the substituted cement.

Creep is found to increase definitely with increasing pozzolana content whereas shrinkage remains practically unaffected.

Chemical and microstructural variations in the paste also influence resistance of concretes to environmental attacks.

The low basicity and permeability resulting from the presence of pozzolana increase the concrete's resistance to lime leaching, sulphate and sea water attacks, and chloride penetration. Carbonation depth is practically unaffected. Pozzolana containing cements can help avoid expansion induced by alkali-silica reaction. Concrete resistance to freezing is not affected by the use of pozzolanic cement since it basically depends on the entrained air content.

The results of a variety of studies introducing a comparison between pozzolana-containing cements and corresponding portland cements can be summarised as follows: cements with appreciable pozzolana contents perform better in the long term rather than at an early age.

In most cases, however, the differences between the two types of cements are not so marked and as a consequence both cements are interchangeable especially for the most common building types.     

An investigation of the hydration chemistry of ternary blends containing cement kiln dust

During the manufacture of Portland cement, dust is generated composed of particles of feedstock and condensed volatilised inorganic salts. Due to its highly alkaline soluble fraction, the dust can be used as an activator in blends containing pozzolanic materials or hydraulic slags, allowing them to undergo cementitious reactions. The inclusion of Portland cement in such blends enhances strength development further, although careful proportioning of materials will be required to obtain optimum performance. Ternary systems containing cement kiln dust, pulverised-fuel ash and Portland cement were characterised in this paper in terms of strength development and hydration products. For a given Portland cement content, optimum strength was achieved in blends containing approximately 10% cement kiln dust for Portland cement levels up to 80%. Beyond this level a CKD/PFA ratio of one was optimal. Isothermal conduction calorimetry results and measurements of calcium hydroxide levels indicated that this was due to an acceleration of the reactions of the blend constituents by the dust. Additionally, the chemical composition of the optimal blends promoted the production of calcium aluminate and ferrite hydrates of a type conducive to maintaining the integrity of the cementitious matrix.     

Effect of nano clay particles on mechanical, thermal and physical behaviours of waste-glass cement mortars

Worldwide, around 2.6 billion tons of cement is produced annually. This huge size of production consumes large amounts of energy and is one of the largest contributors to carbon dioxide (CO₂) release. Accordingly, there is a pressing demand to minimise the quantity of cement used in the concrete industry. The main challenge to this is to get durable concrete with less cement and within reasonable cost. The economic, environmental and engineering benefits of reusing ground waste-glass powder (WGP) as a partial cement replacement has been established, but low glass reactivity and the possible alkali-silica reaction (ASR) are a drawback. Recent advances in nano-technology have revealed that nano-sized particles such as nano clay (NC) have a high surface area to volume ratio that provides the potential for tremendous chemical reactivity, accelerating pozzolanic activity and hindering ASR. This paper presents a laboratory study of the properties of NC/WGP cement composites. The microstructure, ASR, fracture energy, compressive and flexural properties of cement mortars containing WGP as a cement replacement with and without NC are investigated and compared with plain matrix. In addition, the hydration of cement compounds was followed by differential thermal analysis (DTA), thermogravimetric analysis (TGA), and also X-ray diffraction (XRD). The results showed that incorporation of glass powder has a positive effect on the mechanical properties of cement mortars after 28 days of hydration. Also, the results revealed that the mechanical properties of the cement mortars with a hybrid combination of glass powder and NC were all higher than those of plain mortar and with glass powder after 28 days of hydration. In addition, the DTA/TGA results and XRD analysis showed a reduction in the calcium hydroxide (CH) content in mortars with glass powder and with a hybrid combination of glass powder and NC, which confirms the improvements of mechanical properties and occurrence of pozzolanic reaction after 28 days of hydration.     

Properties of high volume glass powder concrete

Mechanical and durability properties of concrete with cement replaced by finely grounded glass powder in high volume up to 60% were investigated. XRD and TGA analyses indicated that the fine glass powder reacted with calcium hydroxide to form calcium-silicate-hydrates. As such, the microstructures of concrete were more compact and homogeneous, especially at the interfacial transition zone. Concrete with cement replaced by 15% and 30% glass powder exhibited the highest strength increase and correspondingly the lowest porosity. Beyond a replacement of 30%, calcium hydroxide became insufficient for the pozzolanic reaction of glass powder. However, the high volume glass powder concrete retained distinct resistance against water and chloride ingress, due to the reduction in pore size and connectively. Reductions of 77%, 83%, 96%, 91% and 92% were observed respectively for water penetration depth, sorptivity, conductivity, chloride diffusion and migration coefficients in concrete with cement replaced by glass powder by 60%.     

β-Belite cements (β-dicalcium silicate) obtained from calcined lime sludge and silica fume

The utilization of lime sludge (LS), a pulp and paper industry residue, and silica fume (SF), a ferrosilicon industry by-product, as raw materials for the preparation of β-dicalcium silicate (β-C₂S or β-belite) is investigated. β-phase belite is synthesized in a molar ratio of calcined LS/SF at 2.0 by hydrothermal method followed by calcination at 1000 °C for 2 h, which is lower temperature than conventional production temperature of about 1200 °C, and importantly without any chemical stabilizers. The produced belite cements containing 89.3% of β-belite, the rest being α-belite (5.93%), tobermorite (C–S–H, 1.71%), cristobolite (SiO₂, 1.83%) and free lime (CaO, 1.24%). The micro analytical characteristic of the raw materials and formed belite are examined by means of TG-DTA-DTG, XRF, XRD, SEM with EDAX, FT-IR, BET techniques and isothermal conduction calorimetry. The hydration of pastes and compressive strength of mortars of the formed β-belite blended with ordinary Portland cement are studied with a partial replacement of cement by 10%, 20% and 30%. The reaction of β-belite in combination with Portland cement is comparable up to 10% replacement of cement to the pozzolanic reactions of other materials used in similar ways. However, it is observed that the premature stiffening of belite incorporated cement pastes takes place with low heat of hydration because of higher reactivity of belite cement incorporation.     

Investigating the role of reactive silica in the hydration mechanisms of high-calcium fly ash/cement systems

High-calcium fly ashes (ASTM Class C) are being widely used as a replacement of cement in normal and high strength concrete. In Greece such fly ashes represent the majority of the industrial by-products that possess pozzolanic properties. Even thought the contribution of factors, such as fineness and water/binder ratio, on the performance of fly ash/cement (FC) systems has been a common research topic, little work has been done on examining whether and to what extent reactive silica of fly ashes affects the mechanisms occurring during their hydration.The work presented herein describes a laboratory scale study on the influence of active silica of two high-lime fly ashes on their behavior during hydration. Volumes up to 30% of Greek high-calcium fly ashes, diversified both on their reactive silica content and silicon/calcium oxides ratio, were used to prepare mixes with Portland cement. The new blends were examined in terms of compressive strength, remaining calcium hydroxide, generation of hydration products and microstructural development. It was found that soluble silica of fly ashes holds a predominant role especially after the first month of the hardening process. At this stage, silica is increasingly dissolved in the matrix forming additional cementitious compounds with binding properties, principally a second generation C–S–H. The rate however, that fly ashes react in FC systems seems to be independent of their active silica content, indicating that additional factors such as glass content and fineness should be taken into account for predicting the contribution of fly ashes in the final performance of pozzolanic cementitious systems.     

Particle size effect on the strength of rice husk ash blended gap-graded Portland cement concrete

Rice husk ash (RHA) has been used as a highly reactive pozzolanic material to improve the microstructure of the interfacial transition zone (ITZ) between the cement paste and the aggregate in high-performance concrete. Mechanical experiments of RHA blended Portland cement concretes revealed that in addition to the pozzolanic reactivity of RHA (chemical aspect), the particle grading (physical aspect) of cement and RHA mixtures also exerted significant influences on the blending efficiency. The relative strength increase (relative to the concrete made with plain cement, expressed in %) is higher for coarser cement. The gap-grading phenomenon is expected to be the underlying mechanism. This issue is also approached by computer simulation. A stereological spacing parameter (i.e., mean free spacing between mixture particles) is associated with the global strength of the blended model cement concretes. This paper presents results of a combined mechanical and computer simulation study on the effects of particle size ranges involved in RHA-blended Portland cement on compressive strength of gap-graded concrete in the high strength/high performance range. The simulation results demonstrate that the favourable results for coarser cement (i.e., the gap-graded binder) reflect improved particle packing structure accompanied by a decrease in porosity and particularly in particle spacing.     

Simulation of silica fume blended cement hydration

A model is proposed in this paper to simulate silica fume (SF) blended cement hydration based on the kinetics, stoichiometry and physical chemistry of cement hydration and pozzolanic reaction. The pozzolanic reaction degree, volume fraction of hydration products, capillary porosity and gel porosity can be obtained from model simulation. By using proper amount of silica fume replacement, the microstructure of silica fume blended cement paste is improved since the volume fraction of C-S-H gel is increased, Ca(OH)₂ content and capillary porosity are decreased due to pozzolanic reaction compared with ordinary Portland cement (OPC) paste. The effects of silica fume particle size, glass phase content and the percentage of silica fume replacement on pozzolanic reaction degree, volume fraction of hydration products, and capillary porosity are simulated. The simulation results show that finer silica fume particles with higher glass phase content (GP) are of higher reactivity. There is an optimum silica fume replacement; extra silica fume only acts as inert filler because there is no enough Ca(OH)₂ from cement hydration to react with it pozzolanically.

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Résumé Le modèle proposé dans cet article simule l'hydratation de ciment mélangé à de la fumée de silice et est basé sur la cinétique, la stoichiométrie et la physico-chimie de l'hydratation du ciment et la réaction pozzolanique. Le degré de réaction pozzolanique, la fraction volumique des produits de l'hydratation, la porosité capillaire et la porosité de gel peuvent être obtenues par un modèle de simulation. En utilisant la bonne quantité de remplacement de fumée de silice, la microstructure de la fumée de silice mélangée à la pate de ciment est améliorée étant donné que la fraction volumique du gel C-S-H augmente, que le taux de Ca(OH)₂ et la porosité capillaire décroissent en raison de la réaction pozzolanique lorsque l'on compare avec une pate de ciment à base de Portland ordinaire (OPC). Les effets de la taille des particules de fumée de silice, le contenu de la phase de verre et le pourcentage de remplacement de fumée de silice sur le degré de réaction pozzolanique, la fraction volumique des produits d'hydratation et la porosité capillaire sont simulés. Les résultats de cette simulation montrent que de plus fines particules de fumée de silice avec une plus grande quantité de phase de verre (GP) sont de forte réactivité. Il existe un remplacement de fumée de silice optimal; de la fumée de silice en plus ne sert que de filler inerte car il n'y a pas assez de Ca(OH)₂ à partir de l'hydratation du ciment pour provoquer une réaction pozzolanique

     

Strength development of ternary blended cement with limestone filler and blast-furnace slag

The benefits of limestone filler (LF) and granulated blast-furnace slag (BFS) as partial replacement of portland cement are well established. However, both supplementary materials have certain shortfalls. LF addition to portland cement causes an increase of hydration at early ages inducing a high early strength, but it can reduce the later strength due to the dilution effect. On the other hand, BFS contributes to hydration after seven days improving the strength at medium and later ages.Mortar prisms in which portland cement was replaced by up to 20% LF and 35% BFS were tested at 1, 3, 7, 28 and 90 days. Results show that the contribution of LF to hydration degree of portland cement at 1 and 3 days increases the early strength of blended cements containing about 5–15% LF and 0–20% BFS. The later hydration of BFS is very effective in producing ternary blended cements with similar or higher compressive strength than portland cement at 28 and 90 days. Additionally, a statistical analysis is presented for the optimal strength estimation considering different proportions of LF and BFS at a given age. The use of ternary blended cements (PC–LF–BFS) provides economic and environmental advantages by reducing portland cement production and CO₂ emission, whilst also improving the early and the later compressive strength.