Natural Pozzolan Research Articles

Decarbonization of the concrete railway sleeper production: bringing the low-dosage pozzolanic cement usage in the sleeper production via novel laminated CFRPU reinforcement technique

This study presents four new concrete railway sleeper models' environmental emission and service life investigations. Both of these two factors are crucial for a sustainable railway sleeper model. Investigated sleepers are solely reinforced with engineered laminated carbon-fiber-reinforced polyurethane (L-CFRPU) materials. This novel concrete sleeper reinforcement technique was needed to overcome the following two challenges preferred because of the environmental sustainability objectives: First, the new LCR-G-type sleepers are produced with a 30% lower (on average) cement dosage. Second, an eco-friendly cement containing approximately 50% natural pozzolan is utilized. Accordingly, the new sleeper model's total concrete raw materials-based equivalent CO2 emission value is 54% less (on average) than conventional concrete railway sleepers. This emission decrease (decarbonization) rate is well above the other eco-friendly concrete sleeper studies in the literature. However, the compressive strength of the sleeper concrete has almost halved. For this reason, investigations continued with the mechanical strength tests specified in the concrete sleeper standards for preliminary service life evaluations. For these purposes, in this study, the latest EN 13230-3:2016 standard test setup was used with some improvements, such as precise deflection measurements oriented to the sleeper-rail-seat- center points. The test results show that all four models of new LCR-G-type sleeper variations have met the sleeper technical specifications' static strength limits and crack-reclosing conditions. Consequently, it is recommended to investigate further the sustainability potential of this new concrete sleeper production method, whose preliminary evaluations have been made in this study for the first time in the literature.

Utilization of waste glass with natural pozzolan in the production of self-glazed glass-ceramic materials

Abstract Significant self-glazed glass-ceramic was obtained from a natural pozzolan and external glass cullet. Natural pozzolan with/without glass cullet was fused to glass melt that quenched in water to glass frits. The dried glass frits were pulverized (<0.083 mm) and then shaped in a stainless mold. The thermal behavior of the glasses shows a widening of the crystallization temperature with the incorporation of the glass cullet between ∼800 and 950°C. Sintering of the shaped glass powder at 1,050°C/2 h lead to the crystallization of augite, enstatite, cristobalite, and hematite. The microcrystalline structure shows massive texture with pores in-between; however, at high magnification regular euhedral to subhedral crystals in submicron to nearly submicron size was developed in the glassy matrix and their microanalysis indicates the dominant augite. The density of the glass-ceramic samples decreases from 2,706 to 2,539 kg/m3 with the incorporation of glass wastes. The sample surfaces show, through force electron microscopy, the fineness and smoothness of the grains with the incorporation of the glassy portion. The microhardness values were between 6.43 and 6.11 GPa. The coefficient of thermal expansion increased from 32.87 (25–300°C) to 66.89 (25–500°C) × 10−7°C−1. The chemical resistance of samples in water (0.0002–0.0016) is better than in an acidic medium (0.0011–0.0017). These glass-ceramic enjoy good density, hardness, and thermal expansion and can be used in the ceramic industry and cladding walls and floors.

Early hydration studies of cementitious materials incorporating nanoalumina

Concrete technologists use different types of additives such as fly ash, slag, natural pozzolans and nanomaterials toenhance concrete performance and durability. However, a detailed explanation of the early-age hydration process and microstructural modification of concrete in the presence of nanomaterials remains to be presented and extensive research is required for strategic modification of cementitious systems. This study focused on the precise monitoring of early-age hydration with the incorporation of nanoalumina (nAl) in tricalcium silicate (C3S) and Portland cement paste and mortar. The dosage of nAl was varied from 1 to 5% (by weight) in C3S and from 0.1 to 1.0% in Portland cement, with a water/cement ratio of 0.4. The hydration studies showed that the nAl increased the cross-linkage in calcium silicate hydrate gel through substitution of aluminium by silicon, which was responsible for the enhancement of the modulus of elasticity (by 40%) with 1.0% nAl) after 7 days of hydration. In summary, the incorporation of nAl modified the concrete microstructure in the initial days of hydration, leading to higher concrete performance and longer service lives of concrete structures.

Novel application of Chilean natural pozzolan for sustainable strain-hardening cementitious composite

This study aims to develop a novel solution to improve the sustainability and resiliency of the infrastructure in Chile. Due to the country's unique geographic situation of the coastal environment and high seismicity, the key is to design a low-carbon strain-hardening cementitious composite (SHCC) by replacing ordinary portland cement (OPC) with an abundant Chilean natural pozzolan (NP). The results indicate that the optimal replacement level is 30%. The newly developed NP-based SHCC shows a tensile strength of 6 MPa, a tensile strain capacity of 2.5%, and micro-cracks of <100 µm. In addition, this study also quantifies the environmental impact of the NP-based SHCC using a ‘cradle-to-gate’ life-cycle analysis. By replacing OPC with the NP, the CO2 emission of NP-based SHCC reduces by 23%. The excellent tensile properties and cracking control suggest that NP-based SHCC could contribute to developing sustainable and resilient Chilean infrastructure.

Mechanical properties of eco-friendly cement based composite mortars plastic fiber reinforced partially replaced by natural pozzolan and marble waste

This research presents a study on the mechanical properties of mortar specimens reinforced with plastic fibers incorporating natural Moroccan pozzolan and marble waste as partial substitutes for cement. Cement is a widely used material, but its production contributes significantly to CO2 emissions. And reducing the carbon footprint of materials without increasing costs is a critical challenge. Hence, numerous studies have investigated the partial or complete substitution of cement. Moroccan pozzolan, a natural pozzolanic material, offers an alternative to energy-intensive cement production. Marble waste, an industrial byproduct generated during the sawing, shaping, and polishing of marble, poses a significant environmental threat. Likewise, the issue of environmental pollution caused by plastic has received lot of attention, and the ideal solution recommended is recycling. In this sense, twenty-one mixes were synthesized and evaluated to explore the mechanical properties of the fiber-reinforced mortars based on natural pozzolan and marble waste added at different weight percentages (5–5/10–5/5–10/15–0/0–15/7.5–7.5) as a partial replacement for cement and 1% and 2% plastic fibers, based on the mortar volume. The hardened mortar mixtures were tested for compressive strength determined after 7 and 28 days, and flexural strength by a three point bending machine. The test results revealed that the mortar specimens containing marble waste and natural pozzolan exhibited the highest compressive strength. The addition of plastic fibers positively influenced the compressive and flexural strength of the mortars. Optimal percentages of natural pozzolan, marble waste, and plastic fibers were identified. The best-performing mixture achieved a compressive strength of 18.67 MPa with 5% pozzolan, 5% marble waste, and 2% plastic fibers added to the mortar mix. This approach not only addresses the uncontrolled disposal of plastic and marble waste but also provides an opportunity to utilize abandoned natural resources, creating more durable and environmentally friendly composite mortars.

Production of autoclaved lightweight concretes using pottery stone and bagasse ash

This study investigated the influence of pottery stone and bagasse ash on the mechanical features of autoclaved lightweight concrete. Pottery stone is a natural resource of igneous rock weathering commonly exists with white clay, feldspar and limestone. This raw material is mainly composed of quartz and mica that has been used for the production of ceramic products. Bagasse ash is a waste product of the sugar refining process that causes serious environmental pollution. Pottery stone and bagasse ash waste were physically characterized and partially substituted by the weight of cement in lightweight concrete with the addition of aluminium powder at a certain amount. The use of aluminium powder showed a positive effect on the porosity of lightweight bodies. Compressive strength, density and thermal conductivity were determined. Pottery stone can be used as a natural pozzolan for the production of lightweight concrete. Lightweight concrete manufactured with 17.5% pottery stone and 17.5% bagasse ash showed low density and good compressive strength. Autoclaved lightweight concrete is considered an economy in the consumption of pottery stone and bagasse ash waste as cement replacement, therefore enhancing the possibility of its reuse in a sustainable way.

Efflorescence Formation Mechanism and Control for Geopolymer Paste Specimens Made from Natural Pozzolan and Calcium Hydroxide Binders

Efflorescence Formation Mechanism and Control for Geopolymer Paste Specimens Made from Natural Pozzolan and Calcium Hydroxide Binders

Towards performance-based specifications for fly ash and natural pozzolans – Insights from a Monte-Carlo based thermodynamic modeling framework

Monte-Carlo-based thermodynamic modeling framework is used to assess the chemical limits set by ASTM C618-23. Realistic chemistries and reactivities for supplementary cementitious materials (SCMs) and chemistries for cement are generated using statistical data from the literature. 200,000 thermodynamic simulations are performed for each cement+SCM system to evaluate performance through Ca(OH)2 content, capillary porosity, and C-S-H volume. The results indicate that the reactivity of SCMs is directly related to its performance in paste, and its inclusion in ASTM C618 would be beneficial for optimized utilization of SCMs in performance-based mixtures. When providing chemical limits for SCMs, separating the reactive pozzolanic oxides (RPO) from bulk oxide composition is critical for paste performance. Fe2O3 content did not significantly impact the performance. If RPO is specified, fly ashes and natural pozzolans could have similar chemical limits. SCMs can be classified based on CaO and SO3 contents to affect Ca(OH)2 and AFt in paste, respectively.

Sustainable cementitious materials: exploring alkali-activated binders with natural pozzolan

The present paper describes the potential use of NP from Algeria for the production of a new AAB. CEMII 42.5 cement is added to the NP as calcium resource. The mixtures are then activated by NaOH, Na2SO4 and Na2SiO3 at concentrations of 3, 7 and 11%. The chemical activators are both added in liquid and/or solid form to develop a one-part alkali-activated material. XRD, ATG/ATD and SEM/EDS are used to assess microstructure and elemental composition of the hydration products. Fresh properties, such as, consistency and setting time of various mixtures and compressive strengths of AABs specimens cured for 7, 28, 90 and 420 days are determined. The cement carbon footprint vs strength ratio (kg·CO2·eq/MPa) is suggested as an indicator to highlight the environmental contribution of the AABs. The results indicate that AABs show different strength levels depending on the activator type and its concentration. Maximum 28-day compressive strength of 25.2 MPa is achieved with 7 % Na2SiO3. A high early strength development is also noted since more than 50% of the strength could be achieved within 7 days. Finally, the environmental advantage is demonstrated as the global warning of the AABs can be 70% lower than that of OPC.

Experimental Research on Natural Pozzolan as Cement Replacement

This paper presents the properties of mortar and concrete with NBRRI pozzolan as partial replacement of cement. In this research, NBRRI pozzolan from NBRRI and local cement (Dangote) are used. Firstly, chemical composition of NBRRI pozzolan and Dangote cement are analyzed. And then the physical properties of local materials used in this research are determined according to ASTM procedure. Partial replacement percentages of pozzolan are considered 10%, 20%, 30% and 40%. The strength of mortar and concrete with NBRRI pozzolan (0%, 10%, 20%, 30%, and 40%) is tested at 7 days, 14 days and 28 days. From the trial mix design, the water-cement ratio (0.555) is obtained by using the least square method. To get target strength (4000 psi), by using water-cement ratio (0.555) and 68% of maximum aggregate size (20 mm), the concrete mix proportion (1:1.9:3) is obtained. The compressive strength of concrete with various percentages of NBRRI pozzolan at 21 days and 28 days are more than 7 days and 14 days strength. Therefore, it can be concluded that NBRRI pozzolan can be used as cement replacement material when high strength performance in structures is not required.

Future and emerging supplementary cementitious materials

To sustain the decarbonization of the cement industry, identifying new sources of supplementary cementitious materials (SCMs) is crucial. This review paper examines recent scientific literature on the understanding, assessment, and processing of future and emerging SCM resources. Among the SCMs that have generated significant interest are calcined clays, natural pozzolans, reclaimed coal fly ashes, certain biomass ashes, concrete recycling fines, and recycled glass. These SCMs are gaining market access, and their processing and performance have been well-established in local contexts.A growing body of research is considering a much wider array of by-product and waste materials as potential future SCM sources. These materials are often available in high volumes, but they typically require beneficiation processing to enhance their performance and compatibility as SCM. While promising results have been achieved for many materials, future research and development efforts are necessary to better understand their impact on cement and concrete properties and establish or improve the viability of the proposed beneficiation processing.In conclusion, this review highlights the latest developments in testing and specifications that support the uptake of a wider range of SCMs in cement and concrete.

Diatomites from the Iberian Peninsula as Pozzolans.

The object of this work is to study and characterize diatomites from the southeast of the Iberian Peninsula to establish their character and quality as natural pozzolans. This research carried out a morphological and chemical characterization study of the samples using SEM and XRF. Subsequently, the physical properties of the samples were determined, including thermic treatment, Blaine particle finesse, real density and apparent density, porosity, volume stability, and the initial and final setting times. Finally, a detailed study was conducted to establish the technical properties of the samples through chemical analysis of technological quality, chemical analysis of pozzolanicity, mechanical compressive strength tests at 7, 28, and 90 days, and a non-destructive ultrasonic pulse test. The results using SEM and XRF show that the samples are composed entirely of colonies of diatoms whose bodies are formed by silica between 83.8 and 89.99% and CaO between 5.2 and 5.8%. Likewise, this indicates a remarkable reactivity of the SiO2 present in both natural diatomite (~99.4%) and calcined diatomite (~99.2%), respectively. Sulfates and chlorides are absent, while the insoluble residue portion for natural diatomite is 1.54% and 1.92% for calcined diatomite, values comparatively lower than the standardized 3%. On the other hand, the results of the chemical analysis of pozzolanicity show that the samples studied behave efficiently as natural pozzolans, both in a natural and calcined state. The mechanical tests establish that the mechanical strength of the mixed Portland cement and natural diatomite specimens (52.5 MPa) with 10% PC substitution exceeds the reference specimen (51.9 MPa) after 28 days of curing. In the case of the specimens made with Portland cement and calcined diatomite (10%), the compressive strength values increase even more and exceed the reference specimen at both 28 days (54 MPa) and 90 days (64.5 MPa) of curing. The results obtained in this research confirm that the diatomites studied are pozzolanic, which is of vital importance because they could be used to improve cements, mortars, and concrete, which translates to a positive advantage in the care of the environment.

Effect of inclusion of natural pozzolan and silica fume in cement - based mortars on the compressive strength utilizing artificial neural networks and support vector machine

This study illustrates the effect of incorporating natural pozzolan (NP) and silica fume (SF) in cement-based mortars on the compressive strength. Up to 40% of the weight of cement in cement mortars can be replaced by NP powder. NP in its natural state can be used to replace up to 40% of the volume of sand in cement mortars. The replacement levels of cement by weight with SF are 5% and 10% to improve the mechanical properties of the NP-based cement mortars. Experiments were conducted to assess the compressive strength of cement mortars containing NP at 28 and 180 days of curing. The water/cement ratio was 0.49 for all the specimens. Models for the compressive strength of NP-based cement mortars and NP-SF-based cement mortars were formulated based on nonlinear regression analysis, artificial neural network (ANN) , and support vector machine (SVM) approach to explore the impact and exchanges of cement, NP, and SF mixtures. The RMSE of the nonlinear, ANN, and SVM models revealed that the RMSE of the ANN is significantly less than that of the nonlinear and SVM models. A sensitivity analysis for the predicted compressive strength of NP-based cement mortars and NP-SF-based cement mortars was conducted. The application of the SVM technique was evaluated through four different kernels, including sigmoid, linear, polynomial, and radial basis function (RBF). The RBF kernel shows better performance and offers more accurate results than the sigmoid, linear, and polynomial kernels. The results showed that the NP replacing cement and the SF replacing cement are the most dominant parameters for the prediction of compressive strength. Finally, the developed models from this study can be used to predict the compressive strength of cement mortars containing NP and SF.

Mix design method of granular packing for high performance concrete with natural pozzolans

This study presents an enhanced mix design method for High performance concrete (HPC) with Natural Pozzolans (NP) content that considers material packing theory. Seven HPC mixes with different NP replacement levels of 0, 5, 10, 15, 20, 25, 30% by volume were conducted to investigate the effect of NP on the rheological and mechanical properties of HPC. A basic water demand experiment was designed to obtain the granular packing and packing density of mortar. Furthermore, the equivalent packing density was defined and calibrated to represent the effect of NP, And the bilinear interpolation method was used to analyses the HPC properties. The results show that the relative accuracies of the improved method are higher than 15% to the initial method. The HPC mixtures with NP was also assessed and shown to be within the optimum area.

Mechanical, environmental, and economic assessment of sustainable cement mortar using Afghan natural pozzolan as a partial replacement for cement

Using natural pozzolan to produce cement-based mortar is one of the suitable solutions to reduce cost, energy consumption, and environmental impacts. In this experimental study, the paste replacement methodology (replacement of partial cement wt% with supplementary cementitious material) is used. Natural pozzolan, as vernacular material with high silicate aluminate originating in Afghanistan, is replaced (6, 13, and 20%) with cement in mortar. Various tests such as slump, compressive strength, tensile strength, water absorption, freezing-thawing cycles, relative length change, pull-off test, and microstructure analysis have been performed to study the properties of fresh and hardened mortar. The findings showed that the use of natural pozzolan containing a high level of silicate and aluminate as a replacement of cement in mortar improved 56 days compressive and tensile strength of mortar by 2.2 and 6%, respectively, water absorption was reduced by 1.6%, and the resistance to the freezing and thawing cycles was increased 10.7% as well compared to the reference samples. In addition, the results of economic analysis and sustainable development indicators assessment of mortar showed that using this replacement methodology was economically acceptable and reduced the potential of global warming and energy consumption by 13% of the production of one ton of cement using standard technology. The optimum replacement percentage was selected at 13% without compromising the mechanical properties of mortar.

Impact of Natural Pozzolan and the Degree of Circularity of Aggregates on the Thickness, Strength and Durability of ITZ in Concrete (Modeling and Experimentation)

The interfacial transition zone (ITZ) has a significant negative impact on the structural performance of concrete. This negative impact can be ameliorated by introducing mineral additions into the concrete. In this study, different forms (degree of circularity) of coarse aggregates and three contents (10 %, 15 % and 20 %) of mineral addition (natural pozzolan) were used to prepare ordinary concrete. This article aims to determine the optimal and effective mixture (the best form of aggregate and addition). This article aims to determine the optimal and efficient mixture (the best form of aggregate and addition) on the basis of mechanical (compressive strength), and chemical (immersion in 3.5 % H2SO4 solution) tests. Furthermore, the effect of the interaction between the aggregate and the modified cementitious matrix was analyzed and discussed using the scanning electron microscope (SEM). The results show that the effect of the addition of 20 % pozzolana improves the aggregate/matrix transition zone, which made it possible to develop a maximum compressive strength at 60 days (51 MPa). In addition, the effect of mineral additions varies depending on the shape of the coarse aggregate. Thus, an effective numerical modeling of the compressive strength is based on the approach of the full factorial design taking into account the degree of circularity of the coarse aggregates and the content of the pozzolan.

Calcined Clays from Nigeria-Properties and Performance of Supplementary Cementitious Materials Suitable for Producing Level 1 Concrete.

In this work, four naturally occurring (two kaolinite-rich and two smectite-rich) clay samples were collected from different areas around the Ashaka cement production plant, located in Gombe State, Nigeria and calcined in a laboratory. The mineralogical characterization of the clays was carried out by XRD. The hydration kinetics of the calcined clay-cement systems were monitored by isothermal calorimetry. Workability was determined using the flow table method. The reactivity of the calcined clays was determined from the solubility of Si and Al ions and the strength activity index. All calcined clays studied met the requirements of ASTM C618 for the use of natural pozzolans as a partial replacement for hydraulic cement. The metasmectite clays yielded a higher specific surface area, increased water demand, and less reactive Si and Al ions compared to the metakaolin clays. The two calcined clay groups require the addition of superplasticizer to achieve a workability class similar to the Portland cement mortar system. They can be used to replace Portland cement at replacement levels of up to 45%, in combination with limestone powder to form an LC3 cement, thereby achieving at least a "Level 1" reduction in greenhouse gas emissions.

A Comprehensive Study on Non-Proprietary Ultra-High-Performance Concrete Containing Supplementary Cementitious Materials

Ultra-high performance concrete (UHPC) is a novel cement-based material with exceptional mechanical and durability properties. Silica fume, the primary supplementary cementitious material (SCM) in UHPC, is expensive in North America, so it is often substituted with inexpensive class F fly ash. However, future availability of fly ash is uncertain as the energy industry moves toward renewable energy, which creates an urgent need to find cost-effective and environmentally friendly alternatives to fly ash. This study investigated replacing cement, fly ash, and silica fume in UHPC mixtures with ground granulated blast-furnace slag (GGBFS), metakaolin, and a natural pozzolan (pumicite). To identify acceptable UHPC mixtures (28-day compressive strength greater than 120 MPa), workability, compression, and flexural tests were conducted on all mixtures. Then, durability properties including shrinkage, frost resistance, and chloride ion permeability (rapid chloride permeability and surface resistivity tests) were evaluated for the acceptable UHPC mixtures. Results showed that 75, 100, and 40% of fly ash in the control mixture could be replaced with pumicite, metakaolin, and GGBFS, respectively, while still producing acceptable strengths. Flexural strengths were greater than 14.20 MPa for all mixtures. For durability, UHPC mixtures had shrinkage strains no greater than 406 μstrain, durability factors of at least 105, and "very low" susceptibility to chloride ion penetration, indicating that these SCMs are suitable candidates to completely replace fly ash and partially replace silica fume in non-proprietary UHPC.

Optimization of alkali-activated binders using natural minerals and industrial waste materials as precursor materials

This paper presents the results of a study on developing optimized alkali-activated binders (AABs) utilizing selected natural minerals and industrial byproducts as precursor materials in addition to sodium hydroxide and sodium silicate as activators. Four selected precursor materials (natural pozzolana, limestone powder, red mud, and silicomanganese fume) were characterized in terms of their physical and chemical properties. The proportioning of the four precursor materials was optimized based on the results of flow, setting time, and compressive strength tests conducted on trial mortars. After reaching an optimal proportioning of the four precursor materials, the natural pozzolan was partially replaced by ordinary Portland cement (maximum 30% by wt.) to significantly enhance the properties of the AABs. The activator to precursor (A/P) ratio, sodium silicate to sodium hydroxide (NS/NH) ratio, sodium hydroxide (NH) molarity, and water to precursor (W/P) ratio, were varied from 0.3 to 0.6, 1 to 2.5, 8 to14 M, and 0.35 to 0.55, respectively. The influence of these activation parameters (at the optimally selected proportioning of precursor materials) on the physical and mechanical properties of AABs besides their mineral composition and morphology was investigated leading towards selecting the optimum AABs. The compressive strength at 28 days ranged from 28.5 to 32 MPa, 24.15 to 31.8 MPa, 24.2 to 33.1 MPa, 15.33 to 31.16 MPa, and 19.7 to 34.1 MPa, as A/P ratio, NS/NH ratio, NH molarity, W/P ratio, and curing method and duration were varied, respectively. XRD, FTIR, and SEM analyses of the AABs were conducted to validate the trends observed in the compressive strength results with variation in the activation parameters. The main phases detected by XRD included CSH, CASH, Mn-SH, KASH, and NASH. FTIR analysis showed bands that coincide with reported vibration and stretching of Si–O-M (M → Al, Si, or Mn) that are associated with geopolymerization, while SEM imaging showed dense microstructure with a homogenous distribution of polymerization gels that filled the microcracks and voids. Additionally, the effect of curing regimes (oven, steam and ambient-air curing) on the performance of AABs was also examined. The results of the present work enabled to identify the optimum proportioning of the selected precursor materials, optimum combination of A/P ratio, NS/NH ratio, NH molarity, and W/P ratio for producing the AABs with enhanced performance.

Valorification of Egyptian volcanic tuff as eco-sustainable blended cementitious materials

Rhyolite rocks extend from southern Egypt to northern Egypt in the Eastern Desert, and no effective economic exploitation of them has been discovered so far. The pozzolanic activities of different volcanic tuffs (VT) supplied from the Eastern Desert located in Egypt have been investigated as natural volcanic pozzolan materials to develop new green cementitious materials for achieving sustainability goals in the construction field. Experimentally in this paper, the pozzolanic activities of seven diverse specimens of Egyptian tuffs taken with standardized proportions of 75:25% (Cement: volcanic tuffs) were investigated. Pozzolanic features of such tuffs are examined comparatively via strength activity index (SAI), TGA, DTA, and the Frattini’s test. Chemical composition, petrographic, and XRD analysis were also performed for tuffs samples. The pozzolanic reaction degrees were determined according to the compressive strengths at 7, 28, 60 and 90 days with different replacement ratios (20, 25, 30 and 40%) of tuffs samples. Additionally, the micro-filler effects in mortar and concrete were determined by measuring the heat of hydration in mortar samples and the compressive strength of concrete with different additive ratios for tuffs samples besides, the concrete slump test. The results show that TF6 gives a lower cement heat of hydration value which is less than 270 J/g at 7 days. Also, its performance in concrete is better than silica fume at late strength (28 days) since the concrete index value is 106.2% by compared to the concrete index of silica fume 103.9 and therefore it can be used as an alternative to high price and quality variable silica fume (SF) for producing high-performance green concrete. Due to the good pozzolanic behavior proved by nearly most volcanic tuffs, along with their low cost, this study will be profitable for very auspicious the use of Egyptian volcanic tuffs for developing sustainable and eco‑friendly blended cement.