Alkali-activated Mortars Research Articles

Investigating the impact of foundry by-product sand as an activator on workability improvement and strength development in alkali-activated blast furnace slag mortar

The substitution of alkali-activated furnace slag significantly reduces the necessity of cement manufacture and mitigates the continuous growth of carbon emissions. In addition, it shows superior mechanical properties compared to traditional concrete materials. However, rapid setting issues hinder its widespread applications. This study investigated the innovative use of zero-carbon waste sodium silicate-bonded sand as a substitute for the fine aggregate and sodium silicate in traditional alkali-activated blast furnace slag mortar. The primary objective is to analyze the impact of waste sodium silicate-bonded sand on the workability and mechanical properties of the mortar. The key properties such as flowability, setting time, temperature measurement, compressive strength, and microstructural were analyzed to determine the improvement in workability and the strength development of alkali-activated blast furnace slag mortar resulting from the use of waste sodium silicate-bonded sand. The research showed the integration of waste sodium silicate-bonded sand results in an eco-friendly and cost-effective material, which addresses limitations in traditional activated blast furnace slag mortars. The finding revealed that substituting fine aggregate and sodium silicate with waste sodium silicate-bonded sand significantly improved the mechanical and workability properties of alkali-activated mortars. Notably, the compressive strength of mortars incorporating waste sodium silicate-bonded sand exceeded that of traditional Portland cement and effectively mitigated rapid setting issues. In addition, this approach led to an environmentally friendly mortar with satisfactory workability. The research emphasizes the practical benefits of utilizing waste sodium silicate-bonded sand and offers new insights into its effects on mortar performance. This has provided more details for future exploration and refinement in the field of alkali-activated materials.

Effect of organic corrosion inhibitors on the behaviour of repair mortars and reinforcement corrosion

Repairing concrete structures affected by reinforcement corrosion is vital to ensure their durability and safety. Organic corrosion inhibitors (OCIs) are widely used in the construction industry to prevent steel corrosion due to their effectiveness, sustainability, and health and safety benefits. However, the effects of these OCIs on different types of repair mortars have not been extensively studied. This study evaluated the fresh and hardened properties, as well as the corrosion resistance, of four types of repair mortars (polymer-modified, general cementitious, fine-grained, and alkali-activated) incorporated with two types of OCIs (amino alcohols and sodium gluconate-based) at dosages of 0.5 %, 1 %, and 2 %. Additionally, the corrosion kinetics of mortars under the influence of OCIs were analysed using the impressed current technique. The results indicated that OCIs generally enhanced workability and increased void content across all repair mortars. The amino alcohol inhibitor increased the drying shrinkage of general cementitious and fine-grained mortars by up to 33 % and 39 %, respectively, and reduced compressive strengths by 47 % and 26 %. However, it did not significantly affect water absorption. In contrast, the sodium gluconate inhibitor increased water absorption in all repair mortars but notably decreased drying shrinkage by up to 47 % in polymer-modified mortar and 66 % in alkali-activated mortar. Despite the variations in the properties of repair mortars, OCIs effectively resisted corrosion and delayed crack formation time by up to 400 %. The resistance to corrosion improved with increasing amounts of the inhibitor. The results of this study were used to develop a technical guide for the construction industry, facilitating the selection of appropriate mortar compositions to effectively repair corroded concrete structures and reduce the risk of further corrosion.

Silicomanganese fume-based alkali-activated mortar: experimental, statistical, and environmental impact studies.

This paper evaluates the flowability and strength properties of alkali-activated mortar produced using silicomanganese fume (SiMnF) as the sole binder, combined with alkaline activators and sand, cured at room temperature (23 ± 1 °C). A total of 18 mixes were prepared by varying binder content (370, 470, and 570 kg/m3), alkaline activator content (33, 43, and 53% of binder by weight), and NaOH concentration (8 M and 12 M). The SiMnF-based alkali-activated pastes were characterized using SEM, XRD, and FTIR techniques to study morphology, mineral composition, and functional groups, respectively. Statistical modeling, including analysis of variance (ANOVA) and response surface method (RSM), was performed to optimize the mixes, and a life cycle assessment was conducted to evaluate the environmental impact of the developed SiMnF-based alkali-activated mortars (SiMnF-AAM). The experimental results showed that an optimal mix design with 470kg/m3 SiMnF, 43% alkaline activator content, and NaOH concentrations of 8M and 12M achieved the best balance of flow and strength. XRD and FTIR analyses confirmed that Nchwaningite was the primary reaction product, with secondary phases including magnetite, manganese ferrite, and potassium feldspar, influenced by alkali concentration. The SiMnF-based mixtures had a significantly lower CO₂ footprint (0.08kg CO₂/kg) compared to the cement-based mix, with alkali activators being the primary contributors to emissions. The developed SiMnF-AAM mixes, cured at room temperature, exhibited improved workability, mechanical properties, and reduced environmental impact, making them adaptive to real-life applications.

Optimizing mechanical properties of one-part alkali-activated mortar with recycled plastic and graphene nanoplatelets using response surface methodology

This study aims to optimize the mechanical properties of one-part alkali-activated mortar (OPAAM) containing recycled plastic aggregates (RPA) and graphene nanoplatelets (GNP) using response surface methodology (RSM). Mixtures were prepared with RPA replacing fine aggregate in varying proportions from 0 % to 50 %, and GNP added in dosages ranging from 0.1 % to 0.4 % of the binder's weight. The results indicated that RPA substitution reduced the mechanical properties of OPAAM, with compressive strength decreasing by 27.5 % and 46.9 % for mixtures with 25 % and 50 % RPA, respectively, compared to the control mixture. However, the incorporation of GNP significantly improved the mechanical properties and microstructure of OPAAM, mitigating the negative effects of RPA. The maximum compressive strengths were 57 MPa, 38 MPa, and 31 MPa for mixtures containing 0 %, 25 %, and 50 % RPA, respectively, at 28 days, achieved with a 0.2 % addition of GNP. Predicted models were proposed based on RPA and GNP to estimate the strengths and water absorption of OPAAM. These models were found to be significant, with strong correlations in predicting the mechanical properties. The optimal OPAAM mixture was achieved with 10.7 % RPA and 0.2 % GNP. This result was validated experimentally, with the difference between predicted and experimental outcomes being less than 10 %.

Pre-treated municipal solid waste bottom ash as alkali-activated mortar precursor

Pre-treated incinerator bottom ash was used as a precursor of alkali-activated mortars. Control mortars were produced using coal fly ash. Different combinations of alkaline activator were tested (sodium oxide/binder ratio (4%, 6%, 8%, 10% and 15%) and silicon dioxide/sodium oxide ratio (0, 0.5, 1.0, 1.5 and 2.0)) and the influence of these on the mortar's mechanical performance was evaluated. The mortars were tested in both fresh (for density and workability) and hardened states (for dry density, compressive and flexural strengths and modulus of elasticity) after 7, 28, 91 and 182 days. The first stage of work was precursor pre-treatment in a sodium hydroxide solution to prevent the expansion of fresh specimens due to the reaction of aluminium with the alkaline activator. The pre-treatment was effective in preventing excessive hydrogen gas generation during setting, leading to dimensional stability and improved strength. Different optimum sodium oxide contents were observed after 28 days (i.e. 15% for fly ash specimens and 8% for bottom ash specimens). The results of a simplified life-cycle assessment showed that such mixes exhibited lower overall carbon dioxide emissions when compared with cement-based counterparts. However, this trend was reversed with increasing contents of sodium hydroxide and sodium silicate.

Carbon sequestration in earth-based alkali-activated mortar: phase changes and performance after natural exposure

This research investigates the effect of carbon sequestration via accelerated carbon curing (ACC) in alkali-activated earth-based alkali-activated mortar (25S-AAM) on the long-term engineering performance, chemical bonding and microstructure. The addition of clay accelerates hydration kinetics and promotes the formation of more cross-linked calcium–(sodium) alumino silicate hydrates (N-A-S-H and C-(N)-A-S-H). This contributes to early strength and a 25% reduction in total shrinkage after 60 days. Although ACC promotes higher carbon sequestration and increases 1-d compressive strength by 13%, it leads to severe decalcification of 25S-AAM after 365 days of natural exposure, resulting in coarsening of the pore structure in the mesoporous size range of 10–100 nm. Due to a relatively low Ca/Si ratio, 25S-AAM is more adversely affected by natural carbonation during the 365-d exposure period than the control (without clay). In summary, ACC is not recommended for earth-based AAM products especially if they are applied for outdoor constructions.

Mechanical and shrinkage properties of alkali-activated mortars with graphite tailings

To improve the problems of high CO2 emission generated by the preparation of silicate cement, large accumulation of solid waste, and depletion of natural sand resources, this paper investigates the effect of pozzolanic effect of graphite tailings (GT) on the mechanical properties, shrinkage properties and microstructure of alkali-activated mortar, and less research has been done on this related content. This paper partially replaced the natural sand with GT, and completely replaced the cement with fly ash and slag to prepare alkali-activated fly ash-slag (AAFS) mortar. The consequences of GT replacement rate on the mechanical and shrinkage characteristics of AAFS mortar were analyzed. In addition, X-ray diffraction (XRD), mercury-in-pressure (MIP), and nuclear magnetic resonance (29Si MAS NMR) were used to examine the hydration degree, pore structure, and hydration products of AAFS mortar. The results demonstrated when the Na2O content was 7 % and the activator modulus was 1.0, the test group's 28-day flexural and compressive strengths at a 20 % GT replacement rate were increased by 19.49 % and 14.45 %, respectively, compared to the test group without GT. The appropriate quantity of GT reduced the AAFS mortar's drying shrinkage and increased the AAFS mortar's self-shrinkage. According to the microstructure analysis, GT had a pozzolanic effect: moderate doping of GT promoted the hydration reaction of precursors, improved the amount of C-(A)-S-H gel product generated, and improved AAFS mortar's mechanical and shrinkage properties.

Exploring the rheological and mechanical properties of alkali activated mortar incorporating waste foundry sand: A comprehensive experimental and machine learning investigation

Alkali-activated materials, known for their economical and eco-friendly nature, are becoming popular as a viable substitute for traditional cement-based materials in the field of construction. This research thoroughly examines the intricate rheological characteristics and compressive strength (CS) of alkali-activated mortar (AAM). It specifically explores the use of waste foundry sand (WFS) as an environmentally conscious and sustainable alternative to river sand. The addition of WFS significantly improves the CS of AAM, demonstrating 35 % enhancements at a 30 % sand replacement level. The rheological properties of customized AAM mixtures were targeted to achieve optimal use in 3D printing. The increasing replacement level of WFS in the matrix induced a non-linear reduction in yield stress (37 % decrease at 30 % replacement) accompanied by a concurrent rise in plastic viscosity (38 % increase at 30 % replacement). Considering the intricate interplay between rheological parameters and CS, AAM containing 15 % sand replacement exhibited optimal properties. Moreover, through rigorous experimentation, a comprehensive dataset of 64 samples was established by varying the amount of river sand, WFS, and water content in the mix. Machine learning models—including AdaBoost, decision tree, K-nearest neighbors, stochastic gradient descent, gradient boosting, random forest, neural network, gene expression programming, and support vector machine—were developed to predict CS, yield stress, and plastic viscosity of the AAM. Modeling errors, including MSE, RMSE, MAE, and MAPE, were falling in the acceptable limits. Specifically, most models demonstrated a high level of prediction having R2 > 0.90 across training and validation datasets. In conclusion, this study not only highlights the optimized properties of AAM but also validates the efficacy of various machine learning models in predicting crucial parameters for AAM formulation.

Utilization of sulfur iron ore tailing (SIOT) in GGBS-metakaolin based alkali-activated mortar

A series of laboratory tests were conducted to investigate the possibility of using sulfur iron ore tailings (SIOT) in GGBS-metakaolin based alkali-activated mortar (AAM) as grouting material. The results indicate that increasing SIOT content leads to a longer setting time of the mortar. This leads to the activation of SIOT particles within the mortar, thereby creating a denser microstructure. The X-ray diffraction (XRD) patterns reveal more pronounced peaks associated with the calcium-aluminosilicate-hydrate (C-A-S-H) network in specimens containing 25 % and 50 % SIOT and 10 % MK. These specimens demonstrate superior sulfate resistance, freeze-thaw resistance, and reduced drying shrinkage. The compressive strengths decrease nonlinearly with higher SIOT content, likely due to a reduction in calcium ions (Ca²⁺) which impedes the formation of the C-A-S-H network. While the compressive strengths exhibit minimal variation between 3 and 7 days of curing, there is a significant increase after 28 days. The ratios between compressive and flexural strengths of the mortar specimens exceed 4.5. Poorly crystallized gypsum was observed in the XRD patterns, resulting from the interaction between sulfates from SIOT and Ca²⁺ from GGBS, which may influence the overall performance of the mortar.

Preparation and properties of alkali-activated fly ash-waste brick porous building materials

This study explores the development of sustainable porous building materials through the alkali-activation of fly ash and waste clay brick powder. Utilizing Class F fly ash and brick powder from demolished buildings, a series of alkali-activated mortars with varying brick powder replacements (0 % to 50 % by mass) were formulated and analyzed. The results reveal that a 10 % brick powder replacement optimizes the compressive strength, reaching 73 MPa at 28 days, attributed to enhanced nucleation and calcium-rich gel formation. However, higher brick content reduces strength due to the dilution of key reactive materials, with a 50 % replacement leading to a strength of 27 MPa. Porosity increases proportionally with brick content, achieving a maximum of 42 % at 50 % replacement, suggesting potential applications in insulation-centric scenarios. Microstructural analysis confirms the formation of a porous network and identifies the phase compositions and reaction products. This research demonstrates the potential of repurposing construction waste into efficient and environmentally friendly building materials, contributing to waste reduction and offering a greener alternative to traditional practices.

Strength and workability of one-part sodium carbonate activated mortar incorporated with silicomanganese slag

This research utilized sodium carbonate (Na2CO3) as an alkaline activator to produce one-part alkali-activated mortar (AAM) with silicomanganese (SiMn) slag as the aluminosilicate precursor. In the experiment, the effect of Na2CO3 dosage (4 %, 6 %, 8 %, 10 %, 12 %) and binder replacement with ordinary Portland cement (OPC) (10 %, 30 %, 50 %) on the compressive strength and workability of AAM was investigated. To improve the workability, several types of superplasticizer (SP), including MasterGlenium ACE 389 (MG) and sodium naphthalene sulfonate formaldehyde (SNSF), and retarder, including REAL SET 231 (RS231) and vinegar (acetic acid), were incorporated. The relationship between strength and workability of one-part AAM was also established. The results showed that increasing the Na2CO3 content from 4 % to 10 % improved the strength by about 2 times but reduced workability by 7.8 % due to the increased alkalinity and OH− concentration. The incorporation of up to 50 % OPC further increased the strength by 3.2–5.3 times due to the synergetic effect of alkali activation of SiMn slag and cement hydration. In addition, SNSF-type SP outperformed MG-type SP in terms of workability and compressive strength. Both the RS231 retarder and acetic acid enhanced the workability by 8%–48 % and strength by 10.5 %–28.3 %. A quadratic regression equation with R2 values of 0.58–0.81 was developed to correlate the strength and workability of one-part AAM.

Optimisation of the performance of alkali-activated mortars using CDW binders from different sources

This study investigates the fresh-state properties and the hardened-state physical and mechanical properties of a total of 64 alkali-activated mortars incorporating different wastes as binders, such as fly ash (FA), recycled concrete (RC), recycled brick (RB), and recycled tile (RT). These waste materials were activated using sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). Linear regression analysis was employed to evaluate the impact and significance of Na2O concentration (9 % or 15 %), modulus of silica (0.5 or 1), curing time in the oven (24 or 48 h), and temperature (50 °C or 70 °C) on the properties of the mortars. The results, analysed using ANOVA, indicate that all properties were affected by these parameters, except for the initial curing time in the oven for mortars made with construction and demolition waste (CDW), which showed no significant differences between periods of 24 and 48 h. Compared to mortars produced with RC, the contribution of these parameters to mechanical properties was more prominent in the mixes with RT and RB. The highest compressive strength at 28 days, for the mortars with CDW binders, was obtained by incorporating RT with 12 % of Na2O, modulus of silica of 1 and 70 °C for 48 h of initial curing, reaching 12.5 MPa. This value is 2.1 times higher than the strength obtained in mixes with RB or RC. The results also show that the performance of the mortars is highly related to the reactivity of the waste material (mortars with RT performed better) and prove that each raw material has its own optimum criterion.

Optimizing Alkali-Activated Mortars with Steel Slag and Eggshell Powder

Optimizing Alkali-Activated Mortars with Steel Slag and Eggshell Powder

Mechanisms of alkali-activation of limestone: Reaction kinetics and influence of drying parameters

This paper focuses on the study of the reaction between limestone and sodium hydroxide solution. This reaction is used to produce alkali-activated mortars after curing and in the presence of unreactive siliceous sand. The kinetics of this reaction is investigated by semi-adiabatic calorimetry experiments. The formulation parameters are fixed but the curing parameters are tested: temperature (38 and 45°C) and time of drying (14, 25, 27 and 28 days). Their impact on reaction products (identified by FTIR and thermal analysis), on microstructure (SEM observations and porosity measurements) and on mechanical strength (flexural and compressive tests) are determined. The reaction was fast and a temperature drying was required to obtain stabilized hydration products in mortars. The products of the alkali-activation of limestone are double sodium/calcium carbonate (mainly pirssonite and with specific conditions of curing gaylussite) and calcium hydroxide. The microstructure and the proportions of reaction products, impacted by drying conditions, influence the mechanical strength of mortars. With an appropriate time (25 days) and temperature of drying (45°C), the compressive strength reached, after 28 days, almost 25 MPa.

Effects of elevated temperature on mechanical properties and microstructures of alkali-activated mortar made from low calcium fly ash-calcium carbide residue mixture

This research investigated the high-temperature resistance of alkali-activated mortar (AAM) using Class F fly ash (FA) blended with calcium carbide residue (CR) as a binder. The FA was blended with CR at 15 %, 30 %, and 45 % by weight. Sodium hydroxide (NaOH) and sodium silicate solution (Na2SiO3) was used as activator in the ratio of 2:1 by weight. The sodium hydroxide solution concentrations were 6, 8, and 10 M, the liquid-to-binder ratio was 0.85, and the binder-to-fine aggregate ratio was 1:2.75 by weight. The study assessed physical characteristics, compressive strength, weight loss, and microstructural analysis, subsequent to being subjected to 2-hour heating at 400, 600, and 800 °C. According to the findings, the highest compressive strength (prior heating) was recorded as 41.3 MPa after 28 days and this was observed in samples where 30 % of CR was combined with 70 % of FA. Meanwhile, when exposed to elevated temperatures, the compressive strength of all samples was decreased. The decomposition of Ca(OH)2, C-S-H, and C-A-S-H gel in the matrix as indicated by the microstructure result was conformed to the result of compressive strength loss. Nonetheless, when the samples were sintered at 800 °C, a new crystalline phase was formed, resulting in a slightly increase in compressive strength compared to samples sintered at 600 °C.

A multi-performance comparison between lime, cementitious and alkali-activated TRM systems: Mechanical, environmental and energy perspectives

The combined need to propose new solutions for the structural reinforcement of existing buildings and for the reduction of CO2 emissions is leading to the development of more sustainable composite materials, such as those based on alkali-activated mortars (AAM). In this study, different formulations of AAM, based on metakaolin or fly ash, have been evaluated as possible matrices for Textile Reinforced Mortar (TRM) systems. Two different bidirectional textiles, made of AR glass or basalt fibers, were used as internal reinforcement. The physical-mechanical properties of TRM systems based on AAM were evaluated and compared with those of commercial systems with cementitious or lime-based matrices. Direct tensile tests on TRM coupons and shear bond tests on clay brick substrates were carried out. Then, their energy and environmental-related performance have been compared. Results showed that alkali-activated matrices can be very promising and eco-friendly alternative solutions to traditional mortars in TRM systems.

Resistance to magnesium sulphate attack of binary and ternary cementless self-compacting alkali-activated mortar

The aim of this study is to investigate the effect of sulphate on self-compacting alkali-activated mortars (SCAAMs) produced using volcanic scoria (V), boron waste (B) and granulated blast furnace slag (G) together with alkali activators. Thus, the production of cement-free alkali-active mortar by recycling waste and reducing the CO2 effect increases the importance of this study. The fact that the waste material is provided free of charge and that V is readily available from nature provides economic advantages in the production of these mortars. In this experimental study, magnesium sulphate solution was utilized to define the sulphate resistance of SCAAMs. In binary SCAAMs, B was used with G in a ratio of NS:NH = 3.0, with an increase from 5 % to 15 %; in ternary mixtures, B was used together with G and V in the same proportions, in a ratio of NS:NH = 1.0. The tests involved immersion in 5 % magnesium sulphate solution for 1, 3 and 6 months. Mass development, compressive strength, visual inspection and microstructural changes were investigated. In general, the binary SCAAMs performed better in magnesium sulphate solution than the ternary SCAAMs, except in the 6th month. Considering the samples with the highest B content, a 100 % loss of compressive strength occurred in the B15G85 sample under the influence of sulphate for 6 months, while a loss of compressive strength of about 15 % occurred in the B15G40V45 sample. The results showed that the increase in B content caused a severe deterioration of the sulphate effect in the samples over time and that the V additive had a positive effect on the sulphate resistance.

Viability of hybrid and alkali-activated slag materials for thermal energy storage: Analysis of the evolution of mechanical and thermal properties

Technological progress is needed to develop renewable energies. Improvements should be especially focused on the energy storage element to help correct the mismatch between energy supply and demand. In concentrated solar power (CSP) plants, ordinary concrete made of Portland cement (PC) has been proven to be a good thermal energy storage (TES) medium. However, the substantial environmental impact of PC manufacturing makes it necessary to develop new materials. Thus, in this work, alternative alkali-activated mortars (AAM) and hybrid materials (HM) have been developed using blast furnace slag to replace PC. This has been done in order to study their stability at high temperature (up to 500 °C) and their viability to operate as TES, undergoing thermal cycles between 200 °C and 400 °C, as they would in CSP technologies. Studying the mechanical and thermal properties after the thermal treatments has revealed that the alternative materials offer improved mechanical properties as well as very good thermal conductivity and storage capacity values. In particular, the best results in terms of mechanical properties were achieved by the AAM system, where the compressive strength value is increased with respect to the reference PC sample by 195% after exposure to 500 °C and by almost 97% after 20 thermal cycles between 200 °C and 400 °C. Furthermore, in terms of thermal properties, the AAM system showed a 31% increase in thermal conductivity after thermal exposure compared to PC. In addition, both AAM and HM systems demonstrated substantial improvements in specific heat and thermal storage capacity, outperforming PC by up to 46% during CSP-like thermal cycles. These promising results open new doors to the study of these alternative materials, such as TES, as they are more suitable than PC from an operational point of view.

Sustainable use of boron waste and volcanic scoria in slag-based self-compacting alkali-activated mortars: Fresh, mechanical and durability properties

Sustainable self-compacting alkali-activated concrete (SCAAC) manufacturing is an environmentally friendly concrete that has a reduced carbon footprint than ordinary concrete. Alkali-activated binders have been demonstrated in experiments to reduce concrete's energy consumption and carbon emissions by over 50%. This paper focuses on manufacturing boron waste (BW), volcanic scoria (VS) and ground blast furnace slag (GBFS) incorporated binary and ternary blends of self-compacting alkali-activated mortars (SCAAM). The main objective of this study is to investigate the fresh, mechanical, durability and microstructural properties of SCAAM based on binary and ternary mixtures of BW, VS, and GBFS. SCAAM samples were synthesized at 60 °C and 100 °C for 72 h then exposed to ambient cured at 3, 28 and 90 days. The compressive strength, flexural strength, physical, and sorptivity properties of the SCAAM mixtures, as well as flowability, were investigated. The performance of the produced blends at freeze-thaw exposure were also examined. SEM, and EDS was also used to examine the microstructures of the mixtures. The findings showed that 50% GBFS and 50%VS based SCAAM mixture heat cured at 100oC activated with NS/NH ratio of 3.0 produced a compressive strength of 40 MPa at 90 days. The findings indicated that inclusion of BW to the SCAAM mixtures decreased the compressive strength notably regardless of NS/NH ratio and curing temperature. Inclusion of BW also affected the durability performance negatively.

Reusing thermoactivated waste paste/concrete powder for sustainable alkali-activated materials: Effects of thermoactivated temperature

The construction waste powder encompasses waste paste powder (WPP) and waste concrete powder (WCP), exhibiting an irregular microstructural morphology and containing mineral constituents like portlandite, C-S-H gel, calcite and quartz. Under the influence of thermal activation, certain hydrated products within construction waste powder undergo decomposition, concurrently generating new substances like CaO and C2S, which contribute to enhanced reactivity. Minerals within construction waste powder participate in polymerization reactions under alkali activation. Furthermore, alkali-activated mortar produced from thermally treated construction waste powder generate an increased quantity of C-A-S-H/N-A-S-H gel, resulting in a denser microstructure. When construction waste powder is thermally treated at temperatures ranging from 600°C to 800°C, the resulting alkali-activated construction waste powder mortar (AAWM) exhibits higher compressive strength. For example, the 28d compressive strength of AAWM prepared with WCP subjected to heat treatment at 800°C increased by 195.69 % compared to AAWM prepared with untreated WCP. With the increase in thermal treatment temperature of construction waste powder, the drying shrinkage of the resultant AAWM progressively diminishes, along with a gradual reduction in porosity and water absorption. For instance, the porosity and water absorption of AAWM prepared with WCP treated at 800°C decreased by 15.58 % and 18.67 % respectively compared to AAWM prepared with untreated WCP. At a thermal treatment temperature of 800°C, AAWM exhibits strong resistance to chloride penetration. Particularly, AAWM containing WPP outperforms that containing WCP in terms of chloride resistance. Consequently, this study reveals that alkali-activated materials prepared using thermally treated waste powder exhibit commendable mechanical and durability properties.