Silicate Modulus Research Articles

Autogenous shrinkage and hydration property of alkali activated slag pastes containing superabsorbent polymer

In this paper, the superabsorbent polymer (SAP) was applied as internal curing agent to study its effect on the autogenous shrinkage and hydration property of alkali activated slag (AAS) pastes. Liquid absorption and release processes of SAP in AAS pastes were characterized by 1H nuclear magnetic resonance (1H NMR). Moreover, the microstructure and mechanical strength of AAS pastes containing SAP were also revealed. The results showed that the autogenous shrinkage of AAS pastes containing SAP was reduced by about 80.6%, 72.1% and 72.6%, respectively as the silicate modulus (Ms) increased from 0.8 to 1.4. The addition of SAP delayed the second exothermic peak, but increased the cumulative heat of AAS pastes. In addition, internal curing by SAP could promote the generation of C-A-S-H gels and hydrotalcite-like phases and increase the reaction degree of slag, particularly for AAS pastes with higher Ms, being attributed to the continuous release of entrained water and alkali activator solutions in SAP with the increase of hydration time. Furthermore, the addition of SAP would increase capillary pore size and pore volume of AAS pastes, and thus lead to the decrease of compressive strength.

A high value utilization process for coal gasification slag: Preparation of high modulus sodium silicate by mechano-chemical synergistic activation

Coal gasification coarse slag (CGCS) is solid waste generated during coal gasification. The mainly treatment method of CGCS is storage and landfill, which causes severe environmental pollution and waste of land resources. Sodium silicate can be synthesized using CGCS after impurities are removed for the high content of amorphous silica. In this work, a novel method of acid activation depolymerization–dilute alkali dissociation is proposed to synthesize high-modulus, low-impurity sodium silicate using CGCS under mild conditions. In the acid activation depolymerization process, the content of impurities such as CaO and Fe2O3 can be reduced from over 30% to below 3%. SiO2 composition can be enriched from 35.75% to 60.60%. The SiOAl bond is broken, the coordination structures of Q4(2Al) and Q4(3Al) are depolymerized, and the reactive Q4(0Al) and Q3(0Al) coordination structures of amorphous silica are formed. Numerous defects appear in the aluminosilicate structure, exposing a large number of active SiOH bonds. Efficient desilicated ratio is increased from 7.59% to 73.45%. During the process of dilute alkali dissociation, a large number of reactive SiOSi bonds with network structure defects are broken with the destruction of hydroxyl groups, while SiO and SiOH bonds are formed. Amorphous silica is leached into the liquid phase in the form of oligomers, and high-modulus sodium silicate can be obtained. Under optimal conditions, the removal ratio of amorphous silica and modulus of sodium silicate can reach 80% and 3.53, respectively. The synthesized sodium silicate can be used to produce hydrated silica, adhesives and surface coatings. This process not only reduces pollution, but also alleviates the shortage of high-purity quartz sand resources and promotes the clean development of coal chemical enterprises.

Fracture Resistance of AAAS Composites with Ceramic Precursor

The paper deals with selected alkali-activated aluminosilicate (AAAS) composites based on ceramic precursors in terms of their characterization by mechanical fracture parameters. Composites made of brick dust as a precursor and an alkaline activator with a silicate modulus of Ms = 0.8, 1.0, 1.2, 1.4 and 1.6 were investigated. The filler employed with one set of composites was quartz sand, while for the other set it was crushed brick. The test specimens had nominal dimensions of 40 × 40 × 160 mm and were provided with notches at midspan of up to 1/3 of the height of the specimens after 28 days. 6 samples from each composite were tested. The specimens were subjected to three-point bending tests in which force vs. displacement (deflection at midspan) diagrams (F–d diagrams) and force vs. crack mouth opening (F–CMOD) diagrams were recorded. After the correction of these diagrams, static modulus of elasticity, effective fracture toughness, effective toughness and specific fracture energy values were determined using the Effective Crack Model and the Work-of-Fracture method. After the fracture experiments, informative compressive strength values were determined from one of the parts. All of the evaluations included the determination of arithmetic means and standard deviations. The silicate modulus values and type of filler of the AAAS composites significantly influenced their mechanical fracture parameters.

Use of Ash after Denitrification as an Additive to Concrete Based on Alcali-Activated Slag

This paper deals with the possibility of using fly ash after denitrification by the SNCR method a partial replacement in alkali-activated concrete based on blast furnace granulated slag. Previous research has verified the use of fly ash after denitrification in alkali-activated materials based on blast furnace granulated slag, and so far no negative effects on the properties of these mixtures have been found. The tests were performed on cement test specimens. As part of the preparation of concrete mixtures, two recipes were prepared. The first reference mixture contained only blast furnace granulated slag activated by sodium water glass with silicate modulus of 2. The second recipe was modified by replacing of 30% slag by fly ash after denitrification by SNCR method. Within the strength characteristics, the reference mixture always achieved better results. Very slow increases in strength were recorded for the mixture with 30% slag replacement by fly ash, when the compressive strength after 7 days of maturation was only 4.5 MPa.

Strength of AAAS Composites with Ceramic Precursor over Time

The paper deals with the approximation of the time evolution of the strengths of selected alkali-activated aluminosilicate (AAAS) composites based on ceramic precursors. Composites made of brick dust as a precursor and an alkaline activator with a silicate modulus of Ms = 0.8, 1.0, 1.2, 1.4, and 1.6 were investigated. The filler consisted of standard quartz sand in one case, and crushed brick in the other. The test specimens had nominal dimensions of 40 × 40 × 160 mm and were tested in three-point bending after 7, 28, 90, and 300 days of maturation. From each composite, 3 specimens were tested and the compressive strength was determined from the 6 specimen parts that remained after the bending tests. The obtained flexural and compressive strength values for the abovementioned 4 composite ages were approximated by the exponential function , where the coefficient a represents a horizontal asymptote to the approximation curve, i.e. the theoretical strength of the composite at time t = ∞; the exponential term of the approximation with the coefficients b and c expresses the degree of the time-dependent change of the respective compressive strength in the interval t = (0, ∞). The approximation was performed with the least squares method using genetic algorithms implemented in the Java GA package with open source code.

Identification of AAAS Composites Mechanical Fracture Parameters

The paper deals with selected alkali-activated aluminosilicate (AAAS) composites based on ceramic precursors in terms of characterization by mechanical fracture parameters. Two composites made of brick dust as a precursor and an alkaline activator with a silicate modulus Ms = 1.0 were investigated. The composites differed in the fineness of grinding of the precursor – in the first set it was 0 to 1 mm, in the second set 0 to 0.3 mm. The filler was crushed brick. The test specimens had nominal dimensions of 40 × 40 × 160 mm and were provided with notches in the middle of the span up to 1/3 of the depth of the specimens after 28 days of hardening. Five to six specimens from each composite set were tested. The specimens were subjected to three-point bending tests, in which force vs. displacement (deflection in the middle of the span) diagrams (F–d diagrams) and force vs. crack mouth opening displacement (F–CMOD) diagrams were recorded. After correction of these diagrams, the values of static modulus of elasticity, effective fracture toughness, effective toughness and specific fracture energy were determined using the Effective Crack Model and the Work-of-Fracture method. After the fracture experiments, the values of informative compressive strength were determined on one of the fractured parts. At the same time, the values of static modulus of elasticity, tensile strength and specific fracture energy were identified using artificial neural networks and F–d diagrams measured and simulated in the ATENA FEM software. All evaluations included the determination of basic statistics of parameters.

Influence of molarity and alkali mixture ratio on ambient temperature cured waste cement concrete based geopolymer mortar

Generation of an enormous amount of construction and demolition (C&D) waste due to rapid growth in the infrastructure segment globally is a matter of dire concern for the present decade due to poorly managed disposal to re-utilization. The present study focuses on the formulation of an effective utilization regime of C&D waste (cement concrete) for its re-consumption as geopolymer mortar. Formulation of different molarities of sodium hydroxide (6 M to 16 M) and alkali mixture ratio of sodium silicate to sodium hydroxide solution (1.5, 2.5 and 3.5) have been done and cured for 90D at controlled ambient temperature. The samples were tested for fresh and hardened properties. The effect of silicate modulus and Na2O% with different alkali proportions on the hardened properties were studied. The results reveals that the optimum compressive strength of 20.7 MPa is achieved at a silicate modulus of 1.54 and Na2O% of 12.5%. Further microstructural analysis (mineralogical, elemental, thermal and bonding types) has been done to better comprehend the interactive performance of C&D waste with the change in alkali quantities. The physicochemical and microanalysis reveals that molarity, dissolution of aluminosilicates, and mineralogical compositions are the main factors governing the outcomes while keeping the curing regime at ambient temperature.

Orthogonal experimental study on preparation of water glass from biomass ash

Using fly ash from biomass power plant as raw material, sodium silicate was prepared by alkali melting method under normal pressure. Orthogonal experiments were designed to explore the effects of NaOH solution concentration, solid-liquid ratio (ratio of NaOH solution volume to biomass ash mass), reaction temperature and reaction time on the dissolution rate of SiO2 and the modulus of sodium silicate. The results showed that the optimal solution was NaOH concentration of 1mol/L, solid-liquid ratio of 1:4, reaction temperature of 120°C and reaction time of 4 hours. According to the experimental verification, the dissolution rate of silicon dioxide and the modulus of water glass in the optimal scheme reach 56% and 2.43, respectively, which is the best experimental condition.

Synthesis of sodium silicate using industrial by-products glauber's salt and microsilica: Effective reuse of the waste.

Large amounts of by-products, including glauber's salt (GS) and microsilica (MS), are accumulated from chlor-alkali industry and ferrosilicon industry development, which not only wastes precious resources, but also causes serious environmental problems. In order to recycle and reuse these industrial by-products, solid sodium silicate was synthesized using GS and MS as the main raw materials, and semi-coke (SC) as the reducing agent. The effects of melting parameters including GS/SC and MS/GS molar ratio, heating rate, temperature, reaction time, and SC particle size on the conversion efficiency and modulus of solid sodium silicate were investigated and optimized. Under optimal conditions, the maximum conversion efficiency of 94.91% was obtained with modulus of 2.5. Characterization analysis of the products indicated that the amorphous silicate sodium was successfully synthesized. Moreover, the reaction mechanism was investigated, which focused on the thermal behavior and phase transformation using thermo-gravimetric and differential scanning calorimetric (TG-DSC) and in-situ X-ray diffraction. Additionally, the causes and suppression measures of "glauber's salt water" (GSW) during the experiment were summarized. This work not only creates resource utilization of GS and MS, but also provides the foundation for the synthesis of sodium silicate with GS.

Silica extraction from bauxite reaction residue and synthesis water glass

Abstract Bauxite reaction residue (BRR) produced from the poly-aluminum chloride (PAC) coagulant industry is a solid acidic waste that is harmful to environment. A low temperature synthesis route to convert the waste into water glass was reported. Silica dissolution process was systematically studied, including the thermodynamic analysis and the influence of calcium and aluminum on the leaching of amorphous silica. Simulation studies have shown that calcium and aluminum combine with silicon to form hydrated calcium silicate, silica–alumina gel, and zeolite, respectively, thereby hindering the leaching of silica. Maximizing the removal of calcium, aluminum, and chlorine can effectively improve the leaching of silicon in the subsequent process, and corresponding element removal rates are 42.81%, 44.15%, and 96.94%, respectively. The removed material is not randomly discarded and is reused to prepare PAC. The silica extraction rate reached 81.45% under optimal conditions (NaOH; 3 mol L−1, L S−1; 5/1, 75°C, 2 h), and sodium silicate modulus (nSiO2:nNa2O) is 1.11. The results indicated that a large amount of silica was existed in amorphous form. Precipitated silica was obtained by acidifying sodium silicate solution at optimal pH 7.0. Moreover, sodium silicate (1.11) further synthesizes sodium silicate (modulus 3.27) by adding precipitated silica at 75°C.

Potential utilization of sugarcane bagasse ash for developing alkali-activated materials

Sugarcane bagasse ash (SBA) is a by-product generated from cogenerations in sugar industries. This study is aimed at investigating on performance of alkali-activated binder using SBA and ground blast furnace slag (GBFS). The proposed mixtures were developed by changing GBFS/SBA ratios in blends (i.e. 100/0, 90/10, 80/20, 70/30, and 60/40) and silicate moduli (Ms = 0.6, 0.8, 1.2). Several results are highlighted: (1) alkali-activated GBFS/SBA pastes perform a quick hardening with an increase in Ms ; (2) testing specimens cured in room–air ambient have the 28-day compressive strength beyond 110 MPa; and the 90/10 one shows the highest mechanical strength and manifested the best sulfate resistance and the lowest water absorption; (3) magnitude of drying shrinkage is smallest for 80/20 sample and following by the 90/10 sample. In summary, with balance of fresh behavior, strength, and shrinkage, a substitution up to 20% SBA could be appropriate to manufacture a sustainable binder.

Increase the Performances of Lime Finishing Mixes Due to Modification with Calcium Silicate Hydrates

Lime plaster mixes are becoming more and more popular in the world’s building materials market every year. Therefore, the issue of increasing the efficiency of lime finishing coatings is relevant. The paper aim is the modification of lime binders with specially synthesized calcium silicate hydrates (CSHs). To obtain the CSH filler, liquid sodium glass was used with a silicate module of 1.53–2.9 and a density of 1130–1663 kg/m3. Using differential thermal analysis (DTA), X-ray diffraction (XRD) patterns, synthesized calcium silicate hydrates, as well as dry plaster mixes, and finishing coatings based on using them were studied. The regularities of the filler synthesis were established depending on the temperature, density, and silicate modulus of liquid glass, the amount of the precipitant additive, the rate of its introduction, and the drying mode. As a result of processing the obtained experimental data, a mathematical model was obtained for the composition “lime + CSH”. The phase composition of the filler was revealed, which is characterized by the presence of calcium silicate hydrates of the tobermorite group, a solid solution CSH (B) in the form of a weakly crystallized gel, a solid solution of C–S–H (II), hydrohalites, and calcites. It was found that the use of the fillers into the lime compositions, obtained with the rapid introduction of CaCl2 additive into water glass during the synthesis of the filler, promotes the acceleration of the plastic strength gain of lime compositions. It was revealed that the lime composites with the CSH filler are characterized by reduced shrinkage deformations up to 45%. The introduction of the CSH filler into the lime compositions increases the water resistance of the lime finishing layer by 36%. A technological scheme for the production of the lime dry plaster mixes has been developed; it can be introduced at existing factories of building materials without significant re-equipment of production.

Structured sand-sodium-silicate mixtures gluing with sodium silicate solute

Purpose – method of gluing with pure silicon silicate solute (SSS) molds and cores made of structured sand-sodiumsilicate mixtures (SSSM) investigation, which solidification has been realized by microwave radiation, and engineering method for calculating the minimum admissible tensile strength of gluing joint for structured mixtures elaboration. Methodology. Quartz sand grade 1K3O3016 and RS (GOST 13078-81) with silicate modulus of 2.9 and specific density of 1.44 g/cm3 has been used in this study. Samples processing that were glued with microwave radiation have been carried out in microwave furnace with nominal magnetron power of 700 and 900W and radiation frequency of 2.45GHz.Mixtures tensile strength has been determined on LRu-2e device using figure-eight samples. Results. Method for minimum admissible tensile strength of gluing joint calculating has been developed. Taking into account its value in casting molds and rods manufacturing development will ensure molten-filled molds integrity and prevent rods displacement or separation installed in them. It has been established that pure silicon silicate solute can be used as gluing material solidifying by microwave radiation for bonding SSSM structured by steam-microwave solidification process (SMS-process).It has not been recommended to use SSS in original form as gluing material solidified by microwave radiation for bonding SSSM structured by convection heat drying. Scientific originality. For the first time, phenomenon of sodium silicate solute and quartz sand saturated with sodium silicate solute in structured SSSM simultaneous transfer during their treatment with steam-microwave radiation and new capillary-porous structures with sodium silicate increased content in them appearance have been established. Practical value. Method for calculating the gluing joint minimum permissible strength under tension will allow to obtain practical data, taking into account which, when casting molds and rods manufacturing technology developing, will ensure molds integrity when they are filled with melt and prevent rods installed in themd is placement or separation. This will generally improve castings quality. Pure SSS applying in casting molds and rods made by SMS-process gluing joints manufacturing will reduce castings production cost due to eliminating of other gluetypes using. Keywords: sodium silicate solute, microwave radiation, mold, rod, mixture, strength, gluing

Influences of Sodium Silicate Modulus on Mechanical Properties and Microstructure of Fly Ash Geopolymer

In order to explore the water glass modulus that can make the fly ash base polymer the highest strength and the best performance, fly ash is used as the raw material to prepare alkali-activated fly ash-based geopolymer test blocks. Through unconfined compression test, SEM test, XRD test, the influence of different water glass modulus and age on its mechanical properties is studied. The results are as follows. When the sodium silicate modulus is 1.1, the strength of fly ash-based geopolymer is the highest, reaching 6.1MPa after 28 days of curing. With the growth of age, the strength of fly ash-based geopolymers continues to increase. It is observed from the SEM test that when the modulus is 1.1, the structure is dense, the porosity is small, the alkali excitation effect is obvious, and the reaction is relatively complete.

Optimization of mix proportion of alkali-activated slag mortars prepared with seawater and coral sand

To effectively utilize marine resources and promote sustainable development in the construction industry, an innovative building material, namely, alkali-activated slag mortars prepared with seawater and coral sand (SC-AAMs), was proposed in this paper, and its workability, setting time, compressive strength, flexural strength, and drying shrinkage were studied. The effects of the modulus of sodium silicate (Ms), Na2O-to-binder (N/B) ratio by weight, replacement ratio of the coral sand for sea sand (Rs), and water-to-binder (W/B) ratio were considered using the Taguchi orthogonal experimental design method. The experimental results indicated that an increased alkali activator modulus and alkaline contents improved the compressive and flexural strengths, however, resulting in a decreased setting time and an increased drying shrinkage. According to the results from the aforementioned orthogonal experiments, the optimum mixtures for SC-AAMs were determined to be an Ms = 1.2, a N/B = 4%, a W/B = 0.45, and a Rs = 100%. Then, the microstructure and crystalline phases in the SC-AAMs prepared with this optimum mix proportion were analyzed using scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively, and the cement mortar mixed by seawater and coral sand was selected as the reference. It can be concluded that the utilization of the alkali-activated materials changed the reaction hydrate products of the mortars and improved the interfacial microstructures between the coral sand and slurry. In addition, the existence of the coral sand reduced the drying shrinkage of the AAMs due to the self-curing effect inside the coral aggregate.

Mechanical Property and Microstructure of Fly Ash-Based Geopolymer Activated by Sodium Silicate

Sodium silicate is one of the common alkali activators of geopolymers. The modulus, concentration and dosage of sodium silicate have significant effects on the activation of fly ash, the strength and microstructure of geopolymer. In this paper, unconfined compressive strength test, X-ray diffraction analysis (XRD), Fourier transform infrared light (FTIR), 29Si nuclear magnetic resonance (29Si NMR), scanning electron microscope and energy disperse spectroscopy (SEMEDS), and physisorption experiment (BET) were carried out to study the effects of the sodium silicate modulus and dosage on the mechanical property and microstructure of fly ash-based geopolymer. The results indicated that the main product of the geopolymer activated by sodium silicate was hydrated sodium aluminosilicate (N-A-S-H). When modulus value decreased and meanwhile dosage of sodium silicate increased, the reorganization and polymerization of gel products were accelerated so that the integrity and continuity of the microstructure of geopolymer were improved, and then the strength increased. When the modulus of sodium silicate was 3.28, the maximum value of the strength was at the dosage of 10%. According to this study, it was investigated that modulus value and dosage of sodium silicate had obvious influence on the alkali- activated reaction of fly ash, which can provide an engineering reference for the special soil solidification with geopolymers.

Sand-sodium-silicate mixtures grains composition optimization for structuring by steam-microwave solidification method

Abstract. Mixture sizes of sand-sodium-silicate conglomerates and sodium silicate solute content in them influences on the basic physical and technological indicators of molding and core mixtures structured in steam-microwave environment have been investigated. Sand-sodium-silicate mixture structured by steam-microwave environment (steam-microwave solidification method – SMS-process) composition has been optimized. Standard and generally accepted methods and techniques of molding mixtures investigation have beenused in this study. For mixtures manufacturing have been used: quartz sand brand 1K2O202; sodium silicate solute with silicate modulus of 2.8…3.0 and specific gravity of 1.42…1.44 g/cm3. Quartz sand cladding has been implemented with 0.5 and 2.5% sodium silicate solute (by weight, over 100% sand). Sand-sodium-silicate conglomerates have been scattered in sieves and conglomerates with sizes less than 0.315mm and with sizes from 0.315 to 0.63mm have been used for research. Mixture composition has been optimized according to results of simplex planning and experimental data by simplex triangles constructing and superimposing their formatted images on each other with darkened fields between isolines that do not meet of each parameters required level. To plot simplex lattices, model with simplex lattice plan of incomplete cube in Scheffe’s triple system has been used. For the first time, influence of mixture sand-sodium-silicate conglomerates sizes and sodium-silicate-solute content in them on basic indicators of mold and rod mixtures structured in steam-microwave environment has been established, and their composition has been optimized. Data obtained will be useful in molds and rods structured by SMS-process manufacturing. They will have predictable indicators of properties that correspond to their allowable level. Optimal composition of sand-sodium-silicate mixture, structured by SMS-process, is mixture of quartz sand, part of which passed through sieve with cell of 0.315 mm and have sodium silicate solute content (МSiO2=2.8…3.0, 2=1.42…1.44 g/сm3) in amount of 1.5% (by weight, over 100% quartz sand). Keywords.Sand, silicon silicate solute, steam-microwave solidification, optimization, conglomerates, strength, gas permeability, crushability, density, beam deflection, knockout energy.

Effect of sodium silicate on the properties of loess stabilized with alkali-activated fly ash-based

It is a common way to prepare geopolymers by sodium silicate alkali activating fly ash. In this paper, the effects of sodium silicate with different moduli and Baume degrees on the engineering properties and microstructure of loess solidified by alkali -activated fly ash-based geopolymers were studied by unconfined compressive strength test, direct shear test, disintegration test, BET tests and water absorption test. The conclusions are as follows: As the modulus decreases and the Baume degree of sodium silicate increases, the optimal moisture content of the loess decreases, the maximum dry density, the compressive strength and cohesion increases. The lower the sodium silicate modulus and the larger the Baume degree are, the weaker the disintegration of the geopolymer-solidified loess, the lower the natural water absorption and saturated water absorption, the smaller the average pore diameter, the larger the specific surface area of pores and the larger the nanos scale pore volume are.

Sand-sodium-silicate rods structured by steam-microwave solidification knockout from castings

Purpose.Influence of preheating temperature and sodium silicate solute content in sand-sodium-silicate mixtures structured by SMS-process on their destruction work under knock loading action has been established. Methodology. Quartz sand brand 1K2O202, water, sodium silicate solute with specific gravity of 1.42…1.44 g/cm3 and silicate modulus of 2.8… 3.0 have been used in this work. Mixtures structuring has been realized in microwave furnace with frequency of 2.45 GHz and magnetron power of 0.9 kW. Samples heat treatment has been performed in laboratory resistance furnace in temperature range from 100 to 1100С with sample isothermal tempering at fixed temperature for 45...50 minutes. Samples knockout work has been calculated according to CNIITMASH method. Samples of structured by SMS-process mixtures destruction has been performed on laboratory impact machine brand 5033A. Samples structure has been examined on optical microscope at 100-times magnification. Results. With preheating temperature increasing sand-sodium-silicate mixtures structured in steam-microwave environment by SMS-method, containing from 0.5 to 2.5% sodium silicate solute with modulus of 2.8 ... 3.0, knockout work decreases exponentially. At preheating temperature from 800 to 1100°C it becomes practically zero. Mixtures, preheated to 600°C, knockout work does not exceed 20J. It follows that such rods or their individual parts can be removed from castings by shock-vibration method, even from copper and aluminum based alloys. Knockout the rods or their parts, in which after contact with poured into mold melt temperature did not exceed 600°C, has been recommended to carry out by castings immersing in water. Scientific originality. Mold and core mixtures structuring in steam-microwave environment solves the problem of sandsodium-silicate mixtures, containing sodium silicate solute up to 2.5%, knockout from castings for most foundry alloys used in industry. Practicalvalue. Investigation results will be useful for removal of sand-sodium-silicate rods and molds, structured by the SMS-process, technologies and equipment development.

Development of Low-Alkali, Fly Ash/Slag Geopolymers: Predictive Strength Modelling and Analyses of Impact of Curing Temperatures

The present work analyses the effects of curing temperature (25, 40, 60 °C for 24 h), silicate modulus Ms value (1.5, 1.7, 2.0), and slag content (10, 20, 30, 40 wt%) on the compressive strength development (1, 7, 14, 28 days) of low-alkali geopolymer mortars with matrices from fly ash and blast furnace slag. These data were used to generate predictive models for 28-day compressive strength as a function of curing temperature and slag content. While the dominant variable for the 1-day compressive strength was the curing temperature, the slag content was dominant for the 28-day compressive strength. The ratio of the 1-day and 28-day compressive strengths as a function of curing temperature, Ms value, and slag content allows prediction of the maximal possible curing temperature and shows cold-weather casting to present an obstacle to setting. These data also allow prediction of the 28-day compressive strength using only the 1-day compressive strength.