Compressive Strength Of Geopolymer Mortar Research Articles

Effect of silica fume type on rheology and compressive strength of geopolymer mortar

Silica fume (SF) is widely used in the developing of high-performance geopolymer systems. Previous studies have shown that using different types of SF may have different influences on the performance of geopolymers. What are the key factors (affecting the properties of geopolymers) still need to be clarified? This paper investigated the effects of three types of silica fume (SF1− SF3) with various silica contents (98.0%, 94.7% and 53.1%) and particle sizes (D50: 3.3 μm, 3.1 μm and 11.8 μm) on the rheology and compressive strength of alkali-activated calcium alumina cement (CAC)/fly ash mortar. The incorporation of SF can significantly increase the plastic viscosity. The increase in plastic viscosity was due to the ball-bearing action of the spherical SF particles, which reduced the friction between the particles under shearing. Replacing 20% of the fly ash with SF1 and SF2 improved the compressive strength of geopolymer mortars while the incorporation of SF3 decreased the compressive strength at the same replacement ratio. Inductively coupled plasma (ICP) spectrometry results indicated that the amorphous silica in the SFs was dissolved in an alkali solution. Activators with high concentrations of monomer and dimmer silicon groups may promote the reaction between precursors and activators. The formation of additional aluminosilicate gels reduced the amount of large capillary pores (500 nm to 1000 nm), leading to improved strength. The incorporation of coarse SF3 introduced extra voids in the mixture, as suggested by calculations of packing density, leading to reduced strength.

Optimizing geopolymer mortar for shotcrete applications by focusing on flowability and early-age mechanical characteristics

To facilitate the use of geopolymer materials in shotcrete applications, this study presents the development of a geopolymer mortar and explores its flowability and early-stage mechanical properties. Firstly, 15 groups of geopolymer mortar specimens with 3 liquid-binder ratios (0.70, 0.75 and 0.80) and 5 binder-aggregate ratios (0.225, 0.250, 0.275, 0.300 and 0.325) were developed. Secondly, the P-wave velocity, slump, early-age compressive strength and compressive strength were obtained by ultrasonic pulse velocity test, slump test and uniaxial compressive test. Thirdly, discussion on the effect of liquid-binder ratio and binder-aggregate ratio on P-wave velocity, flowability, compressive strength and early-age compressive strength of geopolymer mortar were carried out. Finally, an optimal mix proportions rang of geopolymer mortar materials that meet the requirements of wet shotcrete technology were proposed. The results show that P-wave velocity, slump, early-age compressive strength and compressive strength increase as the increasing of liquid-binder ratio. The slump, compressive strength and P-wave increase as the increasing of binder-aggregate ratio. Moreover, the optimal binder-aggregate ratios were proposed as 0.244 - 0.321, 0.228 - 0.298, and 0.209 - 0.241 for geopolymer mortar with a liquid-binder ratio of 0.70, 0.75 and 0.80, respectively. Geopolymer mortar in these mix proportions achieves compressive strengths ranging from 28.4 MPa to 41.1 MPa after curing for 1 day and 44.2 MPa to 55.4 MPa after curing for 28 days. The mix proportion of geopolymer mortar proposed in this paper can simultaneously meet the standard requirements for mechanical properties and flowability, demonstrating potential for wet shotcrete applications.

Predicting compressive strength of quarry waste-based geopolymer mortar using machine learning algorithms incorporating mix design and ultrasonic pulse velocity

ABSTRACT The current study aimed to investigate the possibility of predicting the compressive strength of geopolymer mortar by mix design parameters, ultrasonic pulse velocity (UPV) and machine learning techniques. Here the geopolymer mortar is produced from eggshell ash and rice husk ash as precursors, NaOH solution as activator and quarry waste as fine aggregate. Twenty-seven combinations of geopolymer mix and a total of 189 mortar cubes were cast and tested for UPV and compressive strength. Seven different machine learning techniques were used to predict the compressive strength assessment tools: linear regression, artificial neural networks, boosted tree regression, random forest regression, K-Nearest Neighbor, support vector regression and XGboost. Among the diverse machine learning models evaluated in this study, XGboost exhibited remarkable efficacy in forecasting the compressive strength of geopolymer mortar. The investigation conducted using SHAP indicates that the concentration of UPV shows the most substantial influence on the prediction of compressive strength.

KARAKTERISTIK MORTAR GEOPOLIMER BERBASIS FLY ASH KELAS C DENGAN PENAMBAHAN BORAKS

Cement has been widely utilized as a primary material in the construction of structural and architectural elements. The cement factory industry can contribute to 30% of global carbon dioxide emissions. Geopolymers were first introduced by Davidovits in 1979 to represent inorganic polymers produced from geochemistry. Geopolymer materials make use of waste materials such as fly ash as a substitute for concrete binders. In this study, Class C (high calcium) fly ash from the Paiton Power Plant was used. The mix design for geopolymer mortar in this study employed the absolute volume calculation method. Absolute volume calculations are based on the absolute volume proportions of each constituent material within 1 m3. The compressive strength of geopolymer mortar with the addition of 5% borax to the molarity value, the alkali/cementitious ratio showed good performance in the mechanical properties of geopolymer mortar. Alkali/cementitious ratios of 0.3, 0.35, and 0.4 in Class C-based geopolymer mortar with 5% borax addition exhibited good workability, making it suitable for use as a base material in architectural material production.

The Effect of Bottom Ash as Partial Replacement of Fine Aggregate in Different NaOH Molarities on the Compressive Strength of Geopolymer Mortar

This study compared the compressive strength of the geopolymer mortar with different percentages of bottom ash as a replacement for fine aggregate. Fly ash from two sources was blended as raw materials. Sodium silicate (Na2SiO3) and sodium hydroxide (NaOH) were used as alkaline solutions, with a ratio of 2.5 and two NaOH concentrations of 8M and 10M. The percentage of bottom ash was substituted up to 30%. The result indicated that the setting time was longer due to the higher molarity of NaOH. The compressive strength of mortar geopolymer at 10M of NaOH was higher than 8M. Higher percentages of bottom ash significantly decreased the compressive strength. However, at 10M NaOH, the compressive strength was decreased by only 11% (20% of substituting). Increasing the molarity of NaOH decreased the absorption of mortar geopolymer and increased the restrain to sodium sulfate.

Compressive strength of geopolymer mortar on different molarities, liquid binder, and alkaline solution ratios.

This article examines the impact of liquid binder (L/B) ratio, molarities, sodium silicate to sodium hydroxide ratios on the compressive strength of geopolymer mortars. In total 72 trial mixes of geopolymer mortar are prepared with GGBS as base constituent material. In the experimental investigation the molarities varied from 8 to 18 by increment of 2 and liquid binder ratio is varied as 0.35, 0.40 and 0.45. In addition to those two variables, alkaline solution ratios are also changed as 1.5, 2.0, 2.5 and 3.0. From the experimental study it is noticed that the geopolymer mortar with GGBS has shown higher compressive strength. Amongst all the mixes, the specimens with liquid binder ratio of 0.45, alkaline ratio of 2.0 and Molarity 14M of NaOH solution exhibited maximum strength of 52.69 MPa.

Utilization of various ceramic waste as fine aggregate replacement into fly ash-based geopolymer

This study aims to utilize a range of ceramic waste to replace sand as a fine aggregate in fly ash geopolymer. Ceramic waste aggregates comprised of brick (BR), floor tile (FT), roof tile (RT), and sanitary ware (ST) have been employed for river sand replacement at 0 %, 25 %, and 50 %. The development in compressive strength was investigated on geopolymer mortar at the ages of 7, 14, and 28 days. The results showed that incorporating FT, RT and ST aggregates exhibited comparable and even higher compressive strength than natural sand. The optimum compressive strength was achieved at 47.4 MPa for 50 % ST specimen, accounting for a 17.52 % improvement. The microstructure revealed that ST aggregates exhibited better interfacial transition zone (ITZ) than sand aggregate, thereby increasing the compressive strength of geopolymer mortar.

Effect of Acid and Thermo-Mechanical Attacks on Compressive Strength of Geopolymer Mortar with Different Eco-Friendly Materials

This research examined how changing the ratios of certain substances affected the strength and durability of a specific type of building material when exposed to acid and heat. This study used various combinations of zeolite, metakaolin, slag, and Portland cement as primary materials. It also used different amounts of potassium hydroxide (KOH) to make the geopolymer mortar. The concentrations of KOH used were 8 M, 12 M, 14 M, and 16 M. The cement-based material had the highest water absorption. A total of 240 tests were conducted, including 20 samples for each mix design tested at curing times of 7, 14, 21, 28, and 90 days. The results showed that the samples made with slag base material and 8 M mixing design had the highest average compressive strength at 28 and 90 days in the acidic environment test, and the zeolite and metakaolin base material samples had the highest corrosion and weight loss, possibly due to their high specific surface and aluminosilicate origin. The samples made with slag-based material had better resistance and the highest average compressive strength in the 300 °C and 500 °C thermo-mechanical tests. The lowest average compressive strength in the thermal and mechanical stress test was related to the samples made with a metakaolin base material. The tests performed on the samples made with slag base material had better compressive strength than the three other base materials in the acid and heat tests. The zeolite-based mortar lost the most weight under 30% acidic sulfuric water. The findings suggest that changes in the molar ratios of alkaline activators can significantly affect the durability properties and strength of geopolymer mortar, and the slag-based material with an 8 M mixing design had the best performance; also, SEM analysis verified this mechanism.

Microstructural Analysis and Compressive Strength of Fly Ash and Petroleum Sludge Ash Geopolymer Mortar under High Temperatures

The development of sustainable building materials and construction to decrease environmental pollution in both production and operational stages of the materials’ life cycle is appealing to great interest in the construction industries worldwide. This study evaluated the negative effect of temperature up to 1000 °C on the compressive strength and microstructure of fly ash and petroleum sludge ash (PSA) geopolymer mortar. A sodium silicate and sodium hydroxide mixture is used as an activator. The synthesized mortar was investigated using X-ray Diffraction (XRD), Fourier Transformation Infrared Spectroscopy (FTIR), Mercury Intrusion Porosimetry (MIP), and Field Emission Scanning Electron Microscopy (FESEM). As the temperature increased, the compressive strength of the geopolymer mortar decreased. The strength degradation is due to the damage to microstructure because of the temperature-induced dehydroxylation, dehydration thermal incompatibility between geopolymer aggregate and paste of geopolymer mortar at high temperatures. With an increase in temperature, the cumulative pore volume increased. The FESEM image showed the decomposition of the geopolymer matrix started at a temperature of 600 °C. Incorporating PSA in geopolymer mortar could result in an eco-friendly and sustainable environment that may reduce the problems associated with sludge disposal.

Assessment of Fly Ash-Rice Straw Ash-Laterite Soil Based Geopolymer Mortar Durability

Geopolymer is an inorganic form of alumina-silica that is synthesized through materials containing lots of silica (Si) and alumina (Al) originating from nature or from industrial by-products. The geopolymer binder is a two-component inorganic system consisting of solid components that have sufficient amounts of SiO2 and Al2O3 to form compounds such as fly ash, rice straw ash, pozzolan, laterite soil, slag, etc. This study aims to analyze the compressive strength, chemical compositions, and geopolymerization process of geopolymers produced from fly ash, rice straw ash, and lateritic soil bound with an alkaline activator, sodium hydroxide (NaOH), with a concentration of 12 M. The durability of the geopolymer mortar was determined by soaking for 3, 7, and 28 days using water curing and sulphate curing (Sodium Sulphate, Na2SO4, and Sulfuric Acid, H2SO4). The results showed that sodium hydroxide (NaOH) can release silica and alumina in the amorphous phase and can be used as a binder for geopolymer mortar made from straw ash, fly ash, and laterite soil without using oven heat, according to compressive strength, chemical compositions, and the geopolymerization process. The results of this study can be used to support the use of waste materials (fly ash and laterite soil) and local materials (straw ash) as geopolymer mortar-forming materials. Furthermore, it can aid in the development of eco-friendly (environmentally friendly) national infrastructure by eliminating the need for oven heat to initiate the polymerization reaction. However, this research can also be developed to increase the compressive strength of geopolymer mortar, which resembles that of conventional concrete in general. Doi: 10.28991/CEJ-2023-09-06-012 Full Text: PDF

Analysis of Geopolymer Mortar Compressive Strength Based on Fly Ash and GGBFS as Patch Repair Material

Damages that often emerge in concrete include cracks, delamination, spalling, wear, fracture, porous, voids (perforated). These damages need to be repaired, one of which is by patch repair. With consideration of strength and frugality, a self-made repair material was developed using mortar as a base material, i.e., geopolymer mortar. Geopolymer mortar is a mortar with natural materials and materials that have a high content of silica oxide and alumina (such as Fly Ash and GGBFS) as a binder that must be activated with an alkaline activator in the form of sodium hydroxide (NaOH) and sodium silicate (Na2SiO3). The use of Fly Ash and GGBFS as a binder to replace cement in geopolymer mortar has a positive impact from an environmental point of view because it can reduce the use of cement and can reduce environmental pollution due to Fly Ash and GGBFS waste. In this research, the effect of variations in Fly Ash and GGBFS and variations in the molarity of NaOH on the compressive strength of geopolymer mortar were investigated, in order to obtain the optimum composition of the geopolymer mortar mixture that meets the requirements of compressive strength as a repair material. From the results of the research, the maximum compressive strength occurred in GF91 16 M mortar at 56 days of 73.77 MPa was obtained. Geopolymer mortar has a higher compressive strength and a cheaper price when compared to Sika Grout mortar so that the use of geopolymer mortar as a patch repair material is better than Sika Grout mortar in terms of strength and frugality.

Development of sustainable high performance geopolymer concrete and mortar using agricultural biomass—A strength performance and sustainability analysis

Geopolymer concrete is a sustainable substitute for traditional Portland cement concrete. In addition, rising carbon taxes on carbon emissions and energy-intensive materials like cement and lime, impacts the cost of industrial by-products due to their pozzolanic nature. This research evaluates the compressive strength and flexural strength of geopolymer concrete, and the compressive strength of geopolymer mortar. Geopolymer mortar data were used for the strength assessment employing an analytical approach, and geopolymer concrete data were utilized for the strength and sustainability performances. Using artificial neural networks (ANNs), multi-linear regression (MPR) analysis, and swarm-assisted linear regression, compressive strength models were created based on experimental datasets of geopolymer mortar mixes with variable precursors, alkali-activator percentages, Si/Al, and Na/Al ratios. The strength and sustainability performances of geopolymer concrete blends with various precursors were assessed by considering cost-efficiency, energy efficiency, and eco-efficiency. The work’s originality comes from enhancing sustainable high-performance concrete without overestimating or underestimating precursors. Extensive experimental work was done in the current study to determine the best mix of geopolymer concrete by varying silica fume, ground granulated blast furnace slag (GGBS), and rice husk ash (RHA). A scanning electron microscopic study was conducted to understand the geopolymer matrix’s microstructure further. A comprehensive discussion section is presented to explain the potential role of RHA. The replacement of conventional concrete in all its current uses may be made possible by this sustainable high-performance concrete utilizing RHA.

Water absorption characteristics and rate of strength development of mortar with slag-based alkali-activated binder and 25% fly ash replacement

This article presents some of the results of an experimental study that evaluated water absorption characteristics and rate of strength development of geopolymer mortar where the binder consists of alkali-activated slag or slag with 25% fly ash replacement. Samples were cured in air at 22 ± 2 °C and 70% RH. From 1 to 7 days of curing, the increase in compressive strength was higher in mortar with 75%slag + 25% fly ash (S75F25) compared to samples with 100 slag binder (S100). After one day, fly ash begins to develop more N-A-S-H gel and contributes noticeably to strength development. Furthermore, the percentage change in strength development decreased continuously from 7 to 28 days of curing and became negative from 28 to 90 days. Ultimately, the 90-day strength decreased below the 28-day strength in all geopolymer samples. The decrease in strength may be due to loss of moisture causing precipitation of reactants rather than the formation of polymerization products. It was found that a strong linear relationship exists between water absorption of geopolymer mortar samples and the square root of immersion time (t0.5). Water absorption in S100 mortars decreased with an increase in the alkaline activator ratio of Na2SiO3/NaOH. This is because the free silicates from Na2SiO3 react with calcium dissolving from GBS and develop calcium-based hydrate C-(A)-S-H gel, which is typically dense and compact. When S100 mortar samples were cured for 90 days, the relationship between water absorption and t0.5 deviated from linearity, which indicates a coarser pore system and/or cracking, and is consistent with an observed decrease in compressive strength. Water absorption of S75F25 mortar exhibits a stronger correlation with t0.5 and a lower initial rate of water absorption, compared to S100, indicating a finer pore system and lower water absorption. Compressive strength at NaOH molarities of 10 mol/L was higher for S75F25 compared to S100. There is a strong correlation between the initial rate of water absorption and the compressive strength of geopolymer mortar.

Effect of ground concrete waste as green binder on the micro-macro properties of eco-friendly metakaolin-based geopolymer mortar

Upcycling of ground concrete waste powder as green binder is an effective and high-value approach to reducing concrete waste. This study utilized ground concrete waste powder including recycled paste powder and recycled concrete powder for sustainable metakaolin-based geopolymer mortar. Concrete waste powder with irregular particle shape mainly contains hydration products, quartz and calcite. Substituting concrete waste powder for metakaolin reduces the number of alkali-activated cementitious products in blended geopolymer paste, but the nucleation and filling effects of concrete waste powder can improve paste micro-structure. Incorporating concrete waste powder raises the drying shrinkage of geopolymer mortar; recycled paste powder blended geopolymer mortar has higher drying shrinkage than recycled concrete powder blended geopolymer mortar, and the maximum drying shrinkage of geopolymer mortar with 75% recycled paste powder is 178.7% higher than that of geopolymer mortar with 75% recycled concrete powder. The compressive strength first rises and then declines with the rise of concrete waste powder content. Recycled paste powder blended geopolymer mortar has better compressive strength than recycled concrete powder blended geopolymer mortar, and the 28-d compressive strength of geopolymer mortar with 75% recycled paste powder is 34.4% larger than that of geopolymer mortar with 75% recycled concrete powder. Substituting concrete waste powder for metakaolin up to 75% declines the water and chloride ingress in blended geopolymer mortar, and recycled paste powder blended geopolymer mortar has lower water absorption and chloride migration than recycled concrete powder blended geopolymer mortar. Optimizing concrete waste powder type and content can prepare sustainable metakaolin-based geopolymer mortar having superior strength and low transport property.

High quality geopolymer concrete by using binder nano metakaolin

Iraqi Metakaolin was used to produce geopolymer mortar and concrete with high specifications. To convert Kaolin to Metakaolin, the De-hydroxylation process was carried out by burning Kaolin at 700°C. Metakaolin was crushed and ground by a ball mill to obtain the Metakaolin at the nanoscale. The large specific surface area of total nanoparticles gives unique properties during their interaction with an alkali-activated solution to form the geopolymer. Nano metakaolin geopolymer mortar mixtures were manufactured entirely according to specification ASTM C109/C109M-16a with different concentrations of alkaline solution (8 - 10 - 12 – 14) molarity. Through mortar test, it was noted the best result of geopolymer at 12 molarity, gives the advantage of dissolving alumina and silica nanoparticles to forming a geopolymer with high specifications. The highest rate of compressive strength of geopolymer mortar is 73 MPa. But in the geopolymer concrete mix with other nanomaterials replaced as a percentage by weight of the nano metakaolin binder, where incorporated (3%) nano-glass blended with (0.01%) carbon nanotube to observe the superior compressive strength reached 74.7 MPa. The effect of freezing and thawing has been, and no effect on compressive strength. During the water absorption test, observed that the absorbance is close to 1.7 %. The main benefit of the total binder nano metakaolin geopolymer is no heat treatment is used for the polymerization process and obtaining high specifications due to the effectiveness and high pozzolan effect of nanomaterials leads to improving compressive strength and other durability properties.

Effects of Spodumene Flotation Tailings on Mechanical Properties of Acid-Based Geopolymer Mortar

This study focuses on using spodumene flotation tailings (SFT) to prepare phosphoric acid-activated metakaolin geopolymer, in which the replacement of metakaolin (MK) by a high percentage (up to 75 wt.%) of tailings was achieved. The compressive strength of geopolymer mortar was significantly improved with SFT as aggregates. In addition, the mechanical properties could also be enhanced by an increased concentration of phosphoric acid (H3PO4) solution or a decreased aggregate particle size. The optimized geopolymer mortar composite was SFT:MK = 3:1, which was activated by H3PO4 solution with a concentration of 51 vol%, followed by curing at 55 °C for 24 h. On the other hand, properties of the geopolymer mortar could also be affected by the morphology of the aggregates. For example, SFT as aggregates could produce more interconnected pores compared to standard sand. The major chemical structural units of geopolymer mortar were -P-O-Al- and AlPO4, which could be spontaneously generated according to the thermodynamic calculation results. Finally, many aluminum ions and a small amount of silicon ions could be leached from the tailings under acidic conditions.

The study on various temperature condition of fly ash based geopolymer mortar

The present research investigated the curing conditions (ambient and heat curing) and the duration of heat curing which is considered as significant criteria affecting the mortar strength. The geopolymer (GP) sample was cured at several heating temperatures, which were ambient, 60, 80, and 100 °C for a curing time of 24 h in the oven. The samples were then stored at room temperature until the day of testing. Compressive strength (CS) was used to evaluate the mechanical characteristics of GP mortar. Mortar control specimens that hardened at room temperature were used for comparison. The outcomes were established using specimens ages 3, 7, 28, 56, and 90 days after the curing procedure. The study reveals that the CS of GP mortar under heat curing conditions develops polymerization faster as the temperature rises. Comparing curing at ambient temperature to elevated temperatures, it can be determined that temperature has a significant effect in promoting the GP mortar strength increase. In comparison to all other curing conditions, oven curing at 80 °C for 24 h obtained the highest CS (32 MPa) at the age of 90 days. The partial replacement of GGBS under ambient curing conditions yielded a maximum CS of 35 MPa.

Effective of alkaline additives on the geopolymer cements properties as alternative to Portland cement in order to protect environment

Geopolymers are inorganic alumina-silicate materials produced from raw materials, rich in silica (SiO2) and alumina (Al2O3), in combination with an alkaline activator solution. In this study, geopolymer of class C flay ash in ambient curing condition were used form geopolymer mortar and effects of different alkaline activator solutions and variations of associated parameters, were investigated. The obtained results indicated that in ambient curing condition (23±2°C), using sodium hydroxide and sodium silicate as an alkaline activator solution, result in higher 7- and 28-day compressive strength of geopolymer mortar compared to potassium-based (potassium hydroxide and potassium silicate) and combination of sodium and potassium-based alkaline activator solutions, approximately 49% and 145%, respectively. But, in term of 90°C curing condition, potassium-based alkaline activator subject to higher 7- and 28-day compressive strengths. Additionally, simultaneous inclusion of NaOH and KOH led to decline the compressive strength. Also, obtained results of experimental data show that optimal ratio 1.5–2 of SiO2/Na2O were highest compressive strength.

Effect of Different Proportions of Fly Ash and GGBFS on the Compressive Strength of Geopolymer Mortar

Nowadays, geopolymer plays a significant role in developing eco-friendly materials to avoid the pollution caused by the Portland cement industry. Geopolymer is a developed industrial by-product-based alternative concrete binder. The aim of this study to evaluate the effect of different proportions of Fly Ash (FA) and Ground Granulated Blast Furnace Slag (GGBFS) on the strength properties of geopolymer mortar. In this study, GGBFS was added as 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 100% of the total binder with NaOH concentrations 12 M and sodium silicate to sodium hydroxide ratio 2.5. The compressive strength was investigated experimentally in this study. The combination of FA and GGBFS were tested in a total of eleven geopolymer mix mortars, and the results show that combining the above constituents at 70℃ improves the compressive strength of geopolymer mortar. The result show that the mixture with 100% GGBFS replacement have maximum compressive strength (78.25 MPa) at 7-days age.

EFFECTS OF CHEMICAL ADMIXTURES FOR CEMENT CONCRETE ON MORTAR FLOW AND COMPRESSIVE STRENGTH OF GEOPOLYMER

Huge amounts of Portland cement which is a main constituent material of concrete is manufactured and carbon dioxide (CO2) emitted by the manufacturing process of cement can cause global warming. Geopolymer (GP) contains no cement as a binder and several industrial by-products such as fly ash and blast furnace slag, so the spread of GP contributes to the reduction of global warming and the environmental load. GP has low CO2 emissions, high durability due to chemical attack and fire resistance, however, viscosity of GP is higher than that of cement concrete. Although chemical admixtures can be effective to the improvement of workability, most commercial products of them are for cement concrete. In this study, mortar flow and compressive strength of GP were experimentally evaluated in order to investigate effects of several chemical admixtures for cement concrete. Water glass and caustic soda solution were used as an alkaline-activating solution, and water glass causes high viscosity of GP mortar, so mortar flow test and compression test were conducted by using GP mortar with and without water glass. Test results indicate that the GP mortar without water glass had lower viscosity and lower compressive strength than that with water glass. The chemical admixture whose base component is naphthalenesulfonic acid was most effective to fluidity and compressive strength of GP mortar without water glass.