• Resources Recycling
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• v.12 no.5
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• pp.23-28
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• 2003

Converter slag was reduced and modified with the addition of 5~10 weight percent of $SiO_2$, $Al_2O_3$ and $SiO_2+Al_2O_3$. which was water quenched and used as a cement additives. Additive was mixed from 10 to 30 weight percent with ordinary portland cement and made 9 kinds of mixed cement. Compressive strength of mixed cement mortar was tested md compared with com pressive strength of ordinary portland cement mortar. Effect of hydration reaction on the compressive strength of cement mortar was investigated by means of x-ray diffraction and scanning electron microscopy.

• Journal of environmental and Sanitary engineering
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• v.14 no.3
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• pp.22-30
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• 1999

This study was carried out to examine the compressive strength characteristics of solids solidified with the lead sludge with mixture of cement and fly ashes as additive. And the additives are commercial fly ash and ESP(Electrostatic precipitator) fly ash. The compressive strength of solidified lead sludge solid was increased by adding fly ash up to 46~62%, which was the results of pozzolanic reaction. When replaced the cement with 10%of commercial fly ash, the solid showed the highest value $210{\;}kg/cm^2$, and the solidification conditions were 0.55 of the water/cement ratio and curing for 14 days. Also, the results of leaching test by EPT(Environmental Protection Agency-Toxicity Test) were showed that the solidified lead has leached out under 10%, which was less than 0.173 mg/L of EPA standard. As leaching solutions, the demineralized water, 0.1N acetic acid solution, and synthetic brine were used. and the observations by SEM of the solidified lead-laden solid after EPT leaching test were indicated the severe erosion on solid surface.

• Journal of the Korean Ceramic Society
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• v.36 no.7
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• pp.685-690
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• 1999

Modified belite cement clinker containing $\alpha$'-C2S and C4A3 were syntehsized form the mixture of raw materials. $\alpha$'-C2S was stabilized at room temperature by adding borax. Properties of the clinker were charaterized with a XRD, SEM, TEM The additive effects of slag on the hydration properties were also estimated by measurement of compressive strength fluidity and heat evolution. The experimental results exhibited that the addition of slag to the belite cement improves the fluidity and early compressive strength due to the formation of ettringite and C-S-H. The compressive strengths of the mortar with 20% slag after 7, 90 days hydration were 212, 355 kgf/cm2 respectively.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.151-152
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• 2020

When concrete is exposed to fire, the thermal decomposition of hydrates of Portland cement paste results in critical damage to the concrete structure of a building. Recently, nanosilica arose as the effective nano-additive which can enhance the thermal resistance of the cementitious materials. However, the mechanism of the enhancement was not elucidated specifically. In this study, we investigated the properties of calcium silicate hydrates(C-S-H)of the nanosilica incorporated cement paste after heating to different heating temperatures (200℃, 500℃, and 800℃) by 29Si nuclear magnetic resonance. The results showed that the polymerization of C-S-H of nanosilica incorporated samples was larger than ordinary cement paste after heating to 200℃, and C-S-H formed during heating process to 500℃ due to the pozzolanic reaction during heating process.

• Advances in concrete construction
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• v.17 no.4
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• pp.211-220
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• 2024

Concrete, consisting mainly of cement, water and aggregates; is the most used construction material all over the world. Cement manufacturing industry is one of the carbon dioxide producing sources that contributes to global warming. Therefore, in the last few years, there is a growing interest in using waste materials and by-products as cement replacement materials. Using these kinds of materials as a part of cement replacement reduces the air pollution, cost and also enhances some properties of concretes. In the present work, marble dust (MD) was examined as a partial cement replacement material with seven proportions as 0%, 10%, 20%, 30%, 40%, 50%, 60% and glass powder (GP) was used as an additive, 8% by cement weight, in a 0.55 water-binder ratio concrete. In order to evaluate their effects; workability, strength (compressive, flexural and split tensile), alkalinity, sulphate resistance and ultrasonic pulse velocity tests were performed. Experimental results indicated that with MD replacement and GP addition; there is a loss in the workability but improvement in mechanical properties. With 10% replacement of MD compressive, flexural and tensile strengths increased by 10.7%, 6.2% and 5.3% respectively. Moreover, up to 30% replacement of MD reasonable strength values were obtained.

• International Journal of Highway Engineering
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• v.19 no.2
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• pp.137-142
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• 2017

PURPOSES :The objective of this study is to evaluate the performance of asphalt mixtures containing inorganic additive and a high content of reclaimed asphalt pavement (RAP). METHODS : The laboratory tests verified the superior laboratory performance of inorganic additive compared to cement, in cold recycled asphalt mixtures. To investigate the moisture susceptibility of the specimens, tensile strength ratio (TSR) tests were performed. In addition, dynamic modulus test was conducted to evaluate the performance of cold recycled asphalt mixture. RESULTS :It was determined that NaOH solution mixed with $Na_2SiO_3$ in the ratio 75:10 provides optimum performance. Compared to Type B and C counterparts, Type A mixtures consisting of an inorganic additive performed better in the Indirect tensile strength test, tensile strength ratio test, and dynamic modulus test. CONCLUSIONS : The use of inorganic additive enhances the indirect strength and dynamic modulus performance of the asphalt mixture. However, additional experiments are to be conducted to improve the reliability of the result with respect to the effect of inorganic additive.

• Environmental Engineering Research
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• v.23 no.2
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• pp.189-194
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• 2018

The traditional gold mining in Kulon Progo district, Special Region of Yogyakarta Province produced tailings containing mercury (Hg) from the gold amalgamation process. Mercury accumulated in tailings has 164.19 mg/kg - 383.21 mg/kg in total concentration. Stabilization/solidification (S/S) is one of the remediation technologies to reduce waste pollution. Portland cement is one of the additive materials in S/S that effective encapsulates heavy metal waste. The aim of this research is to know the optimum composition of tailings mixture with Portland cement in S/S process. This research used variation of tailings composition. Variation of Portland cement composition with tailing are 100:0, 90:10, 80:20, 70:30, 60:40, 50:50, 40:60, 30:70, 20:80 and 10:90. The result of this study found that the optimum composition of Portland cement: tailings was 10:90, with compression test of $257ton/m^2$ and TCLP test was 0.0069 mg/L. The compression test results were in accordance to US EPA Standard quality of $35ton/m^2$. TCLP test results meet the standard of Indonesian Government Regulation No. 101 Year 2014 of 0.05 mg/L.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.11a
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• pp.172-173
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• 2021

With the development of nano-reinforcement technology and the increasing concern for environmental issues, TiO₂ nanomaterials have received wide attention as an additive besides carbon nanomaterials that can be used to enhance the mechanical properties of cement-based materials. Also, TiO₂-based materials can allow cement-baned materials with photocatalytic capability, providing a potentially effective approach to reduce environmental problems. In this work, compressive strength, splitting tensile strength, and degradation of methylene blue solution were used as target to assess the effect of TiO₂ nanotubes on the mechanical strength and photocatalytic effect of hardened cement paste at different curing time. According to the strength results, the optimum amount of TiO₂ was identified as 0.5% of the weight of cement. Meanwhile, the TiO₂ nanotubes-reinforced specimen exhibited better photocatalytic effect in the early stage of curing.

• Proceedings of the IEEK Conference
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• 2001.10a
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• pp.508-513
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• 2001

Recently, ground granulated blast-furnace slag (GGBFS) has been increasingly used as additive for concrete. Many researchers reported that concrete using GGBFS had a better resistance under severe environments, such as marine or sulfate-rich soils, than Portland type cement concrete. The aim, therefore, of this study is to evaluate on the effectiveness of concrete using GGBFS when the concrete exposes to sulfate-rich environment. The detailed items for experiments show 2 series consisted of sulfate immersion test with mortar and sulfate diffusion test with concrete. The sulfate immersion test was performed for 400 days and contained reduction of compressive strength, length change and XRD analysis. For sulfate diffusion test, sulfate ions diffusivity was calculated on tile consideration of electrochemical theory by the diffusion cell test. As the results of this study, it was found that the concrete using GGBFS as additive was superior to portland type cement concrete. Consequently, the use of concrete with GGBFS for recycling may expect the durable and economical benefits.

• International Journal of Highway Engineering
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• v.20 no.1
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• pp.27-33
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• 2018

PURPOSES : The purpose of this study is to estimate the optimum content of an inorganic additive for cold-recycled asphalt mixtures and evaluate its performance. METHODS : An indirect tensile test, a tensile-strength ratio test, and an indirect tensile-fatigue test were conducted on cold-recycling asphalt mixtures with various additives. RESULTS : The laboratory performance tests indicated that granulated blast-furnace slag mixed with inorganic and cement activators provided optimum performance. The performance results of the cold-recycled asphalt pavement were similar to the inorganic and cement activators' performance in terms of the indirect tensile strength, tensile strength ratio, and indirect tensile-fatigue test. CONCLUSIONS : Overall, the performance of a cold-recycled asphalt mixture using inorganic additives and emulsion asphalt was comparable to a warm-recycled asphalt mixture. However, more experiments aimed at improving its performance and studying the effect of the inorganic additives must be conducted.