Her-Yung Wang

A study of the effects of LCD glass sand on the properties of concrete

In order to study the recycling of discarded liquid crystal display (LCD) glass into concrete (LCDGC), a portion of the usual river sand was replaced by sand prepared from discarded LCD glass. Three different mix designs were regulated by the ACI method (fc(28)=21, 28, and 35MPa) with 0%, 20%, 40%, 60%, and 80% LCD glass sand replacements investigated; their engineering properties were determined. Test results revealed that, when compared to the design slump of 15cm, the 20% glass sand concrete for the three different mix designs kept good slump and slump flow. Furthermore, a slump loss ranging from 7 to 11cm was observed for specimens with 60% and 80% glass sand replacement for the design strengths of 28 and 35MPa. The compressive strengths of the concrete with glass sand replacement were higher than the design strengths. Moreover, the durability of the concrete with 20% glass sand replacement was better than that of the control group. Surface resistivity for specimens with different amounts of LCD glass sand replacement was also higher than that in the control group for mid to long curing ages. The sulfate attack in concrete with different amounts of glass sand replacement caused less weight loss than in the control group. Moderate chloride ion penetration was observed for glass sand concrete. Furthermore, the measured ultrasonic pulse velocities for LCD glass sand concrete specimens were higher than 4100m/s, which qualified these specimens as good concrete. OM and SEM indicate that the dense C-S-H gel hydrate was produced at the interface between the glass sand and cement paste. The test results indicate that the addition of 20% LCD glass sand to concrete satisfies the slump requirements and improves the strength and durability of concrete. This suggests that LCD glass sand can potentially be used as a recycled material in concrete applications.

Mix proportions and properties of CLSC made from thin film transition liquid crystal display optical waste glass

In this study, controlled low-strength concrete (CLSC) is mixed using different water-to-binder (W/B) ratios (1.1, 1.3 and 1.5) and various percentages of sand substituted by waste LCD glass sand (0%, 10%, 20% and 30%). The properties of the fresh concrete, including compressive strength, electrical resistivity, ultrasonic pulse velocity, permeability ratio and shrinking of the CLSC, are examined. Results show that increases in amount of waste glass added result in better slump and slump flow, longer initial setting time and smaller unit weight. Compressive strength decreases with increasing W/B ratio and greater amounts of waste glass added. Both electrical resistivity and ultrasonic pulse velocity increase with increases in amount of waste glass and decreases in W/B ratio. On the contrary, the permeability ratio increases with increases in W/B ratio, but decreases with greater amounts of waste glass added. CLSC specimens cured for different durations show little changes in length with shrinkage below 0.025%. Our findings reveal that CLSC mixed using waste LCD glass in place of sand can meet design requirements. Recycling of waste LCD glass not only offers an economical substitute for aggregates, but also an ecological alternative for waste management.

Analytical Model of Ultrasonic Pulse Velocity of Waste LCD Glass Concrete

The purpose of this study is to establish a prediction model for the ultrasonic pulse velocity (UPV) of waste LCD glass concrete and then analyze the results obtained from a series of laboratory tests. The power function is used to perform the nonlinear-multivariate regression analysis of the UPV prediction model, with parameters such as water-binder ratio (w/b), curing age (t) and waste glass content (G). According to the relative regression analysis, the UPV prediction model is developed. The calculated results are in accord with the laboratory- measured data, which are the concrete UPV of various mix proportions. The regression analysis results show that a good agreement is obtained using the proposed prediction model. Therefore, the predicted results for UPV are highly accurate for waste LCD glass applied in concrete. Additionally, the proposed prediction model exhibits a good predictive capacity when it is adapted to calculate the UPV of high-performance recycled liquid crystal glass concrete (HPGC), as performed in a previous study. However, further study is needed as regards applying the proposed prediction model to other ranges of mixture parameters.

Characteristics of Compressed Concrete Paving Units Produced from Washed Municipal Solid Waste Incinerator Bottom Ash

This study replaced natural aggregate with a fine aggregate of washed municipal solid waste incinerator bottom ash (WMSWIBA) in the production of compressed concrete paving units to increase the applications of WMSWIBA. The cement-aggregate ratios investigated were 0.1, 0.2, 0.3, 0.4 and 0.5, and the water-cement ratios were 0.20, 0.25 and 0.30. The results showed that the coefficient of permeability of the compressed concrete paving units was less than 2.66×10-5 cm/sec, the water absorption was 13.55~4.75%, the porosity was 8.05~1.62%, the compressive strength was 12.3~48.5 MPa, the ultrasonic pulse velocity was 1521~3059 m/sec, and the attrition volume loss was 117.7~16.0 cm3/50 cm2. The results suggested that the compressive strength and ultrasonic pulse velocity increase with the cement-aggregate ratio, whereas the attrition loss decreases.

A Nonlinear-Multivariate Regression Prediction of Compressive Strength of Waste Glass Concrete

In this study, a predictive model on compressive strength of waste LCD glass concrete was developed by analyzing a series of laboratory test results. The compressive strength prediction model with parameters of the water-binder ratio w/b, curing age t, and waste glass content G was progressed by nonlinear-multivariate regression analysis. The calculated results are appropriate with the laboratory measured data. In addition, the coefficient of determination R2 value is 0.93–0.96, were obtained by regression analysis using the model predicted compressive analysis value and test result are also excellent.

Applying value engineering to evaluate the use of concrete in an underground railway construction project

The object of this research is an underground railway construction project. The railway will be 8.23 kilometers long with three stations located along it. The project will cost totally NT

A Study of Engineering Properties of Concrete Containing Recycled Materials in Hot Spring Environment

29.36 billion and take seven years and eight month to complete. The total amount of concrete used in this project is estimated to be as large as 56,900 cubic meters. By using the value engineering technology, this study evaluated totally five concrete alternatives for the construction project. According to the findings of this research, self-compacting concrete (SCC) is the best alternative for it can help to save nearly NT

A Study on Engineering Properties of Self-Compacting Concrete Containing Waste LCD Glass

80 million, that is 24.8% of the original budget of NT

Feasibility Study of Using Desulphurization Slag as Binder Material for Concrete Mixing

352 million for concrete. The amount of cement required for the project is half the amount of regular concrete project. In addition to cutting costs, SCC is more environmentally friendly for it uses industrial wastes as its ingredients. It is known as the green concrete for it is helpful in reducing carbon emissions and, hence, mitigating the greenhouse effects. The findings and suggestions of this study were sent to the authorities in charge of the project and have been accepted and adopted by the engineering consultants in the underground railway construction.

Effect of Autoclave Curing on the Compressive Strength and Elastic Modulus of Lightweight Aggregate Concrete

Taiwan is gifted with special geothermal resources, such as hot springs. In recent years, due to rapid development of the hot spring tourism and medical industry, massive constructions at the side slopes in hot spring areas are requiring the large amount of concrete material. Thus, the engineering properties of concrete material in the hot spring environment are an important research subject. Taiwan yields a large output of fly ash, slag and waste LCD glass annually. If these recycled materials can be added into concrete materials as mineral admixture, the construction quality will be improved, while contributing to waste reduction. Therefore, this study used the concrete without and with different recycled materials (e.g., slag, fly ash and glass waste powder) respectively to make specimens in fixed water-binder ratio W/B=0.44, and tested the compressive strength, splitting strength, ultrasonic pulse velocity and rate of volume change in general water curing and hot spring water curing conditions. The results showed that the strength deterioration and volume expansion of the concrete with recycled materials could be postponed in the hot spring water environment, and the glass waste powder had the best effect.