• Computers and Concrete
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• v.14 no.5
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• pp.577-597
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• 2014

This paper aims to develop a prediction model for the hardened properties of waste LCD glass that is used in concrete by analyzing a series of laboratory test results, which were obtained in our previous study. We also summarized the testing results of the hardened properties of a variety of waste LCD glass concretes and discussed the effect of factors such as the water-binder ratio (w/b), waste glass content (G) and age (t) on the concrete compressive strength, flexural strength and ultrasonic pulse velocity. This study also applied a hyperbolic function, an exponential function and a power function in a non-linear regression analysis of multiple variables and established the prediction model that could consider the effect of the water-binder ratio (w/b), waste glass content (G) and age (t) on the concrete compressive strength, flexural strength and ultrasonic pulse velocity. Compared with the testing results, the statistical analysis shows that the coefficient of determination $R^2$ and the mean absolute percentage error (MAPE) were 0.93-0.96 and 5.4-8.4% for the compressive strength, 0.83-0.89 and 8.9-12.2% for the flexural strength and 0.87-0.89 and 1.8-2.2% for the ultrasonic pulse velocity, respectively. The proposed models are highly accurate in predicting the compressive strength, flexural strength and ultrasonic pulse velocity of waste LCD glass concrete. However, with other ranges of mixture parameters, the predicted models must be further studied.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.11a
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• pp.67-69
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• 2012

This paper is to investigate the effect of waste oil on the fundamental properties of high volume fly ash concrete depending on W/B and waste oil contents. Test results reveals that the use of waste oil resulted in an increase of slump and a decrease of air contents due to the presence of emulsion in waste oil. And it is found that the addition of waste oil does not affect the strength development of the concrete significantly.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.245-250
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• 2001

Ultrasonic pulse velocity(UPV) is a useful tool for examining the property of early-age mortar or concrete. Thus, UPV has been used for a long time to characterize setting and hardening of cementitious materials. In this study, in order to investigate the characteristics of setting for mortar, UPV was measured using automatic monitoring system up to 3 days after casting. Test results show that UPV of high water to binder ratio(w/b) mortar remained constant at the beginning of hydration and then abruptly began to increase. However, UPV of low w/b mortar gradually increase due to setting retard caused by use of superplasticizer. Furthermore, the development of UPV for mortar with fly ash is slower than that of mortar without fly ash. It was concluded that the property change of mortar or concrete, such as setting and hardening can be assessed by monitoring of UPV.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.199-200
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• 2023

This paper presents a study on the selection of optimal mix proportions for producing lightweight pre-foam concrete as a substitute for Autoclaved Lightweight Concrete (ALC) without the accelerated curing. The study was conducted using a rapid hardening binder made from by-products of the steel industry as the primary raw material. The experimental results established the optimal mix proportions, which included retarder content, water/binder ratio, foam content, and fiber inclusion amount, for the production of lightweight foam concrete. The optimal mix proportion was determined to have a retarder content at the minimum amount required to secure the working time, W/B of 35%, a foam content limited to 65% or less, and a fiber inclusion amount of 0.05% or less.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.357-364
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• 2017

In this paper, we investigated the influence of flow and compressive strength on the mixing ratio and water-to-binder (W/B) ratio of magnesia - potassium phosphate composites for controlling the quality of the Magnesia-Potassium Phosphate Composites(Magnesia-Potassium Phosphate Composites, MPPC) as a matrix material for biological panels. MPPC was produced at 7 W/B ratios (30, 35, 40, 45, 50, 55 and 60 vol.%) and 4 P:M ratios (1:0.5, 1:1.0, 1:2.0 and 1:3.0). The experiment results confirmed that the flow and compressive strength of MPPC depend strongly on both P:M and W/B ratios. The flow of MPPC showed that as P: M was increased, the mixing did not occur due to the shortage of the compounding amount for the reaction, because of the large density difference between P and M. The compressive strength of MPPC showed a tendency to decrease with increasing P:Mratio but there was a contradictory result with no proportional change according to W/B ratio. These results indicate that the optimum compounding ratio exists for MPPC according to W/B ratio. These results will be used as the basis data for quality control of the fluidity and compressive strength of matrix materials in terms of material in biological panel design.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.89-92
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• 2006

To investigate the properties of high flowing and high strength concrete with crushed sand and fly ash for CFT structure, many batches were performed by a trial-error method. In the experiment W/B was set up three levels as 0.25, 0.30 and 0.35. Also the variables of the experiment were a substitution ratio of fly ash, a blend ratio of crushed sand and the ages of specimens(3, 7, 28 days). The results of this study are summarized as the follows; 1) The effect a substitution ratio of fly ash on the compressive strength was not consistent with age. For twenty-eight day compressive strength, the best result was come out when cement was substituted by 10% of fly ash. 2) The decrease of the water binder ratio, the increase of compressive strength and elastic modulus. Also the relationship is very similar to the case of a normal concrete

• Journal of the Korea Institute of Building Construction
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• v.11 no.6
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• pp.538-546
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• 2011

This paper is to experimentally investigate the strength and autogenous shrinkage of high strength mortar with the 20 % of water?binder ratio(W/B). In this study, the water substituting liquid(WSL) was used including gasoline, light oil, lamp oil, edible oil, HFE, ethanol, methanol and acetone in order to explore changes in strength and autogenous shrinkage depending on WSL type and replacement. For fresh properties, the replacement of WSL did not affect the fluidity of mortar mixtures considerably, except for ethanol and methanol. However, the replacement of WSL resulted in a slight decrease in flexural and compressive strength. For autogenous shrinkage, the replacement of WSL led to reduce autogenous shrinkage, and especially, the replacement of edible oil led to reduce autogenous shrinkage significantly due to saponification between edible oil and cement.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2014.05a
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• pp.270-271
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• 2014

In this study, a replacement ratio of blast furnace slag coarse aggregate and a water binder ratio by an optimum combination of PHC file was investigated. As a results, the target strength 78.5MPa was altogether satisfied in a mix proportion 28-G100-SG0 and W/B ratio 26 %. The surface rupture was generated in 28-G0-SG100 combination after curing with the autoclave. According to the result of measuring the ingredient, the majority were the MgOH2 hydrate.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.11a
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• pp.83-86
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• 2007

This study provides the practical application of the concrete using fiber to protect from fire studied by previous research. The fluidity and air content is satisfied with the targets, and the compressive strength is over 60MPa on W/B 35% and 80MPa on W/B 20 and 25%. For the properties of the spalling after the fire test, there is no spalling or slight occurrence on the specimens. However, for the RC column, the covering concrete fall off caused by spalling occurrence. Based on the results, it is thought that the fiber content should be put into the safety factor to prevent spalling for the structures.

• Computers and Concrete
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• v.25 no.2
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• pp.119-132
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• 2020

There is a growing interest in the use of by-product materials such as ceramics as alternative materials in construction. The aim of this study is to investigate the mechanical properties and durability of sustainable concrete containing waste ceramic powder (WCP), and to predict the results using artificial neural network (ANN). In this order, different water to binder (W/B) ratios of 0.3, 0.4, and 0.5 were considered, and in each W/B ratio, a percentage of cement (between 5-50%) was replaced with WCP. Compressive and tensile strengths, water absorption, electrical resistivity and rapid chloride permeability (RCP) of the concrete specimens having WCP were evaluated by related experimental tests. The results showed that by replacing 20% of the cement by WCP, the concrete achieves compressive and tensile strengths, more than 95% of those of the control concrete, in the long term. This percentage increases with decreasing W/B ratio. In general, by increasing the percentage of WCP replacement, all durability parameters are significantly improved. In order to validate and suggest a suitable tool for predicting the characteristics of the concrete, ANN model along with various multivariate regression methods were applied. The comparison of the proposed ANN with the regression methods indicates good accuracy of the developed ANN in predicting the mechanical properties and durability of this type of concrete. According to the results, the accuracy of ANN model for estimating the durability parameters did not significantly follow the number of hidden nodes.