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This study investigated the compression molding of hybrid composite materials using waste concrete powder (WCP) and bagasse fiber (BF) as a novel reuse procedure for waste concrete. The matrix of the composite material was applied to powder-type polyethylene (PE) to facilitate the compression molding of the gas vent. The WCP was obtained by milling siliceous waste concrete using a pot mill procedure. The main constituent of the WCP was quartz. The flexural strength and modulus of the hybrid composite material, in which BF was added to mix the powder with PE and WCP, increased with increasing BF content and exhibited a maximum value at a BF content of 30 wt. %. Next, to improve the mechanical properties of the hybrid composite material, we attempted to improve the adhesiveness between PE and BF by increasing the molding temperature. The mechanical properties of the hybrid composite material with a BF content of 40 wt. % exhibited the highest values at a molding temperature of 413 K. Furthermore, by increasing the WCP content in the hybrid composite material with a BF content of 40 wt. %, the flexural strength exhibited the maximum value at a WCP content of 20 wt. %. Therefore, it was revealed that the composite material using PE powder and WCP could be strengthened by adding BF.

This paper aims to fabricate a composite material using calcareous waste concrete powder and coal fly ash (FA) by spark plasma sintering. The effect of FA addition on the mechanical properties of the composite material were investigated. The maximum FA content was 7.5 wt%. The relative density of the composite material was approximately 1.0, independent of FA content. In contrast, the Vickers hardness, flexural strength, and flexural modulus increased with increasing FA content. However, the dispersion state of FA in the composite material was not observed by scanning electron microscopy. Powder X-ray diffraction of the composite material revealed that spurrite and wollastonite were formed identically, independent of FA content. Therefore, FA serves as a reinforcement in the composite material. [ABSTRACT FROM AUTHOR]

This study investigated the conditions for zeolite synthesis from waste concrete powder (WCP) using the hydrothermal synthesis method. The WCP was prepared by milling the waste concrete using pot mill equipment. The synthesis conditions, i.e., the heating time, heating temperature, and NaOH solution concentration were varied. Furthermore, hydrochloric acid-treated WCP (WCP-HCl), which is removed the calcium component, was prepared to examine the effectiveness of acid treatment in the zeolite synthesis. The zeolite synthesis was investigated using X ray diffraction (XRD) and scanning electron microscopy (SEM). Analcime-type zeolite was synthesized using WCP and WCP-HCl. The requirements of synthesis conditions for analcime were as follows: heating time above 12 h, heating temperature above 433 K, and NaOH solution concentration above 2 mol/ L. With a progressive increase in the concentration of the NaOH solution from 5 to 7 mol/L, analcime could be synthesized at NaOH concentrations below 4 mol/L, while cancrinite was synthesized at NaOH concentrations exceeding 5 mol/L. The peak intensity of analcime and cancrinite of WCP-HCl showed high value in comparison to the WCP. Thus, the effectiveness of the HCl treatment of WCP was confirmed from the XRD patterns. [ABSTRACT FROM AUTHOR]