The purpose of this study was to investigate the best ratio of waste foundry sand (WFS), fly ash (FA), and electric arc furnace slag (EAF slag) for the production of geopolymer bricks. In this research study, WFS, FA, and EAF slag were mixed at the ratio of 70:30:0, 60:30:10, 50:30:20, and 40:30:30 with 8M sodium hydroxide (NaOH) and 98% purity sodium silicate (Na 2 SiO 3 ) with a ratio of Na 2 SiO 3 /8M NaOH ¼ 2.5. The mixtures were compacted in 5 cm  5 cm x 5 cm molds and cured at an ambient temperature for 28 days. Then, their compressive strength was analyzed. The results showed that the geopolymer bricks with the highest compressive strength were those mixed at the 40:30:30 ratio, with a compressive strength of 25.76 MPa. The strongest bricks were also analyzed using the leaching test to ensure the production involved non-hazardous materials. To compare the environmental impacts of geopolymer bricks and concrete bricks, their effects on climate change, ozone depletion, terrestrial acidification, human toxicity, terrestrial ecotoxicity, and fossil fuel depletion were examined from cradle to grave using SimaPro 8.0.5.13 software. The results of the life cycle assessment (LCA) from cradle to grave showed that the environmental impact of geopolymer brick production was lower in every aspect than that of concrete production. Therefore, geopolymer brick production can reduce environmental impact and can be a value-added use for industrial waste.

The objective of this research is to manage waste glass in Koh Sichang, Chonburi province, used as a partial fine aggregate replacement in concrete brick production. An experimental approach aimed to determine the level of waste glass replacement for the optimal compressive strength. Five samples of 0, 10, 20, 30, and 100% waste glass aggregates by weight were tested at 7, 14, and 28 days. The microstructure and mineralogical phases of the concrete bricks were investigated by scanning electron microscopy and X-ray diffractometry, respectively. The experimental results showed that the compressive strength was improved by increments in replacing waste glass up to 20%; in contrast, the compressive strength was decreased with an increase of waste glass of over 20% in concrete bricks. The optimum compressive strength of concrete brick was 20% by weight, which had the highest values (46.51, 47.41, and 48.49 MPa at 7,14, and 28 days, respectively) and the lowest water absorption. Therefore, waste glass can be used as a partial fine aggregate for producing concrete bricks, and it can be employed as an alternative material for waste glass management.

This research investigated pyrolysis as a potential method to manage plastic waste in Sichang Island, Thailand. Pyrolysis was chosen to convert waste plastic into fuel oil using Al–Si catalysts derived from cogon grass. The study consisted of three stages. The first stage determined the composition of the waste plastics found in Sichang Island. High-density polyethylene (48%) comprised the highest proportion of the waste plastics, followed by low-density polyethylene (22%), polyethylene terephthalate (13%), polypropylene (10%), and polystyrene (7%). In the second stage, the Al–Si catalysts were prepared from cogon grass ( Imperata cylindrica (L.) Beauv) by treating it with acid and calcination. The optimum conditions to extract silica from cogon grass through acid treatment were heating at 700 °C for 2 h, which yielded 97.7% of amorphous silica with a surface area of 172 m 2 /g and a pore volume of 0.43 cc/g. This amorphous silica was combined with an aluminum precursor to form Al–Si catalysts with 20–80 wt% of Al–Si. The results showed that the surface area of the catalyst increased with increasing aluminum content. The optimum ratio was 60 wt% of Al–Si with a surface area of 200 m 2 /g. In the final stage, the catalytic properties of the previously prepared Al–Si catalysts in the pyrolysis of waste plastics were evaluated. The catalyst enhanced the plastic cracking process and the oil yield while decreasing the reaction time. The optimum ratio of 60% Al–Si to 10% waste plastic provided the maximum oil yield of 93.11% and the minimum reaction time of 20 min. The results showed that catalytic cracking with 60% Al–Si contributed to a high quantity of oil yield, similar to using a commercial Al–Si catalyst. The results of this research will be applied as an alternative method of recycling plastic for sustainable waste management in Sichang Island.

The purpose of this study was to investigate the ratio of concrete residue (CR) and electric arc furnace slag (EAF) for the production of facing brick according to Thai Industrial Standard (TIS) 168-2546. These two industrial wastes contain high alumina and silica for the production of geopolymer bricks. In this research, CR and EAF were collected and homogenously mixed at the following CR to EAF ratios: 100:0, 90:10, 80:20, 70:30, and 60:40, with sodium hydroxide (10M NaOH) and sodium silicate (Na2SiO3) solutions as catalysts. The ratio of Na2SiO3 to 10M NaOH was 2.5. The mixtures were poured in molds (5 cm x 5 cm x 5 cm) and cured in plastic film at room temperature for 28 days. Then the mechanical and chemical properties of the brick specimens were analyzed, including dimensions and tolerances, wryness, deviation from right angles, water absorption, compressive strength, stains, holes, rails, and cracks, according to TIS 168-2546. The results showed that the optimum CR to EAF ratio of geopolymer bricks that was compliant to the TIS 168-2546 standard was 80:20, which had the highest compressive strength value (17.04 MPa) and the lowest water absorption (0.69%). Therefore, CR and EAF can be used as raw materials for facing bricks production.