Title:
Developing Eco-friendly Concrete with Sustainable Supply: The Potential of Using Whole Recycled Gypsum Drywall
Author(s):
Alireza Jafari
Publication:
Web Session
Volume:
ws_S25_AlirezaJafari.pdf
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
3/30/2025
Abstract:
Fly ash is the most common cement alternative used to reduce demand for cement in cementitious composites and, thereby, their environmental impacts. Studies show that incorporating up to 10% fine recycled gypsum drywall (RGD) in high-volume fly ash concrete (HVFA) maintains mechanical strength while reducing cement demand. However, using only fine RGD returns almost 70% of the RGD into landfills, causing ecosystem contamination. This study examines incorporating whole RGD in high-volume fly ash concrete with 40% (F40) and 50% (F50) fly ash by testing 36 concrete cylinders for mechanical strength, unit weight, and porosity at 7, 28, and 90 days. The data revealed that replacing fine RGD with the whole RGD increased the 7-day by 11 and 10% in the F40 and F50, respectively. However, the strength of specimens containing fine RGD surpassed those containing whole RGD by 1 (in F40) and 4.4% (in F50) at 90 days, respectively. Comparing F50 and F40 specimens with 10% RGD, the 7-day strength of specimens decreased by 35.1 (whole RGD) and 41.98% (fine RGD) compared to F50. However, the superior strength improvement of the RGD narrowed the difference to less than 8%. The data also suggested that adding RGD could increase the porosity of the concrete, identified by a reduction in ultrasonic pulse velocity and unit weight. Accordingly, while the study showed the potential of whole RGD, findings proposed the whole RGD as an efficient alternative for fly ash in HVFA, especially critical given environmental regulations limiting biomass combustion and fly ash availability.