A FEASIBILITY STUDY ON A BIOCHAR-POLYETHYLENE TEREPHTHALATE CEMENTITIOUS COATING AS A WATERPROOFING COATING

Abstract

The incorporation of both biochar and polyethylene terephthalate (PET) has not been investigated by many researchers. This research explores the filler-effect, water retention capability, internal curing benefits of biochar, as well as the durable and hydrophobic sustainable PET. Raw mixed wood biochar was received from the forest industry in Thailand that was pyrolysed between 300°C up to 400°C. PET was obtained from manual processing of post-consumed plastic bottles. The effects of coatings with biochar-PET as partial replacement of aggregate were evaluated on their ability to improve contact angle of the formulated coatings, enhance adhesive strength to substrate, and reduce water capillary actions by means of reducing water absorption. CA test has suggested that the incorporation of PET at 5% cement weight (8.33% as partial replacement of aggregates) and 2% weight of cement have improved the hydrophilic nature of coatings to exhibit signs of hydrophobicity. Water absorption test has shown promising improvement in coating incorporated with PET and 2% biochar. However, pull-off test results were not conclusive of the intrinsic adhesive strength of coatings due to the nature of fracture, thus attention can be diverted into the coating composition and thickness. These results have carved the path for potential biochar-PET to be deployed into cementitious coating for future waterproofing application.