document: An innovative sound wall system was developed in the University of Western Ontario, and was examined to serve as a vertical extension to the existing sound walls. The wall system (denoted as flexi-wall) consists of stay-in-place poly-blocks as formwork, light polyurethane foam (LPF) reinforced with steel rebars as structural cores and polyurea as a coating of the wall surfaces (Fig. 1). Poly-blocks are interlocking light-weight blocks which are stacked up layer by layer and act as formwork for the LPF cores. The poly-block is 20×20×80cm3 and includes four cylindrical voids with 14cm diameter. It is made of molded low-density polyurethane and weighs approximately 1kg. The poly-blocks are fire-resistant blocks and have an excellent capability to absorb, mitigate and reflect a wide range of noises with unmatched frequency of reflective noise. Polyurea coating is an abrasion-resistant finishing layer, which is sprayed on the surfaces of the wall and sets within 2–3min. This layer also enhances the surface resistance of poly-blocks against stone impact, weathering, fire development, chemicals and penetration. LPF is an expanding liquid mixture which is injected into the poly-block voids and cures within 10min. Steel rebars are epoxied into holes drilled in the existing sound wall to connect the wall extension to its base.
doc_bio_tags: O O B I I O O O O O O O O O O O O O O O O O O O B I I O B I O O O O O O O O O B I I B O O B I O B I O B O O B O O B I O O O O O O O O O O O B O B O O O O O O B O O O O O O O O B I O O O O O O O O O O O O O O O O O O O O O O O O O B B O B O O O O O O O O O O O B B O O O O B O O B O O B I I I O O O O O B O B I I I O O O B I B B I B O B B O O B I I O O O O O O O O B O O B I O O O B O O O B I I O O O B I O O B
extractive_keyphrases: absorb base chemicals coating cures cylindrical voids enhances the surface resistance existing sound wall existing sound walls expanding liquid mixture fire development holes layer light polyurethane foam lpf mitigate penetration polyurea reflect sound wall system sprayed steel rebars stone impact structural cores surfaces of the wall wall extension wall surfaces wall system weathering
abstractive_keyphrases: abrasion-resistant finishing layer fire-resistant blocks flexi-wall interlocking light-weight blocks lpf cores molded low-density polyurethane poly-block poly-blocks poly-block voids polyurea coating stay-in-place poly-blocks