Browsing by Author "Jaakola, Suvi"

Plastics are important materials in construction due to their longevity, durability and lightness. However, the use of plastics should be reduced as they are made mainly from fossil fuels and unnecessarily end up in the environment where they cause damage to various organisms. The purpose of this Master's thesis was to investigate whether the plastics currently used in infrastructure construction can be replaced by better choices in terms of recyclability and carbon footprint. The subject of the thesis was two infrastructure construction sites in the city of Helsinki, where it was studied how much and what types of plastics were purchased for the site, excluding packaging plastics. Thereafter, circular economy experts and waste management companies as well as pipe manufacturers were interviewed to clarify how well polyvinylchloride (PVC) and high density polyethylene (HDPE) plastic materials can currently be recycled. In addition, it was investigated whether nowadays used cable protection pipes could be replaced by recycled plastic pipes or biobased plastic pipes. Plastics that were used at the construction sites were PVC, HDPE, polystyrene (XPS), polypropylene (PP), cross-linked polyethylene (XLPE) and ethylene-propylene rubber (EPDM). There is no further processing of recycled PVC into the recycled plastic granulates in Finland, which is why PVC plastic is sold abroad. In addition, due to the chlorine content of PVC, incineration is not recommended for PVC products. For this reason, it would be good to replace PVC plastic in cable protection pipes with HDPE plastic. HDPE plastic can be recycled in Finland, and further processed into recycled plastic granulates, which can be used for pipe production instead of virgin material. There are no bio-based pipes yet in Finland, which is why waste management companies do not have experience in recycling bio-based pipes. Based on the literature review, no clear differences were found in the carbon dioxide emissions of HDPE and PVC plastic manufacturing. However, HDPE and PVC pipes made from recycled plastics were clearly lower in emissions than similar virgin plastic pipes. At the moment, within the framework of for recyclability and carbon footprint, the best option would be an HDPE cable protection pipes made of recycled plastic, as the use of recycled plastic itself reduces the carbon footprint of the pipe.