The use of plastic waste as fine aggregate in the self-compacting mortars: Effect on physical and mechanical properties

• Plastic waste in self-compacting concrete (mortar) production.
• Effect of plastic waste type on self-compacting mortar performance.
• Effect of the plastic waste form on interface cementitious matrix/plastic.

This work aims to study the possibility of recycling waste plastic (polyethylene terephthalate (PET) used for the bags manufacture) as a fine aggregate instead of sand in the manufacturing of the self-compacting mortars. For this, an experimental study was carried out to evaluate physical and mechanical properties of the self-compacting mortars (SCMs) with plastic wastes. The sand is substituted with the plastic waste at dosages (0%, 10%, 20%, 30% and 50% by weight of the sand).The physical (bulk density, porosity, water absorption and ultrasonic pulse velocity testing) and mechanical (bulk compressive and flexural strength) properties of SCMs were evaluated and a complementary study on micro-structural of the interface of cementitious matrix and plastic waste. The measurements of physical and mechanical properties show that, in term of the density for materials, the mortars with 50% of plastic waste give better results than other proportion of the waste. Those mortars have a mechanical strength acceptable for lightweight materials. According to results obtained a reduction of 15% and 33% for mortar containing 20–50% plastic waste. A microscopic study of the interfacial zone (plastic–binder) has shown that there is an adhesion between plastic and cement paste (case 28 days of hydration).