Possibility to use crushed pet plastic to replace the fine filler in concrete mixture

Introduction. The accumulation of non-degradable plastic waste, in particular polyethylene terephthalate (PET), is an acute environmental problem. Finding ways to recycle PET in building materials can reduce the load on landfills and conserve natural resources.

Aim. Experimental evaluation of the effect of partial replacement of fine aggregate with crushed PET plastic on the physico-mechanical properties of fine-grained concrete.

Materials and methods. Four concrete compositions were studied (cement: sand = 1:3, W/C=0.55): control (without additives) and compositions with the replacement of sand by volume by 5 %, 10 % and 15 % with crushed PET fractions of 2–5 mm. The 70 x 70 mm cube samples were tested for compressive strength, average density and water absorption were determined at the age of 28 days.

Results. It was found that the introduction of plastic leads to a decrease in average density (up to 8 % with 15 % PET) and compressive strength. The highest strength of the modified formulations was recorded at a dosage of 5 % PET (a decrease of 12.5 % relative to the control). A further increase in the plastic content to 15 % causes a sharp drop in strength (by 31 %) and a 2.1-fold increase in water absorption.

Conclusions. The optimal dosage, which provides acceptable characteristics for a number of building solutions, is the replacement of 5–10 % of sand by volume. The resulting material can be recommended for curtain structures, paving slabs and landscaping elements.

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