Case Studies in Construction Materials (Dec 2022)
The effect of using shredded plastic on the behavior of reinforced concrete slab
Abstract
The present work investigated the usage of recycled plastic waste in slabs. The mechanical properties of concrete were studied by testing 21 standard cylinders with 5 %, 10 %, and 15 % RPET and RPEP for the slump, density, compressive, and splitting tensile strengths. It shows that while RPET improved workability more than RPEP, both ingredients decreased concrete density by up to 9.8 %. The RPET group provided greater strength than the RPEP by 10 %. Slight variations in RPET and RPEP led to a decrease in splitting tensile strength. Seven 500x500x110mm reinforced concrete slab samples were tested experimentally to determine the influence of 5 %, 10 %, and 15 % RPET and RPEP substituting aggregate. The slabs were sorted into control, RPET, and RPEP groups and tested using a line load at midspan, comparing failure mode, initial crack load, ultimate load, and deflections for each group. All samples failed due to flexure. RPET slabs cracked less than the control and RPEP slabs. Replacing coarse aggregate with RPEP reduces first cracking loads by 3.2–34.3 %. The experimental flexural load tests showed that the ultimate load decreased by 13.9–21.6 % when RPET was employed and by 2.4 %, 7.9 %, and 14 % when RPEP was used. A decrease in deflection was observed when 5 % of RPET and RPEP were used, while deflection was increased for 10 % and 15 %. In experiments, slab failure and cracking loads were less than the expected theoretical loads. The work incorporates FEM slab simulation. The finite element method matches experimental data for computing the ultimate loads for RPET and RPEP slabs. The finite element method did not match how the slab responded to load. Finite element analysis generates more flexible slab behavior than experimental testing.
