EFFECT OF PARTIAL SUBSTITUTE OF COARSE AGGREGATE WITH RECYCLED AGGREGATE ON CONCRETE STRENGTH
Keywords:
Recycle aggregate, Concrete, Demolition debris, Slump test, Density, Compressive strengthAbstract
An investigation into the use of recycled aggregate from crushed graded inorganic particles processed from used construction materials and demolition debris is reported. Six batches of concrete mixes with varying content of recycled aggregate from 0% to 100% in Steps of 20% were used. Physical property tests including specific gravity, moisture content, sieve analysis, shape index, fineness modulus, fines content, flakiness index, uniformity coefficient, Los Angeles Abrasion, water absorption capacity were carried out on the constituent materials of the concrete. The slump test to determine the workability of the mixes was also carried out. The compressive strength property characteristics for the different mixes studied. The test was carried out on bioth cylinder and cube specimens.
Results showed that workability and compressive strength of concrete mixes decrease with increase in percentage content of recycled aggregate in the concrete. However, the concrete produced with recycled aggregate recorded density values over 2400 kg/m3 while non of the cube strength is less than 20N/mm2. As the value of slump decreased from 35mm at 0% level of recycled aggregate in concrete mix to 17mm at 100% level of recycled aggregate content, the average compressive strength also decreased by about 12%, 10% and 6% respectively for 7-, 14- and 28-day curing ages. However, for the cylinder specimens, the percentage reduction in strength was between 38.14% and 34.85% at 7- and 28-day curing ages respectively.
