2. Experimental work
Table 1 shows the conditions and variables of the experiment to examine the physical, mechanical and sound absorbing characteristics of porous concrete according to the
target void ratio (TVR) and the recycled aggregate content
(RAC). The amount of admixture added to obtain fluidity was determined by means of a flow test.
2.1. Materials
The cement used for this study is normal portland cement whose specific gravity is 3.14 and blaine fineness is 3200 cm2/g, containing 21.4% of SiO2, 5.97% of Al2O3 and
62.72% of CaO.
Crushed aggregate and recycled waste concrete aggre- gate of 5–13mm in size are used. Table 2 shows their physical properties.
The admixture was a highly polymerized naphthalene sulphonate, which is a type of the super plasticizer (Mighty-
150) that improves the concrete quality through cement distribution action, see Table 3.
2.2. Test method
In order to determine the amount of the super plasticizer, the KS L 5111 flow table test was used. This test determines the required workability when manufacturing porous con- crete, prevents material separation and forms continuous porosity after hardening.
The experiment to determine void ratio was per- formed based on bPorous concrete void ratio experiment