Concrete mixing
The mixing procedure of the concrete was started by dry mixing the coarse
aggregate, sand, and rubber for about 1 min to insure distribution of the aggregates
and then the cement and fly ash were added and the concrete was dry mixed for another minute. The superplasticizer was added to the water and the water was
then added to the mixture and the concrete was mixed for 2 min and then let stand
for 1 min; then, mixed for another 2–3 min until consistency was observed