Except for the pre-packed repair materials, the composition of
the OPC, PFA and OCI mixes was the same as that of the
“Leeds control mix” used in the laboratories of CEMU14. The
composition of the Leeds mix is: 1 part of cement, 2.33 parts
of sand and 3.5 parts of gravel. The water/cement ratio for the
OPC concrete (control) is 0.55 to give a slump of 55 + 5 mm.
To achieve the same slump for both PFA and OCI mixes, trial
mixes were made to find the amount of water required to give
the same slump. In the case of the PFA mix the w/c ratio was
0.5 while the OCI mix did not require reduction of water to
achieve the same workability as that of the concrete mix. The
pre-packed repair materials were mixed with water according
the procedure recommended by the manufacturer.