RE-DOSING OF SUPERPLASTICIZER TO REGAIN THE ORIGINAL SLUMP FLOW IN CEMENT MORTAR
This research was aimed to find out the amount of second dose of superplasticizer needed to regain the original slump flow in cement mortar after it losses certain percentage of slump flow. The test was conducted on the mortar mix with the paste (ratio of volume of cement to volume of void in the sand) content of 1.6, water to cement ratio rang from 0.3 to 0.4, initial SP range from 1.15 to 2.4 percentages and Naphthalene based superplasticizer. Re-dosing of SP was done after 60, 90 and 120 minutes respectively. The result had concluded that,the required second dose of SP depends on the percentage of slump flow loss and water cement ratio used for the particular mix. Fresh properties of concrete mainly depends on fresh properties of mortar. This mortar can be used to make concrete which help to solve slump loss problem of ready mix concrete during delivery time. The required or original slump/slump flow can be regained after re-dosing a suitable dose of SP in the construction site.