EFFECT OF SUPERPLASTICIZER ON THE HYDRATION OF A MIXTURE OF WHITE PORTLAND-CEMENT AND FLY-ASH

Hydration of a mixture of white portland cement with 25 wt. % fly ash in the presence and absence of 1% lomar-D has been investigated. Both fly ash and the superplasticizer act as a water reducer and increase the setting time. The compressive strength of white portland cement at 28 days is increased with the addition of fly ash. The strength is further increased in the presence of a superplasticizer. Porosity measurements indicate that increase in strength is a result of decrease in porosity. It is found that after 7 days of hydration the reaction between CH and fly ash increases; however, the extent of this reaction is lower in the presence of a superplasticizer. The superplasticizer is probably adsorbed at the cement and fly ash surfaces.