INFLUENCE OF INCREASING C₃A AND SO₃ IN CLINKER FOR SEVERAL PHYSICAL PROPERTIES OF CEMENT

Abstract

Clinker with increased amounts of C₃A and SO₃（C₃A：10-14％, SO₃：1.1-2.5％）was prepared by an electric furnace, and Cement was prepared with adding a certain amount of reagent gypsum（Gypsum SO₃＝1.2％）and grinded until 3,300cm²/g fineness by bond mill. The physical properties and durability of the sample cement was investigated. As a result, as C₃A and SO₃ in clinker increased, the setting time tended to be accelerated and the compressive strength hardened at 3 days of age, but it dropped as the age of long term. Also, as C₃A in clinker increased, the dry shrinkage strain of mortar increased, and as SO₃ in clinker increased, the dry shrinkage strain of mortar decreased. As C₃A of clinker increased, the cumlative heat of hydration of cement increased. On the other hand, as SO₃ increased, cumlative heat of hydration increased at several days after adding water but declined after several days. As both increase, the hydration exothermic curve changes, and the hydrate formation rate varies depending on both components.