Hydration and strength of neat Portland cement

Abstract

Summary In order to examine the relationship between some of the mechanical properties and the degree of hydration of Portland cement, two different methods were used to prepare samples of hydrated cement paste. One method involved hydrating the cement in suspension for different lengths of time in rotating polyethylene bottles (water/cement ratio = 5). The dried powder was then compacted to different porosities. In the other method, the dry unhydrated cement was mixed with plastic beads in the ratio of l:3 by weight and compacted at 10,000 lb/in2 to give a porosity oJ about 38%, and then hydrated by immersion in water. These compacts, which were in the shape of discs of 1·25 in. diameter, were used to measure the modulus of elasticity, fracture strength and indentation hardness. This work indicated that these types of sample can be used to follow the characteristic change in mechanical properties with time and degree of hydration of the cement.