The effect of pressure prehydration on the strength of hydraulic cement concrete

It appears that the rapidity of curing and the degree or ultimate strength of concrete can be influenced by both chemical and physical factors. The main function of the physical factors involved seems to be the creating of a more intimate combination of the cement and water which are the active ingredients. For example, finer grinding of the cement would present more surface area to the water; the application of heat would decrease the amount of surface tension of the water, in addition to speeding the chemical reaction, steam under pressure would force water into the porous particles of cement; and the retaining of water in the mix by protecting it from evaporation would insure a more complete hydration. It would logically follow that the application of pressure to force water into the cement particles would produce a more intimate combination of cement and water. The purposes of this investigation are as follows: (1) To determine if the use of pressure to force water into the cement particles will accelerate the curing of concrete. (2) To determine the optimum degree of pressure to be applied for a three-minute period. (3) To determine if the accelerated curing will yield a concrete which has a higher ultimate strength after a reasonable period. Tests of Set I are concerned with phases (1) and (2). Tests of Set II are a verification of the results of tests of Set l, under conditions of more rigid control. Tests of Set III performed in connection with phase (3). --Purpose and Object of Investigations, pages 4-5