A study of high strength concrete

The thesis describes the initiation of a research programme which is in two parts:- (I) An investigation of possible methods of producing high strength concrete. (II) A study of the creep characteristics of these concretes. For convenience and clarity, therefore, the thesis is presented in two parts, each being suitably entitled so as to represent the present state of the investigations into the above two topics. The actual work embodied in each part of the thesis can be summarised as follows. Part I: “A preliminary investigation of the effect of hydrostatic pressure, applied during setting, on the strength of concrete.” A preliminary investigation into one possible method was carried out, the method being that of manufacturing concrete specimens under an applied pressure, the specimens also being subject to suction and vibration. Two test series were carried out, one to investigate the effect of intensity of pressure, the other to investigate the effect of time of application of the pressure. The apparatus for processing the concrete is fully described, and details and results of the above tests are given. The main conclusion drawn, is that the process is undoubtedly beneficial to the strength of concrete, both the intensity, and time of application of the pressure effecting the possible strength increase which can be obtained. The test specimens were cylindrical in shape, the size being restricted to that of 2” diameter by 2” long in order that reasonably high pressures could be obtained. Part II: “The design and development of a creep machine”. The design and development of a creep machine capable of testing a maximum of six small cylindrical specimens simultaneously is fully described. The specimens are located in the creep machine in tandem and are loaded by means of a system of lever arms, the maximum design load being 10 tonf, the diameter of the specimen being 2”. Due to the limited time available, development of the machine was not completed, and hence no preliminary creep tests were carried out.