Regulation of setting time for improving casting conditions in slip-form concreting

Abstract

The optimal conditions in slip-form concreting can be achieved when the initial compressive strength of concrete in the remoulding zone under the form lies between 0.2 and 0.3 MPa. High environmental temperature and low rate of slip-form movement frequently require retardation of the setting process and, on the contrary, low environmental temperature and high rate of moving can require acceleration of the setting. In order to give the constructors an effective tool for regulating the hardening process, well planned laboratory work has to be carried out before the worksin situ begin. This paper presents an approach and method of testing based on an example of a specific project, where the construction was poured by means of slip-forms in the high-temperature conditions of an Israeli summer. It is shown that laboratory data obtained can be used for improving casting conditions if the constructors are able to plan the rate of casting to the nearest shift and to comply with their plan.