Title: Temperature Rise and Strength Development in Laboratory-Cast Structural Elements Containing Slag
Author(s): S.J. Barnett, M.N. Soutsos, S.G. Millard, and J.H. Bungey
Publication: Symposium Paper
Appears on pages(s): 37-50
Keywords: fast-track construction; slag cement; strength development; temperature rise.
Sections of high strength concrete (target mean strength of 100 MPa) column elements were cast in the laboratory and cured in a temperature-controlled environmental room at conditions representing average summer or winter temperatures in the UK. In each case, the room was programmed to cycle with a 24-hour period between a minimum and a maximum temperature representing day and night variations. The elements were instrumented with embedded thermocouples and pull-out test inserts, for measurement of in situ strength. Temperatures were continuously recorded for at least seven days after casting. Strength development was assessed by means of both pull-out tests and compressive strength testing of drilled cores at ages up to 28 days. Temperature-matched curing of 100 mm cubes was also carried out using the thermocouple output measured from the column elements. In summer conditions, the temperature rise was observed to be lower in slag concretes than in portland cement concrete but despite this the measured strength development was significantly enhanced compared to standard cured (20 °C) control cubes. The in situ strength improvement was sufficient to allow slag concrete to be used in construction in summer without causing delays to fast-track construction schedules.