Heat Loss Compensation in Semi-Adiabatic Curing Test of Concrete

Abstract

An adiabatic temperature rise maximum, which must be measured through an adiabatic curing test using a specially designed curing chamber, is often imposed for early thermal concrete cracking alleviation. Curing tests conducted on site should be regarded as semi-adiabatic because in practice, for convenience and simplicity, they are not truly adiabatic. The measured temperature rise is lower in a semi-adiabatic curing test due to heat loss than the adiabatic temperature rise by a specimen size-dependent error and the provided heat insulation. A heat loss compensation method using measured temperature spatial and time variation and heat loss compensation for heat loss estimation is proposed to minimize such error. To verify method applicability, ten laboratory-made concrete mixtures were tested. To demonstrate how a semi-adiabatic curing test could become much less affected by imperfect insulation after heat loss compensation, as well as independent of specimen size, two ready mixed concrete batches, each cast into 0.5 and 1.0 m (1.64 and 3.28 ft) cubes, were tested. Adiabatic temperature rise errors were all within ±1.3°C (±2.3°F) with application of the proposed heat loss compensation.