SEDL / STP / STP1116-EB / STP16360S

Thermal Conductivity of Several Concretes as a Function of Moisture

Ashworth, T
Professor and Head of the Physics DepartmentAssociate Professor in the Mining Engineering Department, South Dakota School of Mines and Technology, Rapid City, SD

Ashworth, E
Professor and Head of the Physics DepartmentAssociate Professor in the Mining Engineering Department, South Dakota School of Mines and Technology, Rapid City, SD

Pages: 15    Published: Jan 1991

Download this paper for $25 PDF (280K)          View License Agreement
Abstract

A simple laboratory system for measuring thermal conductivity has been developed which utilizes a heat-flux transducer on each side of the specimen. Because previous studies have characterized the thermal contact resistance, the need to embed temperature sensors in the specimen was avoided. The specimen can be sealed in a plastic bag. This enables measurement of the thermal conductivity of specimens with varying amounts of moisture. Four different concretes have been studied: a standard concrete, a micro-concrete used for model structural analysis, a standard shotcrete with metal fibers, and a foamed light-weight (cellular) shotcrete. Thermal conductivity increased linearly with moisture up to high moisture levels; the values at 27°C range from 1.00 to 1.85 W/(m-K) for concrete, 1.46 to 2.03 W/(m-K) for microconcrete, 0.98 to 1.83 W/(m-K) for shotcrete, and 0.14 to 0.36 W/(m-K) for cellular shotcrete. Data have a reproducibility of better than 2%. The conduction processes in the materials are discussed briefly.