Experimental study on the thermal expansion coefficient of high-strength/performance concrete at early ages

In this paper the thermal expansion coefficient of high strength/performance concrete with water-cement ratio of 0.3 at early ages was measured more accurately by improving Yang Yang proposed method previously, in which the temperature change was given to concrete specimens in a lower temperature region from -1 to 5°C. The results showed that a good linear relationship exists between the strain and change of temperature, and the ascending line coincided approximately with the descending line, the influence of autogenous shrinkage was controlled effectively and could be neglected by the method; the coefficient of thermal expansion drops rapidly immediately after initial setting and reaches the minimum at about age of 1 day, then it rises again negligibly to 3 days and converges on a steady value.