关键词: 粉煤灰;水泥;强度;电阻率;化学收缩

Abstract: The evolution of compressive strength, electrical resistivity, chemical shrinkage and hydration products of the cement pastes with fly ash were investigated.The water to binder ratio of the cement pastes were 0.4, and the content of fly ash was 0%, 20% and 40% in mass, respectively.The electrical resistivity was measured by a non-electrode resistivity apparatus.The chemical shrinkage was tested according to ASTM C1608-12.The results show that the compressive strength of the sample with 20% fly ash is just less than that of the control by 5% at the age of 250 d.The compressive strength,electrical resistivity and chemical shrinkage are all decreased at the age of 3 d with the increase of fly ash.The relationship between compressive strength and electrical resistivity at 3 d appears to linear.Among the hydration products, the amount of C-S-H gel is reduced with the incorporation of fly ash.But ettringite could be detected by the XRD and TG analyses at the age of 3 d.

Key words: fly ash;cement;strength;electrical resistivity;chemical shrinkage