In order to study the distribution law of concrete hydration heat temperature field and strain field in concrete single box and three chamber girder, a concrete box girder scaled-down(1∶2) model was cast in Laibin, 148 temperature sensors and 20 strain sensors were embedded in the concrete. Meteorological sensors were arranged, and the distribution law of hydration heat field of C60 high-strength concrete box girder was obtained through the analysis of field actual measurement data. The research results showed that the hydration heat of single-box three-compartment box girder was divided into three stages: temperature rise stage (0-24 h), rapid temperature drop stage (24-96 h) and smooth temperature drop stage (96-240 h). The average temperature of the box girder cross-section needed 179 h before it was lower than the entering temperature, the heat generated by the hydration of the box girder needed at least 7 d to be completely dissipated; the peak temperature of the whole cross-section was 24 h after pouring, and the highest area was at the pedicle axillary position, with the highest temperature reaching 90.2 ℃, and the maximum horizontal temperature difference of the top plate reached 32.2 ℃ at this time. Influenced by the layered pouring, the maximum vertical temperature difference of the side web reached 12 h after pouring 40.1 ℃, and the construction cold joints could be observed on the site. The temperature field distribution at the stalk axle was complicated, and the maximum transverse temperature difference at the stalk axle was 22.5 ℃ and the maximum vertical temperature difference was 29.9 ℃, and the transverse shrinkage strain at the surface of the stalk axil is smaller than the vertical one. The strain on the outer surface of the stalk axil is lower and constrained by the template, so the strain is smaller than that inside the stalk axil. it was calculated that there was a risk of vertical cracking in six pedicle axils, and the maximum shrinkage tensile stress was 1.51 times of the tensile strength.
