Abstract: During concrete placement in high temperature seasons, large daily temperature variation on the concrete surface will lead to nonlinear temperature gradient, which causes tensile stress. If the stress exceeds the tensile strength of the concrete in corresponding concrete age, surface cracks will occur. Distributed optical fiber was employed to carry out real-time online monitoring of temperature on the surface layer of the concrete block, and subsequently to determine the area influenced by solar radiation and daily air temperature variation. Moreover, a FEM model was established to perform feedback analysis on temperature field and creep stress field. Results showed that for a concrete block with 3m-thick layer, the area from the surface to the depth of 50cm was largely influenced by daily temperature variation and solar radiation.

Key words: distributed optical fiber, solar radiation, temperature gradient, feedback