Prediction of Freezing Temperature inside Concrete Crossties at the Rail Seat Area

Air-entrained high performance concrete (HPC) crossties or ties (alternatively called sleepers outside of North America) have been observed to suffer structural and material degradation at the rail seat area (RSA), including freeze-thaw damage. The manifestation of any damage at the RSA is hazardous because future high-speed railroad lines utilizing HPC crossties will be installed in regions across the United States with extensive freeze-thaw temperature cycling. To better understand the extent of cyclic freezing temperatures at the RSA, an environmental study was undertaken to measure the internal temperature at various locations of instrumented HPC crossties that were installed in a track for 1 year. The experimentally measured internal temperature values are compared against the results of a pair of models (a solar radiation model and a one-dimensional, multilayered heat transfer model) that utilize only public weather data as model inputs. The pair of models is found to satisfactorily predict the freezing internal temperatures of concrete crossties, specifically during winter months. The validation of this temperature modeling expands the HPC crosstie practitioner’s set of tools necessary to better understand environmental design criteria of this critical piece of infrastructure with regard to freeze-thaw damage.