This project studied an innovative concept for introducing, monitoring, and adjusting prestressing forces within concrete crossties in the field under variable loading and support conditions using “Adaptive Prestressing System (APS)”. With the use of a fuse made of shape memory alloys (SMAs), it was proven that APS is able to apply prestressing in the field (not manufacturing plant). The prestressing force can be adjusted as needed at areas of interest in the crossties and eliminated from undesirable areas where prestressing causes cracking. Through testing 1/3 and 1/2-scale crossties equipped with APS, it was proven that this new concept can increase significantly the rate of crosstie production (cost-effectiveness) while at the same time eliminating common problems associated with the current manufacturing procedure such as early-age splitting cracks. The next step toward the implementation of this technology is to test it in the field under real train loads. 

The final report is available.