INVESTIGATION OF DETERIORATED CONCRETE RAILWAY TIES

Some prestressed concrete ties placed on railway from Nanjing to Shang hai show map and longitudinal cracking. Up date to 1995, cracking happ ened in 9082 ties out of 20945 on 11.9 km railway in Shanghai and more than 85% ties were damaged at Shanghai railway station. Analyses on t he affected concrete ties indicate that periclase and ettringite are p ot involved in the expansion of concrete. The coarse aggregates were a lkali-silica reactive and were attacked by alkalis. Alkali-silica reac tion is a primary cause for deterioration of the railway ties.