# Assessment of Premature Failures in Concrete Railway Ties: A Case Study from Brazil

## TL;DR

This study examines why concrete railway ties in Brazil deteriorated prematurely after ten years, finding that chemical reactions and moisture significantly reduced their strength.

## Contribution

The study identifies the combined effects of alkali–silica reaction and sulfate attack as key drivers of premature concrete tie failure in Brazilian railways.

## Key findings

- Deterioration in concrete railway ties was driven by alkali–silica reaction and sulfate attack.
- Prestressing-induced stresses and moisture exposure reduced mechanical strength by 66% in one group of ties.
- Internal swelling reactions and poor drainage accelerated degradation in low-prestress zones.

## Abstract

Prestressed concrete railroad ties are the global standard for railway infrastructure due to their structural stability, durability, and cost-effective maintenance. However, their long-term performance is often compromised by premature deterioration. This study investigates the degradation of prestressed concrete railways ties from a Brazilian rail line after ten years of natural exposure, emphasizing critical implications for infrastructure maintenance. Two groups of ties, separated by 30 km, were analyzed through physical property assessments, petrography, X-ray diffraction (XRD), and scanning electron microscopy/energy dispersive spectroscopy (SEM/EDS). The results reveal that deterioration was driven by the combined effects of alkali–silica reaction (ASR) and sulfate attack, confirmed by the presence of (N, C)ASH gels, ettringite crystallization, and cryptocrystalline materials within cracks and voids. Prestressing-induced stresses and environmental moisture further accelerated degradation, leading to a 66% reduction in mechanical strength in the T1 group. These findings demonstrate that internal swelling reactions and moisture exposure synergistically accelerate deterioration in prestressed concrete ties, particularly in low-prestress, poorly drained zones.