eGate – for building durable and safe bridges

In bridge construction, concrete strength must be verified before the structure is opened to traffic – this is a standard requirement in modern projects. Traditionally, this is done by crushing test specimens or by measuring internal concrete temperature and calculating strength using maturity models (MPa).

However, early strength is not a reliable indicator of long-term durability. For example, many highway bridges built in the 1970s and 80s in Germany and France have required major repairs within just 30 years. In the U.S., the American Society of Civil Engineers (ASCE) currently classifies over 46,000 bridges as structurally deficient or in poor condition – even though many were originally designed to last over a century.

Strength development requires the right conditions

Recent research shows that long-term concrete strength only develops if curing conditions remain controlled. Temperature alone is not enough – other factors also influence strength development over time.

MPa values based on temperature data work well for estimating early strength, but are not enough to predict a structure’s true lifespan. If strength development is interrupted, structures may appear ready – but weaken prematurely in use.