Arup investigation found 'evidence of failed repair works' – report

The investigations carried out by UK engineering firm Arup have revealed that repair works had been carried out to stop corrosion of the steel reinforcement inside the columns by water that was absorbed through the concrete.

The absorption rate was found to be more than double what was expected of high quality concrete in place for 20 years.

The Times of Malta this morning reported that the repair works had however failed. Citing the Arup report, The Times reported that the water absorption rate was also found to be more than double what was expected of high quality concrete in place for 20 years.

Evidence of the repair works was found in the service tunnel underneath Mater Dei’s emergency department, which formed part of the initial structures erected in the first half of 1996.

“The report seen by this newspaper said the undated repair works had not been effective in stopping the corrosion and the mortar used was also dropping off the columns. This led to ‘a progressive reduction of column capacity’,” the newspaper said.

Reportedly, the Arup report found a high level of carbonation resulting in an increased risk of corrosion to the steel reinforcement in the concrete. The carbonation was “a sure sign” of low-grade concrete that used limestone aggregate rather than hard stone.

It is unknown from construction documentation made available to Arup whether quality checks performed between 1996 and 2000 during the construction phase had found limestone aggregate in the concrete.