From time to time, MCR will collect together a series of papers that relate to a particular issue or theme. Such a themed issue will be preceded by an editorial giving an overview of the papers contained in that volume. The theme for this issue relates to factors effecting concrete durability.
Concrete needs to be durable in order to be competitive and sustainable, and much research development is aimed at producing durable designs, materials and techniques that result in concrete constructions that will last for an anticipated period, anything from 10 to 150 years, without undue maintenance.
This MCR issue contains six papers, three of which relate to corrosion in some form, two to drying shrinkage and the other to expansion fracture cracking.
Such a selection is not exhaustive, since durability, its attainment or loss has many underlying and contributing causes.
Corrosion in uncracked and cracked concrete (Otieno et al., 2010) is a common cause of concrete downgrading, and cracked width opening and water-to-binder ratio, as well as composition, are relevant factors.
The paper by Azad et al. (2010) relates to induced corrosion in concrete beams aimed at analytical prediction of residual flexural strengths.
On the issue of predicted modelling, the effect of corrosion at the reinforcing steel–concrete interface is important. The paper by Chernin et al. (2010) proposes a new numerical model of this phenomenon based on bond mechanisms resulting from adhesion and friction.
Drying shrinkage cracking of concrete containing fly ash as fine aggregate replacement (Seo et al., 2010) indicated a slight improvement over that of OPC-only concretes.
A different slant on the matter of overall concrete shrinkage is dealt with by Kwan et al. (2010) taking account of the effect of aggregate shrinkage in particular granite rock from Hong Kong. Shrinkage was offset by aggregate pre-treatment. By contrast, expansive fracture can induce cracking, sometimes referred to as silent demolition, and the paper by Laefer et al. (2010) covers the action of several expansion agents.
The issue of durability is likely to recur, albeit from different standpoints. If that is the case, a second themed issue may well be published.
