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Current Research Areas

Service life prediction models for reinforced concrete in the SA context

Service life prediction models exist at an international level, but it is essential that locality-specific models also be developed and calibrated, in view of the specificity of local environmental exposure conditions. Two such models are under development: one for chloride ingress into a wide variety of different concrete types, and the second a carbonation-corrosion model that couples CO2 ingress with a tendency for subsequent corrosion.

Low-clinker cements

It is imperative that modern concrete be formulated with as low a clinker factor as possible in the binder component, to minimise the carbon footprint of such concrete. This project considers practical ways of reducing the clinker factor of concrete using a combination of improved packing and reactivity of the fine filler materials, based largely on finely ground limestone and potentially reactive fly ash.

Durability and deterioration studies

This research has been a consistent theme in CoMSIRU for many years. Currently, these studies relate to deterioration of concrete sewer pipes, for which PhD work is being done in order to better understand the deterioration processes in such sewers, and characterisation of the inter-tidal zone for chloride ingress into concrete. Work on deterioration of continuously reinforced concrete pavements has also been undertaken.

Sustainability and resource minimisation studies

A PhD study was recently concluded that laid out a novel framework to assist structural concrete engineers to design for more sustainable concrete structures. Work is also on-going on understanding how to minimise resource usage of concrete materials, and a study on local bamboo in construction is being completed.

Fatigue reliability and long-term monitoring of railway bridges

Developments in structural health monitoring of bridge structures are enabling the capture of information on as-built structural behaviour of these structures. Such information is useful for the assessment of the condition and reliability of bridges. This project is focused on the fatigue behaviour of concrete railway bridges. In particular, box-type sections will be considered. A monitoring system has been developed for the Olifants River Bridge, located in Vredendal.

Bridge management systems

Visual inspection is the predominant bridge assessment technique employed by most current BMS. In South Africa, substantial visual inspection data has been collect in the last decade. However, these data have not been analysed to determine predominant deterioration mechanisms. This project seeks to gain deeper understanding of deterioration mechanisms in bridges located in the Western Cape.

Long-term performance of repaired reinforced concrete structures

There is a dearth of information on the long-term performance of repaired reinforced concrete structures. Quite often, infrastructure owners are unaware of the effectiveness of repair and strengthening interventions and their long-term performance. In particular, the long-term behaviour of new cementitious grouts for structural repairs as well as fibre reinforced polymers (FRP) for structural strengthening is not well understood.

Ambient vibration monitoring of concrete dams

Finite element modelling is a powerful tool for simulating structural system behaviour. In this body of work, updated finite element models will be used to predict the future behaviour of dams. Updating of the FEM models will be based on ambient vibration testing.

Numerical modelling of the swelling effect of concrete structures

The chemical reactions involving aggregates, cement paste and water may lead to the swelling of concrete. Such volume changes lead to premature deterioration and, in some cases, structural failure. The problem of concrete swelling has been widely reported, especially in concrete dams. A number of numerical models have been proposed to simulate the swelling action and compute the structural response to this internal loading. This project is focussed on developing computational models for implementation in standard finite element analysis codes.