Assessment of Alkali-Silica Reaction Potential in Aggregates from Iran and Australia Using Thin-Section Petrography and Expansion Testing.

The alkali-silica reaction can shorten concrete life due to expansive pressure build-up caused by reaction by-products, resulting in cracking. Understanding the role of the aggregate, as the main reactive component, is essential for understanding the underlying mechanisms of the alkali-silica reaction and thereby reducing, or even preventing, any potential damage. The present study aims to investigate the role of petrographic studies along with accelerated tests in predicting and determining the potential reactivity of aggregates, including granite, rhyodacite, limestone, and dolomite, with different geological characteristics in concrete.

Determining the water content of nominally anhydrous minerals at the nanometre scale.

The amount and distribution of water in nominally anhydrous minerals (NAMs) are usually determined by Fourier-transform infrared spectroscopy. This method is limited by the spot size of the beam to the study of samples with dimensions greater than a few micrometers. Here, we demonstrate the potential of using photoinduced force microscopy for the measurement of water in NAMs with samples sizes down to the nanometer scale with a study of water concentration across grain boundaries in forsterite.

Characterizing concrete corrosion below sewer tidal levels at chemically dosed locations.

Unexplainable concrete softening below the water line has been observed by Sydney Water in their gravity sewer network, some of which is subjected to corrosion control methods using chemical ferrous chloride (FeCl) dosing of the wastewater. We applied a combination of physical and chemical tools to determine the properties of the top 20 mm of concrete cores recovered from sewer pipes. These techniques consist of neutron tomographic imaging, scanning electron microscopy, hardness mapping, and pH profiling.

Detection of Gaps in Concrete⁻Metal Composite Structures Based on the Feature Extraction Method Using Piezoelectric Transducers.

A feature extraction methodology based on lamb waves is developed for the non-invasive detection and prediction of the gap in concrete-metal composite structures, such as concrete-filled steel tubes. A popular feature extraction method, partial least squares regression, is utilised to predict the gaps. The data is collected using the piezoelectric transducers attached to the external surface of the metal of the composite structure.