Coastal structures III

In the last three decades, an extensive literature has documented different concrete mixtures and supplementary cementitious materials (SCMs) to reduce CO2 emissions from concrete production. Recent findings show the importance of low pH concrete for improved marine life on the structure, and identify surface roughness as the most effective factor in design of bioreceptive concrete. Few studies have investigated the design of breakwaters by modifying the chemical composition of concrete, with limited information regarding the exact composition of these mixtures. Effort is needed to investigate the suitability of these materials for the construction of low-coastal structures (LCS) to decrease CO2 emissions and improve the bioreceptivity of concrete armor units during the breakwater lifetime. In this work, different SCMs, water-to-powder ratios and aggregates are investigated for the proposal of feasible concrete mixtures to construct LCS, showing as example the manufacture of Cubipod units for Homogeneous Low-Crested Structures.

The purpose of this experimental modelling study was to provide data on the hydraulic performance and stability of low-crested and conventional rubble mound breakwaters (RMBW) constructed using ecologically-friendly armour units under various wave conditions. The University of Ottawa, the National Research Council of Canada (NRC), and ECOncrete Tech. Ltd. collaborated to develop and conduct the physical testing program. This experimental program is essential to promote environmentally-friendly armour units in the design of new coastal structures (such as Baker et al., 2018), as well as ecological retrofitting of existing coastal structures. The physical tests were conducted between June 2023 and August 2023 at NRC's Ocean, Coastal, and River Engineering Research Center in Ottawa, Canada. ECOncrete's Coastalock armour units were tested in various configurations at a 1/15 scale using two-dimensional low-crested and conventional RMBW models under severe wave conditions to investigate their hydraulic performance and failure mechanisms.