Title:
Concrete Armor Units for Breakwaters
Author(s):
Nina J.C. Fozein Kwanke, Eddy A.B. Koenders, W. Jeannette Bouwmeester-van den Bos, and Joost C. Walraven
Publication:
Concrete International
Volume:
31
Issue:
10
Appears on pages(s):
34-40
Keywords:
relative temperature, stresses, hardening phase, cracking.
DOI:
Date:
10/1/2009
Abstract:
Historically, resistance to wave action has been the main design criterion for large concrete armor units. To study the influence of fabrication practices on cubic armor units, six different concrete mixtures were first evaluated using small test cubes. Tensile and compressive strengths and adiabatic temperature development were evaluated for the concrete mixtures during the initial 7 days of curing. To simulate the hardening process at the macro scale, the data were used in finite element analyses, which were used to evaluate temperatures and stresses. Several parameters were varied in the analyses, including the volume of the blocks, the concrete mixture properties, formwork type, stripping time, and ambient conditions. Analyses showed that temperature differentials do have the potential of creating stresses sufficient to crack the concrete. Specifically, the analyses indicate that blocks may lose shape as their corners break off, or they may fracture completely through the thickness and fall apart. Cracking and breaking observed in blocks on an existing breakwater agree very well with the cracking patterns predicted during the analyses.