Structural Behaviour of Low Carbon, Functionally Graded, and Reinforced Concrete Using Distributed Sensing
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Authors
Yager, Jacob
Date
2024-12-12
Type
thesis
Language
eng
Keyword
Reinforced Concrete , Functionally Graded Concrete , Low Carbon Concrete , Distributed Fibre Optic Sensing , Digital Image Correlation
Alternative Title
Abstract
The production of cement is responsible for 8% of global carbon emissions. To minimize embodied carbon in reinforced concrete structures, efficient design and low carbon materials must be utilized. For this to occur, increasingly complex and efficient designs require accurate models developed from robust experimental data. Furthermore, the use of low carbon materials requires experimental verification of adequate performance. Thus, this thesis explores the use of concrete embodied carbon reduction strategies such as low carbon concrete (LCC), and functionally graded concrete (FGC) (the layering of multiple types of concretes to meet performance goals (e.g., material savings, durability, etc.)) through a series of tests monitored with distributed sensing.
Structural testing was completed on LCC, FGC, and conventional reinforced concrete slender beams, deep beams, continuous beams, one-way slab strips, and direct tension specimens, monitored with distributed fibre optic sensing and digital image correlation. From these tests, several discoveries were made about reinforced LCC and FGC. For FGC, the location and shape of the functionally graded layers had a major impact on the overall structural performance. Depending on the location of layer boundaries, different effects of debonding cracks on overall capacity were observed. The debonding cracks resulted in lowered capacity in FGC slender beams, resulted in little effect on capacity in FGC one-way slab strips, and resulted in improved capacity in FGC deep beams. Furthermore, little to no difference in behaviour was observed between LCCs used in these studies and conventional concrete of similar compressive strengths. This included similar serviceability performance (cracking behaviour, strains at service loads, etc.) and ultimate capacity.
Distributed sensing also provided an opportunity to generate first-of-their-kind data sets that were used to develop a more in-depth understanding of reinforced concrete structural behaviour, results of which could be incorporated into improved design codes or finite element modelling techniques. Insights into flexural behaviour of one-way slab strips, strut and tie mechanisms of deep beams, the variability and distribution of restrained and unrestrained shrinkage, and the tension behaviour of reinforced concrete were uncovered. Lastly, the testing of continuous beams illustrated how crack patterns and locations affect the behaviour of statically indeterminate members.