High-Performance and Sustainable Materials for Structural Applications

Each year, construction of new structures uses enormous amount of raw materials extracted worldwide and consumes huge portion of global energy. In addition, existing civil structures experience deterioration due to various factors during their service life. Replacement of all aging and structurally deficient structures requires significant cost and time, and could have tremendous negative impact on the environment. Therefore, strengthening of deteriorated structures to extend their intended lifespans can be a more economical and sustainable alternative. To limit the environmental and social impacts associated with the extraction and consumption of raw materials in construction sector, high-performance and innovative materials can be utilized for improved structural retrofits or designs. This can enhance the long-term sustainability by reducing life-cycle repairs and the associated negative impacts. However, the development and characterization of such high-performance materials as well as their judicious implementation in civil engineering applications are still challenging.

This research explores the use of advanced materials for sustainable design and retrofit of civil structures. These materials are basalt fiber-reinforced polymer (BFRP) composites, shape memory alloys (SMAs), and corrosion-resistant A1010 steel. BFRP bars are first employed as near surface mounted (NSM) reinforcement to increase the flexural capacity of reinforced concrete (RC) beams. Second, bond behavior between NSM SMA bars and concrete is investigated, and the SMA bars are used to strengthen RC columns subjected to seismic loads. Additionally, SMA wires and small-diameter strands are used to develop superelastic SMA/epoxy composites that can be used to strengthen concrete and steel members. The fabricated composites are tested under monotonic and incrementally increasing tensile loads, and fatigue loading. Moreover, tensile behavior of A1010 steel plates with different plate thickness and orientations is characterized and fatigue performance of bolted and welded A1010 steel plate connections is explored. Furthermore, to illustrate the economic, social, and environmental benefit of adopting A1010 steel in bridges, life-cycle cost (LCC) analyses are conducted on two case-study bridges designed with either A1010 steel or conventional carbon steel. Finally, a series of LCC analyses are performed to calculate the payoff time for A1010 steel for wide range of bridge cases. The materials studied in this research exhibited high mechanical properties and it was shown that their implementation to design or retrofit of civil structures can lead to more sustainable structures.