Issue link: https://geospatial.trimble.com/en/resources/i/1415420
58 csengineermag.com august 2019 Case Study: Jubilee Church, Rome, Italy According to architects Richard Meier and partners, the Jubilee Church in Rome was "conceived as part of Pope John Paul II's millennium initiative to rejuvenate parish life within Italy." The project consists of the church itself as well as both secular housing and housing for the clergy. The church is most easily distinguished by the three large con- crete shells which are meant to represent the Holy Trinity. Given the symbolic importance of the shells, their appear- ance is an absolute priority. Thus, due to the fact that the shells need to remain in pristine condition, it was only nat- ural that "self-cleaning" TX Active® photocatalytic concrete was used to ensure that the shells would not accumulate stains due to smog. Completed in 2003, the photocatalytic shells have notably remained clean and white, performing constant self-maintenance. Bendable Concrete Bendable concrete presents an efficient alternative primarily in the construction and maintenance of infrastructure, where con- crete is subject to harsh weather conditions and extreme loading. The design which gives bendable concrete, or engineered cementitious composite (ECC), its impressive ductility is based off nacre, the substance that coats the inside of abalone shells. Nacre is composed of small aragonite platelets that are held together by natural polymers, allowing it to be both hard and flex- ible as platelets are free to slide side to side under stress. This effect is mimicked in bendable concrete by dispersing tiny fibers throughout. Victor C. Li of the University of Michigan, where ECC was first researched and invented, states that bendable concrete "can deform up to 3 to 5 percent in tension before it fails, which gives it 300 to 500 times more tensile strain capacity than normal concrete". It is of course this incredible ability to tolerate tensile strain that makes bendable concrete unique. This enormous increase in ductility suggests various potential applications. Firstly, in roads as well as other paved surfaces which must bear repeated loading of heavy vehicles, bendable concrete would crack less often, preventing further weathering primar- ily from road salts which corrodes steel reinforcement. Further, due to ECC's capacity to absorb greater quantities of energy without being damaged, it can be used to make reinforcing elements such as the dampers on the Seisho Bypass Viaduct in Japan, which is roughly 28 kilometers long. Dr. Li also states that ECC has been employed as earthquake resistance in tall buildings in Tokyo and Osaka and further suggests that ECC would be useful in underground construction as well as the construction of water infrastructure. However, before it can be more widely commercialized for such large-scale projects, bendable concrete must become more readily available. To be economically viable, it must be supplied efficiently and not overused on projects. But, it is paramount that design professionals be made aware of the product and its potential as they might otherwise overlook a promising con- crete option for structures that require the ability to deal with considerable tensile strain. Bendable concrete also has self-healing capabilities. Because bendable concrete keeps cracks relatively small, natural reac- tions within the hardened concrete generate "healing" prod- ucts through carbon mineralization and continuous hydration which repairs the cracks and restores the durability of the concrete. Bendable concrete is a promising technology that already has proven itself through commercialization by several companies. Photo: Edmund Sumner-VIEW, Alamy Stock Photo Bendable concrete is 300-500 times more ductile than conventional concrete. Photo: Victor C. Li