Page 84 - ICJ Jan 2023

POINT OF VIEW COLLECTOR’S EDITION

Building durable structures in the 21st century*

P. Kumar Mehta and Richard W. Burrows

At the dawn of the 21st century, we are inheriting a world that has seen
unprecedented demographic, social, technological, and environmental changes
during the last 100 years. These changes have had a great impact on all industries,
including the construction industry. So far, the concrete construction industry
has met the need for housing and infrastructure in a timely and cost-effective
manner. We are now entering an era when the industry faces an additional
challenge: how to build concrete structures that are environmentally more
sustainable. Climate change resulting from the high concentration of greenhouse
gases in the atmosphere has emerged as the most threatening environmental
issue and, as discussed below, the construction industry happens to be a part of
the problem. 1,2
T he primary greenhouse gas is carbon dioxide and, during the 20th century, its

concentration in the environment has risen by 50 percent. Carbon dioxide is a major by-product
in the manufacturing of the two most important materials of construction: portland cement
and steel. Therefore, the construction industry needs to determine how future infrastructural
needs can be met without further increases in the production of cement and steel. Conservation
of these materials through enhancing the durability of structures is one of the ways by which
the construction industry can become a part of the solution to the problem of sustainable
development.

Some 2000-year-old unreinforced concrete structures, such as the Pantheon in Rome and several
aqueducts in Europe, made of slow-hardening, lime-pozzolan cements, are in excellent condition,
while the 20th century reinforced concrete structures that are constructed with portland cement
are quickly deteriorating. When exposed to corrosive environments like deicer salts and seawater,
serious durability problems have occurred in bridge decks, parking garages, undersea tunnels,
and other marine structures less than 20 years old. 3-5

The Indian Concrete Journal | November 2018 85