Cover Story Building Durable Structures From concrete mixes to waterproofing strategies By Alireza Biparva, B.Sc., M.A.Sc. W All photos courtesy Kryton International hen it comes to buildings, routine maintenance is expected on any structure as wear and tear is inevitable. However, the difference between small repairs and a major retrofit or rehabilitation is significant. Referring to De Sitter’s Law of Fives, 1 a major repair can be expected to cost roughly five times what routine maintenance would have cost. An all-out replacement will then cost five times what a major repair would entail. So, avoiding large-scale work of this nature is of the utmost importance for the financial viability of a concrete structure. With much of Canada’s infrastructure built in the 1950s and ’60s, deterioration has been occurring for more than half a century with much of the budget heading toward repair, maintenance, and inspection, instead of building for the population growth. This handicaps the future insofar much of the country’s infrastructure—including roads, highways, and bridges—are in dire need of repair. Governments shoulder this expensive task of inspection and repair. 2 In Ontario alone, an Auditor General’s report in 2009 reported there were 14, 800 bridges with an average age of 30 years and 3500 determined to be in either fair or poor condition. 2 Further, the Federation of Canadian Municipalities (FCM) estimates the country will incur a $123-billion infrastructure deficit, growing by two billion every year. 3 This does not say anything about building infrastructure for a growing population—this is only repairing that with which is already underserving. Repairs also have hidden costs that affect the bottom line of projects. These include traffic 10 July 2015 CC_July_15.indd 10 Co nstruction Canada 2015-06-22 10:17 AM