Leaderboard

Well it depends on a lot of factors, however limit prescribed by ACI committee is fine. In order to get a good understanding of crack control I would like to refer Advanced reinforced concrete design by P.C. Verghese. Please go through the page 30 topic shrinkage and thermal cracking where Author has derived the minimum percentage of steel to control shrinkage cracks. He also recommends 0.003 percent. So on both faces it comes to 0.006 which is exactly equal to recommendation of ACI 224 R-01 http://books.google.com.pk/books?id=uXqXP6pEEsUC&pg=PR3&lpg=PR3&dq=advanced+reinforced+concrete+design+by+p.c.+varghese+pdf&source=bl&ots=hqxOR_udqx&sig=Fpn3F0WMD8UVONN1Sax43r5C5vU&hl=en&sa=X&ei=Zc9gVLOeI8yu7AaD0IGgCA&ved=0CB8Q6AEwATgK#v=onepage&q=advanced%20reinforced%20concrete%20design%20by%20p.c.%20varghese%20pdf&f=false