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http://www.nationalpost.com/life/homes/story.html?id=1238272
Cement: just like(stale) bread?
It's The Staff Of Life
Susan Down, National Post
Published: Saturday, January 31, 2009
Concrete seems as common as dirt to most people used to either walking on it or using it for home improvement projects. "I've mixed up concrete, poured it in the ground and stuck a fence post in it, says David Guptill. "It seems pretty straightforward." Ordinary consumers often make the mistake of calling it cement, says Mr. Guptill, who explains the difference in culinary terms: Cement is the flour and concrete is the bread.
That bread is the staff of life for the construction industry. Mr. Guptill, a vice-president with Lafarge Canada, knows that when it comes to supplying concrete for major projects such as high-rise condos, that grey stuff isn't a commodity, it's a carefully chosen product.
Modern concrete is stronger and more versatile than ever before. Compressive strength used to average around 35 MPa (megapascals), rising to 70 MPa and more today. Product names are trademarked, some sounding like monikers for foreign luxury cars: Agilia, Chronolia, the UltraSeries. Mr. Guptill estimates his company has about 400 mix designs. "They are like state secrets in our industries," he says. Another concrete giant in the southern Ontario market, Canada Building Materials, has products called Flow-Fill, First-Up and Eko-Crete. The choice depends on the use: Fast-strengthening concrete means the forms can be stripped more quickly; self-levelling concrete means less tamping down and other prep work. The addition of ingredients such as plasticizers allow modern concrete into intricate forms and crevices.
Concrete has taken on a new appeal as an eco-friendly product. The ingredients are easy to find everywhere. "As a base material, it's the second most plentiful on the planet next to water," says Mr. Guptill. The components are cold-mixed, unlike asphalt or steel. Because ready-mix concrete has a 90-minute shelf life from batch plant to dump site, it is very seldom transported further than 50 kilometres, which results in less transportation pollution. It's like the 100-mile diet for construction.
Big foundation pours are major logistical events. In January, 2006, the pour (handled by Lafarge) for the 54-storey North Tower of the MintoMidtown project at Yonge and Eglinton set a record (which has since been broken) for the biggest continuous pour (3,136 cubic metres in 11 hours). "There were 100 trucks dedicated all day long," says Evan Wittrup, operations manager, construction for MintoUrban Communities. "It was like a military operation." And a mighty big loaf of bread.
Cement: just like(stale) bread?
It's The Staff Of Life
Susan Down, National Post
Published: Saturday, January 31, 2009
Concrete seems as common as dirt to most people used to either walking on it or using it for home improvement projects. "I've mixed up concrete, poured it in the ground and stuck a fence post in it, says David Guptill. "It seems pretty straightforward." Ordinary consumers often make the mistake of calling it cement, says Mr. Guptill, who explains the difference in culinary terms: Cement is the flour and concrete is the bread.
That bread is the staff of life for the construction industry. Mr. Guptill, a vice-president with Lafarge Canada, knows that when it comes to supplying concrete for major projects such as high-rise condos, that grey stuff isn't a commodity, it's a carefully chosen product.
Modern concrete is stronger and more versatile than ever before. Compressive strength used to average around 35 MPa (megapascals), rising to 70 MPa and more today. Product names are trademarked, some sounding like monikers for foreign luxury cars: Agilia, Chronolia, the UltraSeries. Mr. Guptill estimates his company has about 400 mix designs. "They are like state secrets in our industries," he says. Another concrete giant in the southern Ontario market, Canada Building Materials, has products called Flow-Fill, First-Up and Eko-Crete. The choice depends on the use: Fast-strengthening concrete means the forms can be stripped more quickly; self-levelling concrete means less tamping down and other prep work. The addition of ingredients such as plasticizers allow modern concrete into intricate forms and crevices.
Concrete has taken on a new appeal as an eco-friendly product. The ingredients are easy to find everywhere. "As a base material, it's the second most plentiful on the planet next to water," says Mr. Guptill. The components are cold-mixed, unlike asphalt or steel. Because ready-mix concrete has a 90-minute shelf life from batch plant to dump site, it is very seldom transported further than 50 kilometres, which results in less transportation pollution. It's like the 100-mile diet for construction.
Big foundation pours are major logistical events. In January, 2006, the pour (handled by Lafarge) for the 54-storey North Tower of the MintoMidtown project at Yonge and Eglinton set a record (which has since been broken) for the biggest continuous pour (3,136 cubic metres in 11 hours). "There were 100 trucks dedicated all day long," says Evan Wittrup, operations manager, construction for MintoUrban Communities. "It was like a military operation." And a mighty big loaf of bread.