Other measures for controlling the heat of hydration and sulfate resistance, such as the use of blended cements which provide an equivalent or better performance, are becoming more common in certain areas.ĪSTM Type III (CSA Type HE), High Early Strength: Portland cement that develops strength sooner than normal cements and is suitable for rapid construction, early form removal, cold weather, or when the concrete must be put into service quickly.ĪSTM Type IV (CSA Type LH), Low Heat of Hydration: A slow reacting cement which minimizes heat generation used in concrete for massive structures, such as bridge supports or dams. Other measures for controlling sulfate resistance, such as the use of blended cements which provide an equivalent or better performance, are becoming more common in certain areas.ĪSTM Type II-MH (CSA Type MH), Moderate Heat of Hydration: Moderate sulfate-resistant cement that also reduces heat generation caused by hydration. Type I cement is commonly found in general construction applications such as most buildings, bridges, pavements, precast and masonry units, etc.ĪSTM Type II (CSA Type MS), Moderate Sulfate Resistance: Portland cement used for concrete exposed to soil or water with moderate sulfate concentrations.
The standards above address the following types of portland and general use cement:ĪSTM Type I (CSA Type GU), Normal / General Use: General purpose portland cement suitable for concrete that does not require special properties. All Lehigh Cement products are manufactured to comply with applicable CSA, ASTM, AASHTO or API Standards. Portland cements conform to the American Society for Testing and Materials (ASTM) C150 Standard Specification for Portland Cement and Canadian Standards Association (CSA) A3001. Other concrete applications include precast products, pipe, masonry, oil and gas drilling and soil stabilization.Įngineers and construction professionals often specify a certain type of portland cement to meet special requirements of conditions.Ĭement types are defined by a variety of standards and specifications. Most cement is used to produce ready mixed concrete, which is delivered to construction sites in the familiar trucks with revolving drums. Cement is ground so finely that it will pass through a sieve that is fine enough to hold water. The result is a fine powder that is now considered portland cement. The pellets of red-hot clinker are cooled and ground with a small amount of gypsum.The intense heat triggers chemical reactions that form an intermediate product called clinker. The materials are combined, blended and ground together, then processed in a huge industrial furnace called a kiln, which reaches temperatures of 1,450° C (2,650° F) or more.Limestone, the source of calcium, makes up about 80% of the raw materials for cement. They are quarried at the cement manufacturing plant or shipped from nearby.
Raw materials rich in these elements include limestone, sand and clay. Cement-making requires calcium, silica and small amounts of alumina and iron.Portland cement manufacturing is a three-step process: Today, portland cement is not a brand name, but the generic term for the type of cement used in most concrete. He named it “portland” cement because concrete made with it resembled a highly prized building stone quarried on the Isle of Portland. Aspdin received the first patent on portland cement in 1824. These qualities explain why one material, concrete, can build everything from skyscrapers and sidewalks to highways and dams.Īlthough natural cement dates back to the Romans, by the late 1800s builders were turning to its manufactured counterpart, portland cement, for higher strength and more consistent performance.Įnglish bricklayer Joseph Aspdin is widely credited for the invention of modern portland cement. When freshly mixed, concrete can take any shape or form when hardened, it’s strong and durable. Through a chemical reaction called hydration, the mixture sets and hardens into concrete. When combined with water, cement forms a paste that coats the sand and gravel. Cement typically accounts for 10% to 12% of the concrete mixture.Ĭement acts as the binding agent or glue in concrete. It’s the fine grey powder that, when mixed with water, sand and gravel or crushed stone, forms the rock-like mass known as concrete. While the terms are often used interchangeably, concrete and cement are not
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