Many construction contractors are very familiar with the tools and equipment of their trade. While equipment is one of the most important parts of a safe and effective construction process, the type of cement that is used is just as important. Here are four types of cement that are used in mixers for modern construction.
Gray Portland Cement
Gray portland cement is by far the most common type of cement in use today. It is a hydraulic cement, meaning that it can be poured in underwater locations and be left out in the rainy weather while it dries without detrimental effects. Additionally, gray portland cement is divided into several categories based on its composition and intended uses.
Type 1 Gray Portland cement is general-purpose cement that is used in urban construction where no specific resistances are required other than weather resistance. It is commonly found in buildings, sidewalks, railways and bridges.
Type 2 Portland cement is used where contact with high-sulphate groundwater is necessary, such as in some Great Lake states.
Type 3 is a fast-curing cement that is used for structures that must be put into service quickly.
White Portland Cement
White Portland cement is a mixture that is very similar to Gray Portland except for its color. The chemical composition of white and Gray Portland cement is virtually identical except for a lower iron content and additional aggregates or inorganic pigments to produce the desired colour. These factors make white Portland cement significantly more expensive per square foot than gray cement.
Because of its higher price point, white Portland cement is not an economical building material. Instead of being used in structures, white cement typically finds its place in decorative work or the most prestigious architectural projects. The mixture of aggregates and pigments can be tweaked to provide a range of pastel colours, with the most common being light reds, greens, and blues.
High-Strength Cement
Heavy-duty construction projects like skyscrapers and suspension demand high-strength concrete to support the additional stress of their construction. High-strength concrete, designed to have a compressive strength greater than 5800 psi, must be created from advanced, energetically modified cement mixtures to produce their high-compression properties.
Energetically modified cement gains its strength from the chemical reactions that take place while it is mixed. Unlike Portland cement, which is made from naturally cementitious materials such as lime and clay, energetically modified cement is produced when pozzolans are dissolved and react with calcium hydroxide. Pozzolans are materials such as fly ash and volcanic ash that do not have cementitious properties in their solid state.
Masonry Cement
Masonry cement, also known as mortar, is a necessary ingredient for any bricklaying project. Unlike Portland cement and high-strength cement, which must be mixed using industrial mixers, masonry cement can be purchased in ready-mix form by the bag full. Masonry cement is mixed with lime and water to create a strong bonding material for stonework.
Masonry cement shares many similarities in composition with Portland cement, but also has distinct advantages. Masonry cement is ready to apply much sooner than Portland cement after drying, greatly reducing the amount of time that is necessary for certain stonework projects. However, masonry cement is not suitable for large-scale construction projects, as it dries to brittle to create a reliable concrete.
The formulation and specification for the type of cement that you are using can be easy to overlook even for an experienced contractor. You should spend just as much time choosing the concrete for any project as you do for your machinery and other tools. Keep these guidelines in mind and you will always know that you are using the right type of cement for the project that you are working on.
