Concrete building blocks are made of cement. Solid cement blocks are heavy and expensive. They usually weigh 40 to 45 pounds each. They are larger than normal building bricks. The standard size is 8” depth by 8” width by 16” length. They are hard to work with and take a lot of time to install because of their weight and bulk. There are other cinder block types that are less heavy and easier to work with.
Sometimes construction of a building calls for use of these lighter weight, but still larger sized building blocks. They speed up the construction of cement walls. They are mostly hollow and can be used in place of solid cement blocks. The hollowness allows them to be filled in with concrete or it can be left open to provide some insulation.
Cement blocks are made of a combination of Portland cement, aggregate and water. The aggregate used in standard cement blocks is usually stone or gravel. The aggregate used in cinder blocks is usually fly ash or in other words, the cinders from burning coal. The result is a lighter weight masonry block that tends to have a rougher surface than that of a solid cement block.
When laying cinder blocks, masons will offset one row of cinder block with the next row in order to stabilize them. They will also put a line of mortar in between rows.
Reinforcing Cinder Block
Sand or gravel can be used to fill up the holes in cinder blocks to reinforce them. Concrete is often poured into the hollow spaces in cider block to offer greater strength. This can be difficult to do without a rebar. A rebar is an iron rod placed vertically in the hollow spaces and also adds to the strength of the concrete.
Cinder blocks have to be threaded over the rebar before they can be set into place. This may pose a problem for longer sections of cinder block walls. In these cases a type of cinder block called speed blocks are used.
Speed blocks are concrete blocks that are open ended or shaped like an H. They can be manipulated over the rebar and slid into place. In construction of large lengths of concrete these speed blocks are used in place of cinder blocks.
There are a variety of shapes of concrete blocks manufactured for a variety of purposes. There are wedge shaped blocks on a base called capping units. There are notched blocks used in window or door sills. There are blocks shaped specifically for corners. Specialty blocks can be obtained for virtually any construction need.
Concrete block is most commonly used for commercial buildings. It has a sterile, plain appearance. It can be painted and washes easily. There are also many coatings available that add waterproofing and extra insulation.
Although cinder blocks are light weight when compared to solid concrete blocks, the weight quickly adds up when working with a whole load of them. You should always be cautious when moving any type of construction material. You can seriously injure yourself if you lift too much weight or try to move them to fast.
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