Concrete is a multipurpose material used in different aspects of construction. Perhaps, for this reason, it exists in different grades, each determining the strength of the concrete after the first twenty-eight days of construction. Each mixture of concrete serves a purpose. For instance, the mix needed to build a sidewalk is not the same for a bridge. When working with concrete, it is essential to pay special attention to the mixture for the best results. Here, we look at the best mixtures for different purposes.
Four materials make up what concrete is. They are sand, aggregate, water, and sand. Each of these materials serves a particular purpose, and understanding how these materials work gives you an insight into how best to mix them together. The materials are:
Cement: This primary component of this material is calcium oxide. There are other ingredients such as aluminum, silicon, iron, and other elements—the material acts as the bonding agent holding all other materials together. Despite the exceptional cement strength when it cures, the strength can’t be compared to what rock and sand have. Cement is why the tensile strength of concrete is weak and needs rebar. You must note that the compressive strength of concrete is not determined by how much cement you use; cement only gives better adhesion.
Aggregate: This is a crushed rock that is responsible for the compressive structural integrity of the concrete. This material, which some called gravel and sand works together to give the concrete its high compressive strength.
Sand: Apart from adding to the compressive strength of concrete, it also acts as the filling agent blocking all the spaces and air pockets between the crushed rocks.
Water: This is the catalyst for the chemical change that makes the cement bind the sand and rock. It is also what makes the concrete usable as without, the forming, mixing, and finishing will not be possible.
Mixture of Concrete Based On the Construction
One-Two-Two Mix Ratio: Where the concrete is required for constructions such as fence posts, small precast, garden furniture, poles, and all types of work in the form of thin sections, this is the best mixture to use. For every one part of cement, there should be two aggregates and two of sand.
One-Two-Three Mix Ratio: When erecting cisterns, storage tanks, well curbs, sewers, watertight works, and any construction that would be subject to high stress, the mixture is best at one part of cement, two parts of sand, with three-part aggregates.
One-Two and Half-Three and Half Mix Ratio: A mixture that is one part of cement to two and a half parts sand and three and a half parts aggregate is best used for reinforced concrete works, beams, floor slabs, ordinary floors, steps, driveways, pavements, stairs, arches, etc. The water level, however, differs from medium to small, depending on the wok.
One-Two-Four Mix Ratio: This mix ratio of one-part cement to two parts of concrete and four parts of aggregates is best for building walls, sills, silos, lintels, bridges, etc. It can be used generally for structures subject to vibrations or those exposed to frost or water.
The best concrete mixture is a matter of function, and what is best for one construction may fail woefully at another. So, the function and prevailing conditions should always be considered.