Development in the construction industry technology has led to the invention of new types of concrete with their different uses. The properties of concrete when both in a plastic liquid state and when it is a hardened mass depend on the chemical composition and the proportions of the components used in the mixture. The guide will explore the different types of concrete in kenya.
What is concrete?
Concrete is a popular construction material that is obtained by mixing cement water and aggregates in given proportions which react chemically and bind themselves together to form a mass that hardens over time. the hardened mixture is what we call concrete.
Common Types of concrete in Kenya
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Reinforced cement concrete. (RCC)
This type of concrete is made up of cement, fine and coarse aggregates, admixtures, and steel reinforcements. steel is the most suitable reinforcement material because they have almost the same coefficient of thermal expansion due to this it is more compatible with concrete than other metals. reinforced concrete is commonly used in slabs, beams, columns, and building foundations. It is also used in water tanks, retaining walls, chimneys, concrete sewers, and pipes.
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Plain cement concrete(PCC)
This is a basic concrete mix type consisting of cement, aggregates, water, and admixtures in relative proportions.PCC is strong in compression but weak in tension due to a lack of reinforcements like steel. The general concrete mix design ratio for PCC is usually 1;2;4. Or 1.3;6..This type of concrete is used in foundations after the hard strata has been reached. it is also used in making concrete blocks, verandas, slabs, and open parking.
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Precast concrete
Precast concrete structures are cast cured and transported to the site where they are erected using cranes. The precast structure is manufactured using moulds that have reinforcement cages in them. Precast concrete is used in precast slabs, beams, columns retaining walls culverts, and many others.
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Ready mix concrete
This ready plant-made concrete is loaded onto delivery trucks known as transit mixers which have provisions that constantly rotate keeping the concrete in motion to prevent setting. Retarders are added to the concrete mix to slow down the setting process giving an allowance for transportation to the site and placing. quality checks are performed both at the plant and site. ready mix concrete is used for monolithic concreting of the roof slabs and beams.
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Prestressed concrete
Prestressed concrete structures are made of high-strength concrete and high-strength steel tendons in addition to the standard reinforcements. When The tendons are prestressed, the stress from the tendons is transferred to the concrete, therefore, improving the deflection resistance, load capacity, and overall performance of the structure. prestressed concrete structures are commonly used in the construction of prefabricated buildings.
How to cure for new concrete in Kenya
The process of keeping concrete moist and hydrated to ensure it develops maximum strength is known as curing. when it is not cured, it is prone to cracking and collapsing.
Wet curing is covering concrete with a sheet and keeping it soaked for 7 days, avoid placing weight it until the curing process is complete.
Another method of curing concrete is by adding a curing compound to it which locks in the moisture without the constant need of rewetting it.
Concrete takes about 28 days to completely cure and gain maximum strength.
Bottomline
To conclude, when concrete is not cured properly, placed, and compacted properly it will not achieve its maximum strength potential, therefore it is important to note that when using concrete for construction in Kenya, the liquid concrete when delivered to the site should be workable for it to be placed and compacted properly.
