subject: Want To Know About Concrete Crack Repair [print this page] Before understanding about concrete crack, one must be familiar with the components that are used when a concrete mix is produced. A concrete mix consists of three main components or ingredients and these are:
Portland Cement- Cement combined with water acts like paste that coats the sand and aggregates in the mix. This paste then hardens and binds the sand and aggregates together.
Aggregates consisting of gravel, sand, crushed stone. Aggregates form as much as 60% to 80% of a typical concrete mix and therefore must be properly selected to be durable and properly controlled in order to produce a consistent concrete strength that is workable.
Water- Water is needed to chemically react with the cement which is known as hydration and provides workability with the concrete.
Why concrete cracks?
Concrete is one of the most durable and long lasting building materials if installed and mixed properly. A long lasting, durable, high strength and crack resistant concrete is possible where well established guidelines with respect to concrete placement are followed by the concrete contractors. But in some cases concrete gets cracked due to the following reasons and these are-
Excess water in the concrete mix- Water used in the concrete makes it easier to install but any excess water also reduces the strength of the concrete. Evaporation of excess water results in the shrinkage of the concrete slabs resulting in the appearance of cracks. It is estimated that concrete slabs can shrink as much as inch per 100 feet.
Rapid drying of the concrete- The possibility of cracks is there when there occurs drying up of the concrete in a speedy manner. Excess hydration or chemical reaction results in cracks appearing on the concrete slab.
Lacks of control joints- Control joints help the concrete in expansion or contraction of concrete structure and in reducing the impact of concrete cracks or if cracks do appear they do not cause weakness in the concrete. Lack of concrete joints do increase the possibility of concrete crack
If concrete of improper strength is poured while constructing the structure.
Other reasons include pouring the concrete on a frozen ground.
Concrete Crack Repair
Repairing the concrete crack due to the above mentioned causes can be repaired permanently without much cost if such concrete crack repair is done in the beginning stages itself. A concrete crack repair can be performed on three different sizes of cracks and these are Hairline cracks/Narrow Cracks, Large/Wider Cracks and Concrete Foundation or Concrete Slab Cracks. The concrete crack repair on each one of these sizes of cracks has been discussed about here under:
Hairline Cracks- Sealing of hair line concrete cracks can be done by using the Concrete Welder or Sealer that is available in a cartridge format at most of the large home improvement stores. Before applying the concrete welder make sure that crack is free from moisture and is clean. The next step involves opening the cartridge and squeezing the Concrete Welder directly into the crack. By using the scrapper smooth the Concrete Welder out. Any excess material must be wiped out and allow the Concrete Welder to dry out for half an hour. The crack is now filled and ready to use.
Large Cracks- For concrete crack repair of large cracks the area around the crack needs to be cleaned out before repairing and patching process. Any loose concrete must be brushed out by using wire brush or broom. The next step involves using the sledgehammer and cold chisel to widen and deepen the crack and then removing the debris with a wire brush and sweeping out the crack with a broom. Now clean up the crack with a mixture of trisodium phosphate or TSP and water. The final steps involves patching the crack using vinyl concrete patch cement and then fill the crack using the cement trowel. The crack must be packed well and smoothened at the top of the concrete patch cement. Do not forget to cover the repair with a piece of a gunny bag and damping it with water for two days. After two days the cement becomes dry and solid without any cracks.
Concrete Foundation CracksConcrete Foundation cracks are repaired by using polymer based aggregates for filling the deeper areas of the crack and using special sand. There are foundation crack repairer starter kits available at leading home improvement stores and these products are helpful in concrete crack repair of concrete foundation cracks.
