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What happens if I pour a mixture of dry concrete in a place with a lot of water?

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What happens if I pour a mixture of dry concrete in a place with a lot of water?

Concrete is a widely used construction material that consists of cement, water, and aggregates (such as sand, gravel, or crushed stone). The proportions of these ingredients affect the properties and performance of concrete, such as its strength, durability, and workability. To achieve the desired results, concrete must be mixed and placed properly, following the recommended guidelines and standards.

One of the most important factors in concrete mixing and placement is the water-cement ratio, which is the ratio of the weight of water to the weight of cement in a concrete mix. The water-cement ratio determines how much water is available for the hydration of cement, which is the chemical reaction that causes concrete to harden and gain strength. A lower water-cement ratio means less water and more cement, resulting in a stronger and more durable concrete. A higher water-cement ratio means more water and less cement, resulting in a weaker and more porous concrete.

The optimal water-cement ratio for concrete depends on various factors, such as the type and grade of cement, the size and shape of aggregates, the intended use and exposure conditions of concrete, and the required workability and consistency of concrete. Generally speaking, the water-cement ratio should not exceed 0.6 for most applications, and it should be as low as possible without compromising the workability and quality of concrete.

What is dry pouring of concrete?

Dry pouring of concrete is a method of placing concrete without adding water to the mix beforehand. Instead, dry bags of prepackaged concrete mix (such as Quikrete or Sakrete) are dumped directly onto a prepared subgrade or into a hole or formwork, and then moistened with water over a period of several hours by spraying or misting. The idea is that the dry concrete will absorb the water from the surrounding soil or atmosphere and harden gradually.

Dry pouring of concrete is sometimes used for small-scale projects that do not require a high level of strength or durability, such as filling fence-post holes, anchoring mailbox posts, or repairing minor cracks or holes in existing concrete. Dry pouring of concrete is also sometimes used as a shortcut or a cost-saving measure by homeowners or contractors who do not have access to proper mixing equipment or materials.

What are the disadvantages of dry pouring of concrete?

Dry pouring of concrete is not recommended as a placement method for concrete slabs or structures that need a solid foundation or support. Dry pouring of concrete has several disadvantages that can compromise the quality and performance of concrete, such as:

  • Inadequate hydration: Dry pouring of concrete does not ensure that the cement will be fully hydrated by the water. There is no way to control or measure how much water is absorbed by the dry concrete or how evenly it is distributed throughout the mix. Some parts of the dry concrete may get too much water, while others may get too little or none at all. This can result in uneven curing, cracking, shrinking, swelling, or weakening of concrete.
  • Low compressive strength: Dry pouring of concrete reduces the compressive strength of concrete, which is its ability to resist crushing forces. The compressive strength of concrete depends largely on the water-cement ratio. A higher water-cement ratio means less cement per unit volume of concrete, which means less bonding between the cement paste and the aggregates. This reduces the cohesion and adhesion of concrete, making it more susceptible to failure under load. Dry pouring of concrete can increase the water-cement ratio significantly above the optimal range, resulting in weak and brittle concrete.
  • High porosity: Dry pouring of concrete increases the porosity of concrete, which is its tendency to have voids or spaces within its structure. Porosity affects the permeability and durability of concrete. A higher porosity means more pathways for water, air, chemicals, or other substances to penetrate into or through concrete. This can cause corrosion, erosion, staining, freeze-thaw damage, or other forms of deterioration in concrete.
  • Poor appearance: Dry pouring of concrete affects the appearance and finish of concrete. Dry pouring of