Often asked: How Much Does Concrete Shrink?

How much does concrete shrink when it cures?

As concrete hardens and dries it shrinks. This is due to the evaporation of excess mixing water. The wetter or soupier the concrete mix, the greater the shrinkage will be. Concrete slabs can shrink as much as 1/2 inch per 100 feet.

How long does concrete continue to shrink?

Unfortunately, concrete continues to dry for 12 to 18 months. As drying continues the concrete shrinks and the joints widen.

What is the shrinkage of concrete?

Shrinkage is an inherent property of concrete. The shrinkage in concrete can be defined as the volume changes observed in concrete due to the loss of moisture at different stages due to different reasons.

Does concrete shrink or expand when it dries?

A.: When it first dries, concrete shrinks and undergoes structural alterations that make some of the shrinkage irreversible. Thus, even if it is later resaturated, the initial drying shrinkage isn’t fully recovered.

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How do you reduce concrete shrinkage?

Minimize drying shrinkage – Keep the total water content of the concrete mixture as low as is practicable for the intended application. This can be achieved by using a high content of hard, rigid aggregates that are free of clay coatings, and by using mid-range or high-range water-reducing admixtures.

Is cracking in concrete normal?

When you see a crack in your concrete slab or wall, your first assumption is typically that something has been done wrong–but that’s not always the case. Actually, concrete cracks are very common, some are even inevitable.

Is it OK if it rains after pouring concrete?

Heavy rain can cause problems to freshly poured concrete as it can wash out some of the cement from the mix. This can weaken the surface of the concrete, making it a softer consistency and decreasing the strength of the concrete.

How thick does concrete need to be to not crack?

Applied-load cracking.



In residential concrete, 4 inches is the minimum thickness for walkways and patios. Garage slabs and driveways should be 5 to 6 inches thick if any heavy truck traffic is anticipated, otherwise 4 inches is adequate.

Can concrete get wet while curing?

QUESTION: I’ve been told that new concrete should be kept moist for at least three days while curing. ANSWER: Keeping concrete moist helps the curing process. Concrete hardens as a result of a chemical reaction, called hydration, between cement and water, not because it dries.

What are the main factors that affect concrete shrinkage?

Factors Affecting Shrinkage in Concrete:

  • Cement Content: As a general rule, the increase in the richness of concrete mix which leads to drying shrinkage.
  • Water Content:
  • Aggregate:
  • Curing:
  • Presence of Excessive Fines in Aggregates:
  • Chemical Composition of Cement:
  • Temperature:
  • Humidity:
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What is BPO shrinkage?

Call center shrinkage is the number of agents actively taking calls divided by the number of agents who are not available for any reason. Those reasons can include: External Shrinkage Factors: Holidays & vacations.

How long does it take for 4 inches of concrete to cure?

When waiting for concrete to dry, keep these timeframes in mind: 24 to 48 hours – after inital set, forms can be removed and people can walk on the surface. 7 days – after partial curing, traffic from vehicles and equipment is okay. 28 days – at this point, the concrete should be fully cured.

Are concrete expansion joints necessary?

Expansion joints are virtually never needed with interior slabs, because the concrete doesn’t expand that much—it never gets that hot. Expansion joints in concrete pavement are also seldom needed, since the contraction joints open enough (from drying shrinkage) to account for temperature expansion.

How big can a concrete slab be without expansion joints?

Usually, expansion joints should be no farther apart than 2 to 3 times (in feet) the total width of the concrete (in inches). So for a 4 inch thick concrete slab, expansion joints should be no more than 8 to 12 feet apart.

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