If water gets in the cracks and freezes over there will probably be problems.
Pouring concrete driveway in rain.
If possible tent the pour with tarps to keep rain from mixing with the concrete.
Also lasted 40 years.
Unpredictable summer thunderstorms can wreak havoc on a concrete pour.
The more rain that mixes with the semi solid concrete the more likely it is that the slab will fail.
Pour the concrete onto the existing damaged concrete in the same way and trowel to a smooth finish and hopefully there is no more rain to cause any damage.
Water is a key component of all concrete mixing with cement and causing it to hydrate and gain strength.
The concrete that was poured in the 1970 did not crack or flake off.
The reason why builders avoid pouring concrete in rain deals with the overall strength of the concrete.
But after freshly mixed concrete has been placed water in the form of a driving rain can do much more harm than good.
The biggest problem you may be faced with is the effect the rain may have had on the surface of the concrete.
Pouring concrete in the rain can compromise its strength increasing the tendency for dusting and scaling to develop.
Rainwater can cause a new concrete surface to become soft which in turn decreases the abrasion resistance and strength of the concrete while increasing the tendency for dusting and cracking to develop.
The rules are different today because of cheap and lazy.
When pouring concrete in the rain the best thing to do is focus on damage minimalization and check to ensure that your concrete is well poured later on.
This is vital if you re in the early stages of a pour when the skies open.
Pouring concrete vs pouring rain.
In addition to causing pits in the surface of the concrete when the raindrops hit it rain falling on uncured concrete can change the water cement ratio in the concrete s top layer.
If it was not covered prior to the onset of the rain if the hardening was not very far along by that time and if there was enough rain falling with enough force the rain may have washed some of the cement out of the concrete.
The new slab can be walked on in about 12 hours and i would leave it to dry for about a week before continuing with the construction of your building.
As concrete dries one of the worst things that can happen is for rain to start falling.