Why does concrete crack, even when it was poured well? Because concrete shrinks as it cures, and central Indiana adds clay soils, freeze-thaw winters and road salt on top of that. Some cracking is normal. Other cracks point to a problem underneath. Knowing the difference helps you decide whether you need concrete repair or just a closer eye on things.
Fresh concrete holds more water than the cement needs. As that extra water leaves, the slab shrinks slightly. The ground underneath resists that movement, and the slab pulls against itself. Concrete is very strong when squeezed but much weaker when pulled, so it cracks to relieve the stress.
That’s what control joints are for. These grooves, cut or tooled into the surface, create planned weak lines so the slab cracks along them instead of across the middle. A hairline crack running along the bottom of a joint means the joint is doing its job.
Timing offers clues. Fine cracks that show up within hours of a pour usually come from the surface drying too fast on a hot or windy day. Cracks that appear after the first winter more often trace back to soil movement, water or the base underneath.
Clay soils, common across central Indiana, swell when wet and shrink when dry. A slab sitting on clay moves with the seasons. In winter, water in the soil can freeze into ice lenses that push the ground upward. That’s frost heave, and it can lift one panel above the next.
The concrete itself goes through freeze-thaw cycles too. Water soaks into the surface, freezes and expands. De-icing salt speeds that up, which our guide to de-icing salt and concrete explains.
Many crack problems start before the first truck arrives. These are the details worth asking about at any estimate:
Our guide to concrete thickness and reinforcement covers that last point in more depth.
Even a well-built slab has neighbors. Tree roots grow under sidewalks and lift them. Downspouts that empty beside a driveway wash out the sub-base and leave voids, and the slab sinks into them. A loaded moving truck or dumpster on a residential driveway can crack panels in an afternoon. Water is behind a lot of this, which is why drainage and grading deserve attention before any pour.
Not sure where yours falls? Our guide on whether to repair or replace concrete walks through the decision.
Filling a narrow crack with a flexible crack filler keeps water and weeds out, which slows freeze-thaw damage. It won’t fix movement underneath, so a crack that keeps widening needs a closer look.
It depends on the cause. Golden Paw’s warranty covers problems caused by work done incorrectly, not damage that happens afterward, such as from de-icing salt. If you see a crack you’re unsure about, let us take a look.
No honest contractor can promise concrete will never crack. What a contractor controls is the base, the joint layout, the mix and the curing. Golden Paw Concrete backs every project with a 3-year workmanship warranty covering problems caused by work done incorrectly. Call or text (317) 672-0966 or request a free estimate, and we’ll look at your cracks or plan new concrete built to handle Indiana winters.
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