Cracks in concrete can be frustrating when you’ve just finished a project. At Express Concrete, we’ve been supplying high quality ready mix concrete across London since 1991, and we understand why concrete cracks and how to prevent it in your construction projects.
Why Does Ready Mix Concrete Crack?
1. Not Enough Curing Time
When concrete mixed on site dries too quickly, the surface can crack. This happens during hot or windy weather when moisture evaporates rapidly. Proper curing means keeping the mix concrete moist for several days after pouring.
2. Too Much Water in the Mix Design
Adding extra water might seem helpful, but it weakens ready mix and causes shrinkage cracks. At Express Concrete, we carefully control water levels in our concrete solutions.
3. Plastic Shrinkage
Fresh ready mix can lose moisture quickly, causing small, shallow cracks that look like spider webs within hours of concrete delivery.
4. Temperature Changes
Ready mix concrete expands in heat and contracts in cold. These movements create stress that leads to cracks, especially in areas with big temperature differences.
5. Uneven Settlement
If the ground isn’t properly prepared, parts of the concrete may sink more than others, causing stress and cracks in your construction projects.
6. Too Much Weight
Overloading concrete, especially before it fully hardens, can cause cracking. Always choose the right concrete strength for your project using quality materials.
7. Freeze-Thaw Cycles
Water that seeps into concrete can freeze, expand, and cause internal pressure and cracking. According to the British Ready-Mixed Concrete Association, this is particularly relevant in the UK climate.
8. Poor Quality Materials
Using low-quality materials results in weaker mix concrete that’s more likely to crack. Work with experienced suppliers who understand which concrete solutions work best for different projects.
How to Prevent Cracks
- Prepare the site properly: Ensure the ground is compacted and level
- Use the right mix design: Different construction projects need different ready mix options
- Add control joints: Strategic cuts help manage where cracks form
- Cure properly: Keep concrete moist for at least a week after concrete delivery
- Consider the weather: Avoid pouring in extreme conditions that might affect the concrete mixed on site
When to Call Professionals
While small cracks are normal, larger ones (wider than 3mm) or cracks that continue to grow might indicate a serious problem. If you notice these issues with your ready mix concrete, consult with experts.
FAQs About Concrete Cracks
Are all cracks in ready mix concrete a sign of poor quality?
No, some hairline cracks are normal as concrete dries and settles.
How can I tell if a crack is serious?
Cracks wider than 3mm, growing cracks, or uneven surfaces are more concerning.
Can I pour ready mix in cold weather?
Yes, but it requires special precautions like heated water and insulation.
How long should concrete cure before use?
For light foot traffic, wait 24-48 hours; for vehicles, wait at least 7-10 days.
Get the Best Results with Express Concrete
We’re committed to helping you achieve excellent results with our high quality ready mix concrete. Our concrete pumping and concrete delivery services ensure your construction projects run smoothly. Contact us today to discuss your concrete solutions and get a competitive quote for your next project.