Pouring Concrete:11 Most Commonly New Mistakes You Made
1. Constructing under the bad weather
The influence of weather on whether the concrete can be poured successfully is crucial. Severe weather events, such as heavy rain, drought, severe cold, and exposure to the sun, can threaten the saturation of concrete facilities. Thereby greatly reducing the quality of pouring concrete. Because of this, concrete installation specialists and contractors will be very careful when choosing the time and month of pouring concrete.
Be sure to avoid rainy and winter seasons, as the high moisture increases the chances of rain or water seeping into the concrete. As for cold weather in winter, freeze-thaw phenomenon will also affect the quality of pouring. Summer is a relatively safe season, but storms and rain sometimes occur in the summer, in which case, professional contractors often use tarps to prevent liquids from seeping into the concrete. Pouring concrete when there’s a danger of frost is also a problem because concrete loses a tremendous amount of strength if it freezes before curing.
2. Pouring concrete under utility lines
You can lay utilities in pipes or into concrete, but you need to be careful about shear forces on cables or pipes. Utilities include power, communications. So each has its own code and requirements, and local engineers will guide you in. The concrete can rip through utility lines, causing leaks and breakdowns. Make sure you use a fine crushed stone and/or sand to buffer these tubes or pipes, so any movement in the concrete won’t destroy their contents.
3. Pouring concrete over aged
Pouring new concrete over old concrete can go wrong under many circumstances. If you want to do this, be sure to get professional advice from experts in the industry before you do it. It depends on the age and quality of the underlying concrete. In general, cracks, movement and instability under the concrete will spread defects upward through the new concrete overlay. If the site needs to be over poured and the bottom layer is damaged, install a geotextile between the old and new concrete to “float” the new concrete.
4. Pouring too thin
Concrete can not be too thin. Concrete is strong and durable only if it is thick enough. Make sure your concrete slab is no less than 4 inches thin. Six inches is the minimum thickness of a concrete slab. It takes 6 inches to support most types of heavy vehicle traffic.
5. Subjecting new concrete to excessive weight.
Concrete hardens quickly after pouring but remains vulnerable to damage in the first 28 days. You have to wait at least 24 hours and even pets can’t walk on newly fallen sidewalks or slabs. Don’t drive in the new lane for at least 10 days. After 10 days, you can drive a regular passenger car on concrete. After 28 days the concrete has reached full strength and a heavy-duty pickup truck or RV can roll into the driveway.
6. Poor quality of materials
In addition to water, you must make sure that the other materials that appeared in the concrete are tiptop. For example, the sand needs to be fine and not to be infiltrated by other particles. The shoddy concrete form can cause your structure to bend or even break off.
Finally, the fiber-reinforced materials(like pva fiber, macrofiber) and other similar materials embedded inside the concrete also need to optimize for the structure.
A decrease or increase in these materials is likely to damage the strength of the finished structure.
7. Not using reinforcement
Seldom do contractors know about concrete reinforcing fibers. These thin, short strands of plastic add a lot of strength and crack resistance to any kind of concrete project. Try to put a patch of fibers into each mixing drum load of concrete and mix as usual, you may find something different. The fibers spread out within the mix and help bind the hardened concrete together. They helped a lot.
8. Touching the concrete with bare hand
The cement in concrete is highly alkaline and you will get burned without knowing it. Avoid direct contact with concrete and handle the concrete with a shovel. Better wear gloves.
9. Too much crushed stone
Most DIYers mix cement on their own: mixing Portland cement, sand and gravel together.
This practice saves time and money (although you need to take out more energy).
But beware not to deceive yourself. The standard concrete formula is one portion of cement, two parts of sand, and three parts of clean gravel. Don’t skip. The gravel is filler so do not use any more than the recipe calls for.
10. Exposure to corrosive rebar
To prevent concrete from cracking, professional contractors often add steel rebars to concrete. But sometimes to save money you’ll use bare steel rods as reinforcement. But there is a soft spot of bare rebar is that it can be corroded and rusted by water that sneaks into the concrete. When steel rebar rusts, it expands, causing the concrete to crack under internal pressure. Therefore, for the long-term reliability of concrete, fiber reinforced concrete is recommended.
11. Wrong cement-to-water ratio
The correct proportion of water and cement is the key to determining the integrity of the concrete slab. Too much water will weaken the concrete, and not enough water will make it difficult to pour and spread.
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1. Constructing under the bad weather The influence of weather on whether the concrete can be poure