5 Mistakes to Avoid When Using Cement

The use of cement on site is subject to precise rules, the non-compliance with which can seriously compromise the quality of structures. The first and most common mistake is incorrect dosage. Insufficient dosage reduces mechanical strengths and concrete durability. Excessive dosage is wasteful and can cause shrinkage cracks. Compliance with prescribed dosages (350 kg/m³ for standard reinforced concrete) is imperative.

The second common mistake is excessive water addition. Many workers add water to facilitate implementation, but each liter of excess water reduces concrete strength by about 2 to 3 MPa. The water/cement ratio should never exceed 0.50 for reinforced structures. Prefer the use of a plasticizer to improve workability without compromising strengths.

The third mistake is inadequate cement storage. Cement left on the ground, exposed to moisture or bad weather, degrades quickly. Wet cement sets in lumps and loses a significant portion of its strength. Always store cement on pallets, in a covered and ventilated area, and consume it within 3 months of manufacture.

The fourth and fifth mistakes are insufficient curing and premature formwork removal. Curing, which keeps the concrete moist for at least 7 days, is essential for optimal strength development. Without curing, the 28-day strength can be reduced by 30 to 50%. Premature formwork removal can cause irreversible deformations and cracks. Respect the minimum deadlines: 24 hours for vertical elements, 7 days for floor slabs, and 21 days for spans exceeding 6 meters.