Civil Engineers are well-prepared to tackle seasonal fluctuations, whether it’s extreme heat, extreme cold, or inclement rains. These fluctuations often present challenges for constructors that require smart tricks and tips to overcome. Concreting during the rainy season is one such challenge that can be managed with awareness.
Finishing concrete surface
Rain can have a significant impact on the quality of freshly poured concrete if it hasn’t reached its initial setting time of 30 minutes. Rainwater can disrupt the mixture and affect the curing process, leading to weakened concrete. Between the initial setting time and the final setting time (10 hours), rain may only cause aesthetic issues such as patch marks on the surface of the concrete. However, heavy rainfall can disturb the top layer of the concrete mix, potentially affecting its integrity. Once the concrete has reached its final setting time, rainwater can actually be beneficial for curing, as it helps to hydrate the concrete and promote its strength development. When pouring concrete during the rainy season, it’s important to keep these factors in mind to ensure proper curing and avoid potential issues with the quality of the finished concrete.
1) Water Content in the mixture
When the humidity in the environment and the wetness of raw materials such as aggregate and sand increase, it becomes crucial to pay attention to the amount of water being added to the mixture. To avoid going beyond the Design mix’s limit, excess water should be compensated for accordingly. This can be achieved by reducing the water-cement ratio through the addition of suitable admixtures, provided the client permits it. Taking these measures will help ensure that the mixture remains within the required specifications, even under conditions of increased humidity and wetness.
2) Waterproofing Admixtures
Concrete structures require protection from water infiltration, especially under hydrostatic pressure. One solution is the use of hydrophilic crystalline admixtures during concrete laying. These admixtures react with water and cement particles to form calcium silicate crystals. These crystals can effectively seal both the pores and microcracks in the concrete, preventing water passage.
Moreover, the reaction between the admixture, water, and cement particles continues throughout the entire life of the concrete. This means that even cracks that appear over time can be sealed. As a result, hydrophilic crystalline admixtures can help prevent the deterioration of concrete structures caused by water infiltration. They are a valuable addition to any concrete-laying process, providing long-lasting protection against water damage.
3) Timing
Prior to pouring concrete, it is crucial to take into account the weather conditions. It is not advisable to pour concrete during excessively wet or windy conditions. This is because such weather conditions can negatively impact the quality of the concrete, leading to problems such as cracking or uneven surfaces.
To ensure that the concrete sets properly, it is recommended to pour it during a period of dry weather that lasts for at least 12 hours. This will allow the concrete to dry and set correctly, providing a solid foundation for the structure that it will support. Therefore, it is important to keep track of the weather forecast and plan the concrete pouring accordingly to minimize any potential issues.
4) Combat Heavy winds
To ensure the quality of concrete structures, it is crucial to have strong and resilient shuttering in place before pouring the concrete. Without proper shuttering, heavy winds can cause bleeding which can result in shrinkage cracks. These cracks can compromise the structural integrity of the concrete and lead to safety hazards.
Therefore, it is essential to take precautions and prevent such cracks from occurring. One way to do this is by using high-quality shuttering materials that can withstand the forces of nature. Additionally, the shuttering must be properly installed and secured to prevent any movement or displacement during the pouring process.
It is also important to monitor weather conditions and plan the concrete pouring accordingly. If heavy winds or other adverse weather conditions are expected, it may be necessary to delay the pouring until more favorable conditions are present. By taking these precautions and ensuring the proper shuttering is in place, the risk of shrinkage cracks and other structural issues can be significantly reduced, resulting in a safer and more durable concrete structure.
5) Transportation of Concrete
Efficient routes for RMC (Ready-Mix Concrete) trucks must be determined beforehand to prevent traffic jams and congestion. RMC trucks typically have an open top, which means that any delays in delivery could result in excess water entering the chamber and ruining the concrete mixture. As a result, it is critical to identify the best accessible routes for these trucks to minimize the risk of such delays.
6) Assisting Covers
In order to ensure a successful concrete pouring process, it is important to prepare the site in advance by bringing along plastic tarpaulins and rainproof canvas. These materials will be used to cover the area where the concrete will be placed, with consideration given to the space required for compacting and finishing the concrete surface.
Additionally, it is advisable to cover any heaps of aggregate present on the site. This is because when aggregates become wet, they can increase the water-cement ratio, which can negatively impact the strength and durability of the resulting concrete structure.
Therefore, it is crucial to be proactive in protecting the materials and ensuring a suitable environment for the concrete pouring process. By taking these measures, the chances of achieving a successful concrete pour and a high-quality finished product will be greatly increased.
7) Visual Inspection
Once the rainstorm subsides, it is important to visually evaluate the damage inflicted on the concrete surface. This can be done by simply observing the area and noting any visible signs of damage. Another method is to perform a scratch test to determine the relative scratch hardness of the affected sections compared to those parts of the slab that are known to be in good condition. By doing so, it is possible to identify the extent of the damage.
However, for a more comprehensive and precise assessment, multiple core samples need to be taken from the affected area and sent to a laboratory for analysis using an electronic microscope. This approach enables a thorough and quantitative evaluation of the damage, allowing for a more accurate determination of the severity of the situation. By utilizing these techniques, it is possible to gain a better understanding of the damage to the concrete surface and take appropriate remedial measures.
8) Instant Repairs
If the surface of a concrete structure is found to be compromised, it is important to address the issue immediately after the rain has stopped. In such cases, minor reparations may be sufficient to rectify the damage. These repairs may involve using the same type of concrete as the original or applying a cement slurry to the affected area.
However, if there are numerous small areas of damage on a thin concrete slab, it may be more cost-effective to remove and replace the entire section. This approach would ensure that the repaired section matches the rest of the slab in terms of durability and appearance.
On the other hand, if a large isolated area in a thick concrete slab is damaged, a different approach may be required. In such cases, it may be possible to apply a thin layer of cement slurry after removing the damaged concrete. This technique can help restore the surface quality of the concrete without having to replace the entire section.
Conclusion
Mitigating damages to a concrete surface during a rainstorm requires proper preparation, accurate predictions, and timing. One effective approach is to build a protective enclosure using plastic tarpaulins around the work site before the storm hits. This can help prevent rainwater from coming into direct contact with the concrete, reducing the risk of damage.
In the event that rain begins to fall while concrete is being poured, it’s important to wait for the rain to pass before proceeding with finishing. Allowing the rainwater to drain off the concrete surface and avoiding any attempts to finish the concrete while it is wet can help prevent potential damage to the surface.
By being proactive in preparing for rainstorms and taking appropriate measures to protect the concrete surface, such as using a protective enclosure or waiting for rain to pass before finishing, potential damages can be mitigated, ensuring a successful concrete pour and a durable final result.