Winter can be a treacherous time for construction workers. But it's not just about the workers - the concrete can also be adversely affected. Since it's subject to freezing temperatures, it tends to harden more quickly, creating problems for the concrete mix. This makes it even more critical that contractors understand a few best practices when it comes to concrete pumping during the winter... So, before you embark on a concrete pumping project or contracting job this winter, here are some important questions you should ask as well as educate your employees on. This article will help ensure that your work is completed in a timely manner and with high quality.
1) Understanding The Importance of Monitoring:It is critical to monitor weather conditions and temperatures throughout the day. The process of concrete curing is a chemical reaction, and that chemical reaction requires a certain temperature and humidity for the best results. When temperatures drop below 40 degrees Fahrenheit, the chemical reactions in concrete are slowed down. This is known as cold weather concreting.
When the air temperature drops, it causes concrete to cool off more quickly, which in turn affects hydration. When you have a slower hydration process, it causes the concrete to be more susceptible to damage from freezing or drying out too fast. This can be very problematic for your construction project as it can cause cracking or even lead to failure in the end result of your project.
2) Air-Entrained Concrete May Be Necessary:Air-entrained concrete is essentially concrete that has microscopic air bubbles that are intentionally added to the mix. While these air bubbles can be harmful when it comes to strength, they do have their place. The air bubbles act as small chambers that absorb some of the water in the concrete. This can help prevent the water from freezing during a freeze/thaw process which could lead to cracking. Let your employees know what type of concrete you will be using, and if it is air-entrained concrete, make sure they are aware of its properties and how it may be used.
3) Using Admixtures & Modifications:Often when pouring in cold weather, the use of admixtures and modifications to concrete is needed. These admixtures can help improve the workability of the fresh concrete, increase strength, and even reduce bleeding and segregation.
4) Adequate Insulation Will Be Needed for New Concrete:It is important to ensure that your concrete is properly insulated and heated during cold weather. This will be necessary for any new concrete you are pouring as well as any curing concrete you already have. If this is not done correctly, it can lead to your concrete cracking and breaking apart when the temperatures get too cold. To ensure this doesn't happen, you need to plan your project in a way that provides the proper heat source for your concrete and make sure you have plenty of insulation materials available to keep the heat from escaping.
5) You Might Want to Increase the Amount of Portland CementWhen you're working with cold-weather concrete, you can increase the amount of Portland cement in your mix to help it cure faster. If you add more Portland cement, it will create more heat when it cures, which means that your mix will be more likely to stay above 40 degrees Fahrenheit while it cures. However, if you do this, you will have less room for error when it comes to calculating your water-cement ratio. Therefore, only make this change if absolutely necessary and proceed with caution.