General Contractor Practice Exam

What is the best method to reduce surface bleed water in concrete work?

1. Add more water

2. Decrease the amount of fines

3. Increase fines

4. Use a curing compound

The correct answer is: Increase fines

Using an increased amount of fines in the concrete mix is effective for reducing surface bleed water. Fines, which consist of smaller particles like silt and clay, help to create a denser mix and improve the overall particle packing within the concrete. This denser packing allows for better bonding between the particles, which can effectively reduce the volume of water that rises to the surface during the setting process. As a result, the incidence of surface bleed water can be minimized. Adding more water would generally increase the likelihood of bleed water, as a higher water-to-cement ratio leads to more water being present in the mix. Decreasing the amount of fines can lead to a coarser mix, which may not compact as well and can also result in increased bleed water. Though curing compounds are important for controlling moisture and curing the concrete once it is set, they do not directly address the issue of bleed water during the initial pour and setting phases. Thus, increasing the amount of fines is the most effective method to reduce surface bleed water in concrete work.