CSLB Class B General Contractor's License Practice Exam

What will happen if you add sugar-water into cement?

1. It will cause massive cracking

2. It will slow hydrolysis

3. It will speed up hydrolysis

4. It will decrease the concrete strength

The correct answer is: It will slow hydrolysis

Adding sugar-water to cement affects the setting process of concrete, specifically by influencing the rate of hydrolysis, the chemical reaction between water and cement that leads to hydration and setting. When sugar is introduced to the cement mix, it interacts with the hydration process. Sugar is known to act as a retardant, prolonging the setting time and, thus, slowing down the hydrolysis reaction. This can be particularly useful in hot weather conditions where concrete may set too quickly, allowing for easier handling and better workability during the mixing and pouring phase. In addition to its retarding effect, sugar may also affect the microstructure of the concrete as it cures. This could lead to improved workability and sometimes an enhancement in final strength when used correctly. Therefore, the correct assertion is that adding sugar-water slows down the hydrolysis process, allowing for a more controlled setting and curing of the cement. Other options, such as causing cracking or speeding up hydrolysis, do not accurately reflect the role of sugar in cement hydration. Sugar generally does not decrease strength when used appropriately, so it is important to measure and apply it correctly in concrete applications.