Question: Are air-entraining admixtures necessary to produce frost-resistant roller-compacted concrete pavement (RCC)?
Answer: The Pavements section of the Portland Cement Association's Web site (www.cement.org/pavements) has lots of good information about RCC mix design and construction. They answer this question as follows: Air-entrainment of RCC traditionally has had only limited application. Most of the problem comes from the difficulty of entraining a good air-void system in such a low-paste, low-moisture concrete. Field performance over many years in harsh climates has shown that RCC performs very well in freeze-thaw environments without the use of air-entraining admixtures. Minimizing frost damage in RCC has been accomplished by proportioning mixtures with sufficiently low water-cementitious material ratios so that the permeability of the paste is low. The use of proper compaction techniques that lower the entrapped air-void content, increase strength, and lower the permeability of the concrete will also improve the pavement's frost resistance