Recent studies of non-metallic fiber reinforced concrete (NMFRC) indicate that this material has the potential to be used in thin-bonded overlay applications with reduced surface preparations and structural repairs. Although underlying distresses may result in cracks in the NMFRC thin-bonded overlay, the materials ability to maintain its structural integrity after cracking could permit reduced surface preparations and structural repairs. The enhanced NMFRC properties could also allow overlays that are thinner than conventional bonded overlays with equal or longer service lives. FRC may also reduce spalling even in concrete with quartzite aggregate that has a higher thermal coefficient than other aggregate types. Furthermore, 3Ms polyolefin fibers have advantages over steel fibers in that they are chemically resistant and have a lower corrosive potential.
Several problems must be addressed before this materials use is accepted. The constructability and economic impacts of using these fibers must be determined in order to support its continued use. Design criteria must be established. Methods for determining thin-bonded overlay thickness and joint spacing must be developed. The effectiveness of bond, load transfer, and the behavior of jointed and unjointed slabs should be evaluated.
Favorable performance of the relatively small NMFRC test sections and the approved recommendations of SD94-04, suggest that SDDOT should pursue construction of a thin-bonded overlay test section which will exhibit full-scale behavior using a fiber addition rate of 15 kg/m3 (25 lbs/yd3).