I did mine 10 years ago with Toupret Fill-Flex. It took several applications because it shrinks but it's been stable and solid since.
Should add that I'm usually dealing with painted brick so it's easier to cover the differences in materials.
@Airhead started
London Fixed Gear and Single-Speed is a community of fixed gear and single-speed cyclists.
I did mine 10 years ago with Toupret Fill-Flex. It took several applications because it shrinks but it's been stable and solid since.
Should add that I'm usually dealing with painted brick so it's easier to cover the differences in materials.