The original questions was whether a decorative and skid-resistant surface could be achieved by sandblasting a floor. I responded that sandblasting does not create suitable skid resistance for a sloped concrete surface. It also damages the surface of exterior concrete making it more susceptible to deterioration. If you want a sand blast look, I would recommend coming back with a sealer using some skid resistant additive.
Victor Klemaske responded: I have to disagree. A medium sandblast finish can achieve the required 0.8 coefficient of friction required on ramps. The aggregates that get exposed are several times harder than cement and will make an extremely durable wear surface. It is also a permanent solution, unlike the sealer with additives. Today’s low solids sealers break down faster and do not hold the skid-resistant additives as well as they used to. If they are not constantly maintained, you open up your client to risk.
Another comment, from Tony: You may be correct but the aggregate is the issue. It must be of the correct size and be of the correct angular finish to help achieve the slip resistance level. If not, the concrete will become smooth from use in a short time. Sandblasting will damage the surface of exterior concrete making it more susceptible to deterioration, but by applying a suitable coating, longer life can be obtained. End result, it is easier to re-coat than to replace damaged concrete. Use a SlipAlert unit to check the slip resistance on a gradient.
Note that the topic of the Concrete Polishing Luncheon & Forum at the World of Concrete, February 3, 2015 is slip resistance. Click here for more information on the luncheon.