Q.: What can a finisher do to control or eliminate chert popouts?

A.: There is probably nothing that can be done in the finishing operations to affect the number of popouts from the presence of chert particles. The only way to eliminate such popouts is to see that chert particles are not present in the mix— which may mean the substitution of another aggregate or an expensive process of aggregate beneficiation—or else to use a topping over the surface made with a concrete that does not contain chert.