Many of the problems in flatwork and paving arise within that critical period after placing and before final finishing. This article answers questions on blisters, jointing, pulling and tearing of the surface, rain damage, the setting time being either too fast or too slow, setting with bleed water present, and having a sticky surface. Blistering occurs when a fresh concrete surface is sealed airtight at a time when air voids are migrating to the surface. The air collects under the airtight surface and creates blisters. Several conditions may contribute to their formation. One is wind blowing over the concrete surface, reducing its moisture content. Another is a subgrade that is cooler then the concrete so that the top surface sits faster than the bottom. A sticky mixture containing excessive fines also contributes to sealing of the surface and blistering. Lean mixes can add to the problem because they may have to be worked excessively to produce the desired finish and the extra work may seal the surface. Finishing too early and the misuse are making an excessive number of passes with a vibrating screed, excessive use of the jitterbug, excessive use of the bull float or using a power float with the blade not flat. Slabs on ground require control joints to permit horizontal movement without random cracking. Control joints are permissible because of the subgrade support. In structural slabs it is necessary for the concrete to be continuous between supports, thus making it impossible to use control joints. Here cracking is distributed uniformly and unobjectionably by the distribution of the reinforcing steel. Pulling and tearing the surface can be a problem when using air-entrained concrete. Aluminum or magnesium floats should be used on air-entrained concrete because this type of metal float greatly reduces the amount of work required by the finisher. A wood float tends to drag along the surface of air-entrained concrete, makes it more difficult to finish, and tends to tear the surface.