November 1978 Table of Contents

Problem Clinic Avoiding Puddles on Parking Decks

In building concrete parking decks should we call for close tolerances on degree of planeness to prevent puddles? We want to do all we can to keep salt water from standing on the floors. Read more

Problem Clinic Nothing Like a Thermometer to Give Temperatures

We are required to maintain the concrete temperature of a slab at no lower than 50 degrees F during the curing period. We expect to take care of this by curing blankets, but how can we be sure we have enough covering if we get an unexpected drastic drop i Read more

Problem Clinic Safe Time to Strip a Slab

We have built a 9 1/2-inch thick concrete roof spanning 18 feet over a garage, using a 6 1/2-bag mix at 2- to 3-inch slump. The concrete is now 8 days old. How soon would it be safe to strip the forms? Read more

Problem Clinic Cracking in Waffle Floor

What could account for the cracking in a waffle floor slab that occurred just before the concrete hardened? The cracks follow the web pattern and we find that they occurred where the section changes in thickness. Read more

Problem Clinic Guidance on Use of Epoxies With Concrete

Where can I get some reliable help in choosing and using epoxies? I've learned that even though these materials are strong they don't always work--either because the wrong epoxy was chosen, or it wasn't used properly. Read more

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