October 1977 Table of Contents

Problem Clinic Protect New Floor Against Salamander Gases

Is there any way to protect a new slab from the exhaust gases from a salamander without venting the salamander? We know about the dangers of carbonation of the concrete surface but we'd like not to waste so much heat. Read more

Problem Clinic Economical Street Rehabilitation

I am on the village council and have been advocating repair of our concrete streets with concrete overlays. We have a limited budget and I am not sure that bids for concrete would always be cheaper than blacktop, which has been traditionally used. What mi Read more

Problem Clinic Prestressed, Pretensioned and Post-Tensioned Concrete

What are the differences between prestressed, pretensioned and post-tensioned concrete? Read more

Problem Clinic Expansion Joints in Sidewalks

We know the general principle that contraction joints in sidewalks should be cut at intervals that make individual panels approximately square. How frequently should an expansion joint be provided? Read more

Problem Clinic Glossy Concrete Surfaces

We are achieving some nice effects with plastic form liners that produce glossy decorative surfaces on parts of a lobby wall. We would like to do the same thing in an outdoor mall but have been told that the surfaces will not remain glossy if they are exp Read more

Problem Clinic Vapor Barriers and Shrinkage Cracking

A slab was cast on a dry subgrade without any vapor barrier and we are beginning to detect shrinkage cracks. How much more cracking can we expect than if a vapor barrier had been used? Read more

Problem Clinic Preventing Deicer Scaling

Besides using a satisfactory air content in concrete what else will help minimize damage to flatwork from application of deicer salts? Read more

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