November 1973 Table of Contents

Problem Clinic Vapor Barriers

We have had a number of experiences in our area that indicate the use of a vapor barrier may not be advisable. The water in a concrete slab placed on a va por barrier has nowhere to go but to the top of the slab. Considerable cracking has resulted, which Read more

Problem Clinic Dowels

What is a sure way to prevent dowels from sticking ? Read more

Problem Clinic Wear Resistance

Why do some floors wear so much better than others ? Read more

Problem Clinic Laborers effect on finishing

Recently, the quality of our floors suddenly went down when we got a whole new crew of laborers. Our regular finishers seemed to be working harder than usual but the floors they built were not up to standard. What could be wrong? Read more

Problem Clinic Remixing the Gravel

What is the best way to remix the gravel that has separated out of the concrete during placing? Read more

Problem Clinic Segregation and Bleeding

How can we overcome troubles with segregation and bleeding when we use lightweight aggregate concrete? Read more

Problem Clinic Aggregate Size for Floors

What is the largest aggregate you can use in a concrete floor? Read more

Problem Clinic Aggregate Amounts

Should there be any adjustments in aggregate proportions for concretes with low slumps? Read more

Problem Clinic Don't Overuse the Darby

Why do we seem to have more trouble finishing lightweight aggregate concrete even though we take special care with darbying and bull floating? Read more

Problem Clinic Floating Lightweight Aggregate

Why does lightweight aggregate concrete become so rough during the floating process? Read more

Problem Clinic Floating and Troweling

Is it acceptable for the finishers to use both the float and the steel trowel on an area before moving to the next one? Read more

Problem Clinic A Broken in Trowel

What is the extra value of a trowel that has been broken in ? Read more

Problem Clinic Hard Steel Troweled Surfaces

Are there any disadvantages to a hard steel troweled surface? Read more

Problem Clinic Waiting to Finish

I have been placing quite a few concrete floors that are scored in 32-inch squares. These are hand troweled. When completely cured they are waxed. The number of finishers required is becoming prohibitive. The finishers stand for about four hours until the Read more

Problem Clinic Cracking

How are crazing cracks prevented? Read more

Problem Clinic Control Joints in Structural Slabs?

Why are control joints used in slabs on grade but not on structural floors? Read more

Problem Clinic Saw Blade Selection

What kind of saw blade works better for sawing joints diamond or abrasive? Read more

Problem Clinic Aggregate Effect on Sawing Joints

We have found sawing to be far too expensive to justify its use. It is a slow process and blades wear rapidly. Does aggregate hardness have some effect? Read more

Problem Clinic Choosing An Abrasive Blade

There are a number of abrasive blades available for cutting concrete. How does one choose the right blade for concrete floors? Read more

Problem Clinic Curing

Are there any advantages between clear, white or black sheet curing membranes? Read more

Problem Clinic Seal Out Water Vapor
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