April 1977 Table of Contents

Problem Clinic Claims for Unexpected Costs

Is there any way to be compensated for extra construction costs which were no fault of our own but which were necessitated by conditions that neither the architect nor we could foresee? Read more

Problem Clinic Avoiding Air Entrapment

The article titled "Can We Get Rid of Bugholes?" (Concrete Construction, June 1972, page 266) discusses how to get rid of most or all of the entrapped air when casting walls. Is there anything that can be done to cut down on the amount of air entrapped in Read more

Problem Clinic Decoding Welded Wire Fabric Designations

What's happened to the good old designations for wire mesh, such as 4X4 10X10? I used to be able to understand this 4 inches by 4 inches, 10 gage by 10 gage. Now I keep bumping into fancy numbers like 4X4 W1.4XW1.4. Why make everything so complicated? Read more

Problem Clinic High Air Content for Easy Consolidation

Can you make concrete for a wall workable enough by means of a large amount of air so that it will flow easily, consolidate well without vibration and still have the 3000-psi strength needed? We would be willing to use as much cement as necessary. Read more

Problem Clinic Need for Cement Finishers

Please tell me if there will be need for more cement finishers in the future or fewer. Read more

Problem Clinic When to Finish a Shrinkage-Compensating Cement Concrete Slab

Finishers were puzzled when they began to float a slab made with shrinkage-compensating cement. Although the bleed water had left, the concrete seemed soft and not ready for floating. They had to wait awhile before floating. How do you know when it's time Read more

Problem Clinic Reducing Spalling From Fasteners

The most efficient way of putting in a large number of fasteners on a current job seems to be to use a powder-actuated tool. However, this method has caused a lot of spalling and so we either have to relocate many fasteners or be satisfied with a smaller Read more

Problem Clinic Measuring Moisture in Hardened Concrete

I am interested in obtaining an instrument with which I could quickly and easily read the amount of moisture in a concrete slab. Would you be aware of any firm that manufactures such an instrument? Read more

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