May 1985 Table of Contents

Features Milwaukee Prevents Pavement Scaling

About 50 years ago it was discovered that concrete with entrained air was remarkably more durable when exposed to freezing and thawing than was concrete without air. Read more

Features Whitetopping an Asphalt Parking Area

Potholes, birdbaths, cracks, ruts and loose gravel are nuisances and often hazards for users of many asphalt parking lots. By "whitetopping" a deteriorated "blacktop" pavement, the owner can make the lot do what it should--provide clean, safe and convenient parking for customers and employees. Read more

Features Composite Floor System Combines Concrete Slab and Open Web Joists

Open web steel joists support a reinforced concrete slab--typically 2 1/2 to 3 1/2 inches thick--while it is hardening; then the two act together to resist live loads on the structure. Read more

Features Pavement Rehabilitation with Portland Cement Concrete

Pavements are wearing out faster than they can be repaired. The Federal Aid Highway Act recognized this in 1976 by permitting the use of federal money to rehabilitate pavements to extend their useful life. That law broadened the definition of construction to include resurfacing, restoration, and rehabilitation, thus introducing the term 3 Rs to the jargon of the transportation agencies. Since then, growing attention to replacement has added a fourth R and recycling may well make a fifth. Read more

Problem Clinic Fly Ash in Shotcrete and Bond of Finish Coat

A swimming pool contractor who is a customer of ours wants an oversanded mix to use in shotcreting. We have suggested one of our oversanded mixes which contains 730 pounds of cement, 180 pounds of fly ash, 700 pounds of 1/2-inch stone, and 1800 pounds of sand. Read more

Problem Clinic Don't Bushhammer Gunite Substrate

We're required to remove, clean up and replace gunite that we recently applied to cover a concrete wall surface that was spalling. We had faithfully followed specifications and took special care with the bushhammering of the old surface to be sure that it Read more

Problem Clinic Sparkling Aggregate for Flatwork

While visiting downtown San Francisco recently, we noticed that the concrete sidewalks appeared to have a sparkly substance in them. We really like this effect. Can you help us identify the substance and tell us how it can be made available to us? Is this Read more

Problem Clinic Chloride Limit on Post-Tensioning Cable in Duct

Is there a limitation on chloride ions in concrete if the post-tensioning steel is located in ducts and will be encased in grease? Isn't that adequate protection for the steel? Read more

Problem Clinic Porous Flatwork

Where did I see information about slabs made of concrete that is porous enough for water to drain straight down through it? Read more

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