August 1987 Table of Contents

Features No More Strained Backs

Any construction job will be made easier with the help of a crane. But, you have to match the crane and bucket with the jobsite conditions. A crane that can only lift a half-full bucket of concrete or can't reach the entire concrete pour area kills your budget and schedule. To match the crane to the job, you must plan carefully by choosing the right crane boom length, crane size, and layout. Read more

Features Tower-Mounted Concrete Placer Keeps Buildings on Schedule

Perforated concrete perimeter walls for a 42-story office tower were built using climbing wall forms. Read more

Features Contractor's Crews Learn Fast on Superflat Job

Skeptics say it's nearly impossible to build a superflat floor when a dry shake floor hardener is also specified. Read more

Features Thirty-Three Risers Formed All at Once

Risers at the Charlotte Coliseum were built in 2 1/2 months using three-piece forms that cast a complete pie-shaped section of the arena in one placement. Read more

Features The Many Types of Concrete Retaining Walls

Traditional cast-in-place concrete retaining walls are fast becoming untraditional. Read more

Features Conveyor Systems Solve Concrete Placing Problems

On large volume concrete pours, contractors can often combine different types of conveyors to solve concrete placing problems. Multiconveyor systems can place concrete at rates greater than 200 cubic yards per hour. Read more

Features Florida Bridge Builder Beats Summer Heat with Liquid Nitrogen

During Florida summers, the concrete temperature drops in some Florida Rock Industries ready mix trucks. Read more

Features Water, Water, Everywhere. . . and Concrete Durability Problems

Nine times out of ten the culprit which causes poor concrete durability is water. Read more

Features New Features for Mixer-Mounted Conveyors

On some small to medium jobs, the truck chute falls short and there's not enough concrete to justify pumping costs. Read more

Features Pumping a Large Foundation Mat

The cost of pumping concrete for a large building foundation mat can be minimized in several ways: Read more

Problem Clinic Causes of Slump Variation

What can cause a wide variation in mixing water needed to get a uniform slump for ready mixed concrete? For a 4-inch slump, I normally need to batch about 150 gallons of water in a 5-yard load. Sometimes, though, it takes as much as 170 gallons to get the Read more

Problem Clinic 1/2 Plus 1/2 Doesn't Equal 1

We're going to be paving a parking lot that is 90 by 220 feet. The plans call for a 1/2 percent slope in both the east-west and north-south directions. I told the owner's representative that to avoid birdbaths the minimum slope should be 1 percent (1/8 in Read more

Problem Clinic Does Silica Fume Darken Concrete?

Some of the concrete in a project we'll be building will contain silica fume (microsilica) as an admixture. Read more

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