April 1985 Table of Contents

Features Flowing Concrete Produced at the Batch Plant

Superplasticizers have been used for several years now to produce high-slump flowing concrete without adding excess water. Read more

Features Fly Ash

What are typical proportions of portland cement and fly ash for a concrete containing fly ash? And what are the typical cost savings when a fly ash mix is compared with a non-fly ash concrete having the same strength? First we have to differentiate between the two types of ash available. Read more

Features How Microsilica Improves Concrete

Microsilica is a mineral admixture composed of very fine solid glassy spheres of silicon dioxide. Most microsilica particles are less than 1 micron (0.00004 inch) in diameter, generally 50 to 100 times finer than average cement or fly ash particles. Read more

Features Water Reducers

Water-reducing admixtures have a fluidifying effect on concrete that reduces the amount of water needed for ease in placement. Read more

Features Nonchloride Accelerating Admixtures

A growing number of people in the industry have become aware that chlorides in concrete, in combination with water and atmospheric oxygen, can accelerate the rate of corrosion of steel such as reinforcing bars, steel decks and steel frames that are in contact with the concrete. Read more

Features Urethane Anti-Graffiti Coating Protects Concrete Soundwalls

Officials of the town of Norwalk, California, in an effort to combat the eyesores created by graffiti vandals, have specified a durable, urethane-based anti-graffiti coating system to protect 12-foot-tall concrete soundwalls that buffer noise pollution along sections of the Santa Ana Freeway. Read more

Features Test Kit for Analyzing Water or Detecting Rebar Corrosion

Concrete in land-fill areas, in former swamps and marshes, in areas near the ocean and even concrete sprayed by sprinklers used to water shrubbery can be saturated with water that contains salts harmful to it. Read more

Features Air-Entraining Admixtures: Inexpensive Insurance Against Damage Caused by Freezing and Thawing

Air-entrained concrete is more resistant to disintegration and scaling caused by freezing and thawing cycles and by the application of deicing salts. Read more

Features Soggy Site? Don't Wait -- Pave with Concrete

After the snow melts and while the spring rains keep coming, lots of owners and contractors get fidgety, waiting for a site to dry up enough to put in a parking lot. Read more

Problem Clinic Plugging of Pump Line

On our first pumping job we had unending trouble with the pump. We got very low output and every little while we would have a blocked line. We were pumping about 500 feet horizontally, using a mix that had consistently worked well for other pumpers in our Read more

Problem Clinic Detecting Superplasticizer in Concrete

Is there any way to tell, after the concrete has hardened, whether a superplasticizer was added to the concrete? Is there a way to tell how much? How about the water-cement ratio? Read more

Problem Clinic How Accelerators Protect Against Freezing

I've been having an argument. My friend says calcium chloride is added to concrete as an antifreeze. I say it's added to help the concrete gain strength faster so it can have a better chance to survive if it freezes the first night. Am I right? Read more

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