October 1982 Table of Contents

Features Chloride Content Limits Recommended by ACI Committee 201

In the late 1970s ACI Committee 201, Durability of Concrete, was finishing work on its "Guide to Durable Concrete" to update a 1962 report on the subject. Read more

Features The Chloride Scare

Some experts have concluded that chloride ions, including chlorides present in the initial mix or from seawater and road deicing salts, are responsible for corroding the reinforcing bars which, in turn, spall off the covering concrete. Read more

Features Effects in the United Kingdom of Limiting the Use of Calcium Chloride in Concrete

It was during the 1960s that the serious problem of corrosion of embedded steel in concrete became associated with the action of chlorides and in particular with the use of the accelerating admixture calcium chloride. Read more

Features Current Trends with Concrete Accelerators

Recently, Committee 212 of the American Concrete Institute (ACI) published "Admixtures for Concrete," which echoes the ACI 201 document "Guide to Durable Concrete." Read more

Features Playing the Percentages with Calcium Chloride

Percent calcium chloride, chloride ion, soluble chloride what does it all mean? Read more

Features Concrete Slab Cast on Arctic Permafrost

When a heavy equipment maintenance facility was built in Prudhoe Bay, special measures were taken to keep the frozen ground frozen. Read more

Features Readers Argue Against Severe Restrictions on Chloride Admixtures

Most natural materials contain some chlorides and I agree with ACI 201 that no calcium chloride or admixtures that contain appreciable doses of calcium chloride should be added to concrete that will be exposed to moisture and chlorides in service, as in parking garages. Read more

Features Colored Concrete Pavers -- an Architectural Complement

Used in urban renewal projects, in pedestrian plazas and malls, courtyards, sidewalks, crosswalks and even streets, colored concrete paving blocks add contour, color and charm. Read more

Features Nonchloride Accelerators: Some Case Histories

The major reasons for using accelerators are: to accelerate initial set for earlier finishing; to develop high early strength for maximum concrete production; and to minimize length of time required for winter protection. Read more

Features Who Can Settle the Chloride Controversy?

Calcium chloride, the old workhorse of winter concreting, may soon be out to pasture if some have their way. Read more

Features Corrosion -- Do Chloride Accelerators Promote It?

When engineers weigh results of numerous studies on disruption of concrete by corrosion of steel where chlorides are present, some of them conclude that calcium chloride admixtures can contribute to this serious problem. Read more

Features Pros and Cons of Chloride Limits: a Comparative Summary

Proposals for stricter limits on chlorides added to concrete mixes are being made. Read more

Features ACI Building Code Revisions Include Proposed Chloride Limits

ACI 318 "Building Code Requirements for Reinforced Concrete" is one of the most influential standards of the American Concrete Institute because it is widely adopted by local governments as part of their building codes. Read more

Problem Clinic Source of Polystyrene Beads

Your article on low density concretes, (March 1981, page 253) has stimulated our interest. We would appreciate knowing where to look or call for suppliers of expanded polystyrene beads who are at present furnishing this product in the open market. Read more

Problem Clinic Acceptable Thickness in Parking Lot

What tolerances have been established for the thickness of parking lots? We have a 5-inch pavement that averages about 0.35 inch less than specified thickness (measured by ASTM C 174). In one place the deficiency in thickness is more than 1.5 inch. Read more

Problem Clinic Structurally Sound, Waterproof Earth-Sheltered Homes

Our company is trying to develop a system for constructing earth-sheltered homes. We are particularly interested in being able to assure ourselves of structural integrity on every job and to make the buildings watertight. Do you have any suggestions? Read more

Problem Clinic Matching Vertically and Horizontally Cast Wall Surfaces

Please explain how the surface texture of a cast-in-place structural concrete wall can be made to match the surface texture of curtain walls made of precast panels. Read more

Problem Clinic Half-Round Keyways and Standardization

We manufacture wood shapes for chamfers, moldings, rustications and various special uses. Read more

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