September 1981 Table of Contents

Features Why Concrete Columns Can Crack

Investigators of cracking problems in concrete structures have from time to time noticed horizontal and vertical cracks in concrete columns. Read more

Features How to Minimize Cracking and Increase Strength of Slabs on Grade

A major cracking problem that joint control will not solve, plastic cracking (also referred to as plastic shrinkage cracking) is cracking that occurs in the surface of fresh concrete soon after it is placed and while it is still plastic. Read more

Features International Development with Second Generation Lift Slab

Conventional lift slab construction is a method of casting all floors of a building at ground level, then jacking them into final position on the building's columns. Read more

Features Cracks in Concrete: Part I

Cracks rarely affect the structural action or the durability of concrete significantly, but they look bad and they let water in more easily and thus may accelerate weathering or rusting in some cases. Read more

Features Cracks in Concrete: Part II

How can we prevent cracking, or at least keep it down to acceptable levels? Read more

Problem Clinic High School Science Project

I am a ninth grade student and for my science project I have decided to research the subject of concrete. My father has received your magazine for years and I hope you may be of assistance in my project. I would appreciate some information about concrete Read more

Problem Clinic Nonprejudicial Subcontract Forms

In an earlier issue I read an article about contract forms for subcontractors to use in making up their one-contract terms pertaining to the work they propose to perform on a prime contractor's job. Where can I get such forms? Read more

Problem Clinic Residential Design on a Florida Key

I plan to build a house on one of the Florida keys. The code requires the house to be built 8 feet above the waterline, so new houses are built on stilts. What literature or guidance can you give me on the proper steel to put in concrete pilings and in th Read more

Problem Clinic Exposing Aggregate on Treads And Risers

In exposing aggregate on both the treads and risers of concrete steps, can I use a retarder on the forms? Read more

Problem Clinic Thick Slabs Curl Less

We've had many recommendations on how to minimize curling of concrete floors--mostly recommendations about mix proportions, improving the possibility of moisture escaping from the bottom of the slab, and shortening the joint spacing. Read more

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