Table of Contents June 1975

FEATURES

Other Articles

• Realistic Calculations of Costs for Wall Formwork Systems

   

• How to Avoid Problems with Lightweight Mixes

   

• How to Avoid Problems with Pumping Equipment

   

• The Day the Pump Ran Dry

   

PROBLEM CLINIC

• Concrete swelling like yeast

  How do you handle concrete that swells like yeast?

   

• Metallic shake and vacuum dewatering

  Is it possible to use a metallic shake on a concrete floor that has been vacuum dewatered?

   

• Calcium chloride in flatwork

  What are the advantages or disadvantages in using calcium chloride in concrete floors or other flatwork?

   

• Spacing rebars

  How far apart must rebars normally be spaced?

   

• Vapor barrier and vacuum dewatered concrete

  Is a vapor barrier needed when concrete is vacuum dewatered?

   

• Color variation in vacuum concrete

  Does vacuum dewatering ever cause variation in color?

   

• Depth of joints in floor toppings

  What is the proper way to cut joints in floor toppings one-fifth of the thickness as in regular slabs, or all the way through the topping to the joint in the base slab?

   

• Terrazzo Thickness

  What is the normal thickness of a terrazzo floor topping?

   

• No frost allowed

  An inspector recently made us thaw the frost from the reinforcement before he would let us place the concrete. Is this necessary? We were using concrete that had been heated. Shouldn't that melt any frost on the rebars?

   

• Durability of shrinkage-compensated concretes

  We have been told that concrete made with shrinkage-compensated cement is more likely to be damaged by freezing and thawing than regular concrete. Is this so?

   

• Pavement blow ups

  How does one prevent pavement blow ups, and what can be done about them once they occur?

   

• Deflecting forms

  What can we do to keep prefabricated formwork from deflecting?