May 1977 Table of Contents

Problem Clinic No Immunity to Freezing

Is it true that concrete will no longer freeze after it reaches 500 psi and, if so, what is the best method for field-testing the concrete to determine when it reaches 500 psi? Read more

Problem Clinic Dowels Should All Run the Same Way

A recently constructed parking lot is cracking already. Dowels were carefully installed in both directions but the cracks seem to be associated with the dowels. What could be wrong? Read more

Problem Clinic Take Out Pavement Ruts By Grinding

Ruts have been worn in a main concrete street in our town by studded tires. The city is planning to resurface with asphalt to restore the smoothness and get rid of the puddles and ice that collect. Resurfacing with concrete would be better but the city se Read more

Problem Clinic Lightweight Coarse Aggregate Floats

The coarse aggregate particles in a lightweight-aggregate mix are giving trouble by floating to the top of the lift during vibration. This shows up as a difference in surface texture along horizontal lift lines after the forms are stripped. The aggregate Read more

Problem Clinic Sampling Pumped Concrete

One person says one thing about where to sample the concrete to make test cylinders of pumped concrete and another says something else. Is it correct to sample from the truck chute or the end of the pump line? Read more

Problem Clinic Forming Circular Openings in Floors

What is the best way to form circular openings for pipes to pass through floors and how do you anchor such form materials so they stay in place and remain vertical? Read more

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