November 1983 Table of Contents

Features Rail Systems Using Concrete Crossties

It was on a roadbed with concrete ties that the French TGV high speed train established a world record of 237 « miles per hour in 1981. Read more

Features Epoxy-Coated Reinforcing Bars

Reinforced concrete is inherently a durable and nearly maintenance-free construction material under normal conditions. Read more

Features Keeping Voids from Hiding in Plastic Concrete

It was imperative that the concrete in the tower of a cable stay concrete bridge under construction have a minimum compressive strength of 6000 psi and be free of entrapped air voids. Read more

Features Residential Concrete Floor: The Thermal Solution

The thermal mass needed in passive solar homes such as this one in Naperville, Illinois, calls for concrete. Read more

Problem Clinic Concrete on Blacktop

Our company is renovating a blacktop warehouse floor. The new floor may be used for lift truck traffic. We would like to place about 3 inches of concrete over the existing blacktop but there is grease on some parts of the surface. Would the grease harm the concrete? Should we use welded wire fabric? Read more

Problem Clinic Too Much Air

A new slab on grade in a parking garage was found to have 12 percent entrained air, rather than the 6 percent that had been specified. We don't question the accuracy of the air test but we want to know how this air content will affect the strength, durabi Read more

Problem Clinic Proportioning Mixes With Class C Fly Ash

A new source of Class C fly ash is available. Would we use the same amount as the Class F that we have been using? Read more

Problem Clinic Local Aggregate Unsuitable for Fire Endurance

For a job in New Mexico we must site-cast some double-tees. The coarse aggregate in the area contains 61 percent free silica but the Underwriters Laboratories permits no more than 20 percent free silica for fire endurance. Is there any way to treat the ag Read more

Problem Clinic Earth-Shelter Designing

We're intrigued with building an earth-sheltered home to save energy. But we've had enough troubles in the past with a slightly buckled basement wall and with basement dampness so that we wonder how to avoid these and possibly other problems. Can you give Read more

Problem Clinic Cure Shotcrete Thoroughly

Some unusual job scheduling is going to require us to apply shotcrete in three layers applied several days apart. We know we'd better not cure the first two layers with curing compound since it would probably interfere with bond. Is covering with polyethy Read more

Problem Clinic Too Much Heat

I have been asked to repair an area of about 10 feet by 10 feet in a 6-inch-thick floor on grade. This floor, in a building used by an oven manufacturer, had performed well for 15 years. Recently the company tested out a new experimental oven. I believe t Read more

Close X