Concrete Construction Online Magazine: Most Popular

Nominal Weight of Standard Concrete

Tue, 5 Jun 2012 05:06:03 EST

What's the nominal weight of standard concrete?

Sweating Slab Syndrome

Tue, 21 Dec 2010 01:54:10 EST

What is sweating slab syndrome and how can it be prevented?

Skin burns from concrete

Fri, 7 Jan 2011 05:25:35 EST

Why will concrete severely burn the skin? Years ago I ended up with third degree burns on my legs, though prior to that I had concrete on my legs many times and never was burned. I know that there are several concrete burn cases a year at most hospitals, but it is still not a common occurrence in the trade. When I warn people who are working with concrete they reply that they have had concrete all over them and never have been burned. Do concrete batches vary enough to make some concrete more caustic? What components in concrete cause it to act as a lye and give third-degree chemical burns? I would appreciate an answer on this, and feel that it would be valuable information to pass on to others in the concrete industry.

Prestressed, pretensioned and post-tensioned concrete

Thu, 9 Dec 2010 09:07:09 EST

What are the differences between prestressed, pretensioned and post-tensioned concrete?

Cold joints

Tue, 5 Jun 2012 05:09:59 EST

What is meant by the common term 'cold joint?"

R-Value of Concrete

Mon, 13 Dec 2010 02:48:56 EST

What is the R-value of a typical 8-inch-thick, cast-in-place, residential basement wall?

Rain's Effect on Fresh Concrete

Fri, 10 Dec 2010 06:06:17 EST

We had a concrete patio placed. About 3 hours after it was placed, it began to rain and continued to rain for 2 hours. Will that compromise the integrity of the concrete with respect to strength, durability, and so on, over the long term?

Moisture Problems with Concrete Slabs

Tue, 21 Dec 2010 01:54:46 EST

Why does it seem that moisture-related flooring problems are more common today than in the past?

What's a 1:2:4 Mix?

Thu, 9 Dec 2010 04:21:12 EST

I have a residential-concrete specification that calls for a 1:2:4 concrete mix. What does that mean?

Asbestos and Old Concrete

Mon, 1 Oct 2012 06:05:58 EST

Asbestos was used in concrete products in the past and could pose a threat in some instances.

Waterproofing Concrete Storm Shelters

Tue, 5 Jun 2012 05:21:49 EST

We build concrete shelters for farmers who want protection from tornados. The shelters have a 10x10-foot footprint and walls are 7 feet high. We cast the floor slab first, leaving a keyway at the edges, then cast the walls and roof in one pour. The shelte

Concrete topping

Wed, 8 Dec 2010 04:00:47 EST

Please tell me how to correctly prepare and apply a concrete topping. We recently placed a slab, and then topped it with a mixture of 1 part cement and 3 parts sand. The slab was given a broom finish before the topping was applied. We did not use a bonding agent between the slab and the topping. After the topping had been placed, we were caught in a rain storm and the topping now is sandy and loose. What do you suggest?

Bonded Versus Unbonded Concrete Overlays

Wed, 15 May 2013 11:56:58 EST

Which type of concrete overlay is better depends mostly on the condition of the existing pavement.

Removing Urine Odor from Concrete

Fri, 16 Dec 2011 01:35:59 EST

Our cat frequently urinated on our basement concrete floor, which now has a strong urine smell. I’m in the process of getting the house ready for sale and have tried everything I can think of to remov

Concrete Expansion Joints

Wed, 15 Dec 2010 03:14:24 EST

Are joints in concrete meant to accommodate expansion or contraction? Someone told me that what I've always called expansion joints I should now call contraction joints. Does this mean that concrete doesn't expand? What are these joints actually supposed to do?

Does Concrete Expand?

Thu, 9 Dec 2010 04:21:18 EST

I attended a seminar at which a speaker said that concrete doesn't expand. I told him I've always read that concrete expands when the temperature rises or when the moisture content increases. The speaker held his ground, however, and said that concrete doesn't expand. Is my literature outdated?

Concrete finishes

Tue, 5 Jun 2012 05:08:57 EST

Concrete finishes are sometimes described by means of the letter F followed by a number. When are the various finishes called for and how are they produced?

Expansion Joints Not Needed in Sidewalk

Thu, 9 Dec 2010 04:15:24 EST

I have been contracted to build 2,000 linear feet of 5-foot-wide, 4-inch-thick sidewalk on a 4-inch gravel base. The specifications call for expansion joints every 20 feet. I contend that expansion joints are needed at a minimum of every 50 feet and where the walk will abut existing structures. Control joints will be cut every 5 feet. Am I right in suggesting expansion joints every 50 feet?

Recommended Floor Slope and Tolerance

Thu, 9 Dec 2010 04:24:13 EST

We're designing the concrete floor for an auto dealership's service department.

Effect of Concrete Strength and Slab Thickness on Floor Strength

Fri, 10 Dec 2010 05:59:51 EST

The specification for the floor of a maintenance building called for a 6-inch slab thickness and concrete with a design compressive strength of 3000 psi. The actual average cylinder strength for the floor concrete was 3630 psi. Four months after the floor