Concrete Construction Online Magazine: Surface Issues

What's Hot?

Fri, 16 Dec 2011 01:31:05 EST

How do I know when to use hot weather concreteing techniques?

Fog Spraying and Concrete Strength

Fri, 16 Dec 2011 01:30:45 EST

If we fog spray flatwork to help prevent shrinkage cracking, is there any danger of increasing the water-cement ratio at the surface and reducing the strength of the concrete?

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?

SCC in Tilt-Up Applications

Sun, 12 Dec 2010 08:50:17 EST

Q: Can self-consolidating concrete be used for tilt-up panels? What does the finish look like, and are plastic shrinkage cracks a problem?

Biting the Dust

Sun, 12 Dec 2010 08:34:01 EST

The owner of a recently constructed manufacturing facility contacted us to help solve a problem with the concrete floor's surface.

Proper Prep Before Work Starts

Thu, 16 Dec 2010 01:21:14 EST

I'm relatively new to the concrete polishing business. My company has been involved in treating stone and tile floors for years, and recently began to polish more concrete surfaces. Recently, we were asked to bid on a project that featured a concrete floo

Fixing a Curling Floor

Sun, 12 Dec 2010 08:40:42 EST

The contractor says it is a workmanship problem between me and the excavator. What are your thoughts on this and how should I go about repairing it? The contractor suggested pumping grout under the floor at the joints, but I don't think that is a good ide

The Relevance of Microcracking

Sun, 12 Dec 2010 08:55:54 EST

What is microcracking? As a small concrete contractor, should I be concerned about it?

Grinding Questions From a Novice

Tue, 5 Jun 2012 05:06:47 EST

I am the building manager for a large church on the East Coast. We recently have contracted with a company to grind and overlay about 5000 square feet of our church.

Did Salt Finish Affect Color?

Mon, 13 Dec 2010 10:16:36 EST

I am the building manager for a large church on the East Coast. We recently have contracted with a company to grind and overlay about 5000 square feet of our church.

Problem Clinic: Why Does Concrete Discolor?

Tue, 21 Dec 2010 01:56:35 EST

Why does concrete discolor even though the specifications (wet cure) were followed without exception?

Birdbaths

Tue, 21 Dec 2010 01:54:22 EST

I am bidding on treating a concrete slab and one of the specified requirements is that there not be any birdbaths. The final surface will be flooded to see if this has been achieved. Do you have any suggestions?

Re-entrant Corner Problems

Tue, 21 Dec 2010 01:56:00 EST

We recently were called to apply an epoxy surface to a newly constructed 6-inch-thick warehouse slab with a tight 12x12-foot sawcut control joint pattern. Can you explain what may have caused these random cracks to develop?

On the Questionable, and Perhaps Lost, Art of Curing Concrete

Sun, 12 Dec 2010 08:46:59 EST

I have a project specification that requires fog spraying, followed by curing compound, followed by wet cure with burlap and soaker hoses. Why the complicated curing requirements? Isn't this a case of specification-overkill?

Cold-Weather Cracking

Sun, 12 Dec 2010 08:36:07 EST

We have had a number of slabs placed in our area lately that are experiencing severe surface cracking. Our finisher says it's the concrete's (and therefore the ready-mix producer's) fault. The ready-mix producer says it is a result of failure to follow appropriate cold-weather concreting techniques. What's really going on?

Flooring over concrete

Mon, 13 Dec 2010 10:16:39 EST

Although I've been lucky so far and have not had to deal with a failure of flooring materials applied over one of my slabs, it scares me to death thinking about it. What can I do to keep this problem from occurring?

Concrete expansion joints

Mon, 13 Dec 2010 10:16:18 EST

I was told that what we used to call expansion joints I should now call contraction joints. Does that mean that concrete doesn't expand?

Decorative Problem Clinic

Sun, 12 Dec 2010 08:38:33 EST

We are installing colored textured concrete in an enclosed mall being constructed in a winter climate. The general contractor is using temporary unvented construction heaters that put both the heat and the exhaust into the enclosure. When we came back the following day I noticed that some of the color was “dusting” off the surface of our work. Why is this happening and what should we do?

From Shrinkage to Shadowing

Tue, 21 Dec 2010 01:53:49 EST

We've been asked to bid on a polishing project on a recently placed slab. The engineer had been concerned about controlling concrete drying shrinkage. He developed a concrete mix design optimization plan that resolved many of the problems that occur on industrial slabs on ground. The slab has performed very well, but this surface has many dark spots on the hard-troweled surface. What are these spots?

Cracked Curb

Fri, 10 Dec 2010 06:22:53 EST

We are experiencing intermittent shrinkage cracking while placing extruded concrete curb. Generally the cracking occurs along the face of the curb and the presence of tight radii does not seem to make much difference. What can we do to stop this?