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Archive for September, 2006
I beam bridge hanger
Posted by John on September 27, 2006
I am pouring a slab over job and an older concrete man showed me his garage and how he used a bridge hanger to support the 2X6 waler and 2X6 joists and plywood. The 8in 35 lb I beam will support the hanger. I have found companies that carry these but they are expensive. He said he rented the unit and returned the case hardened bolts and the crossmember obviously stayed within the slab. Is renting these a thing of the past? John Enders
This is a question that should be referred to your local construction products distributor. I am not familiar with the concrete practice you describe. Usually construction hardware can be purchased from a distributor. They would also have access to the manufacturer of the product you are looking for. Good luck on your project.
Quality of Concrete Work
Posted by Mark on September 26, 2006
Our driveway and garage was re-concreted a few weeks ago. The contractor already said he will re-do the driveway approach, because he put plastic on the concrete, which left numerous swirls and discoloration. Now the garage has several cracks, and the finish has several big dark discolorations. I’m worried about the cracks appearing and growing so quickly. The contractor said he will make a saw cut in the garage, which should prevent further cracking. He said the cracks are normal and has not offered to re-do the job. But I wonder if the garage needs to be re-done. I question the quality of the work. What do you think?
I understand your concern about the cracks in your garage, however, it is important to find out the reason for the cracks development.
In general it is a natural thing for concrete to crack.
The cracks that appear soon after the concrete is poured are most likely drying shrinkage cracks and are to be expected. If the cracks are, in fact, drying shrinkage there are a few things that can be done to minimize the possibility of cracking.
1) Use of concrete admixtures such as water reducers to lower the water cement ratio or use of shrinkage reducing admixture is recommended.
2) Addition of concrete fibers or reinforcement steel also reduces the possibility of shrinkage.
3) Proper curing is a must although it is very often forgotten.
4) Placement of control joints is always recommended. Control joints can be sealed afterwards with construction sealants to prevent the moisture and water penetration, which can cause problems especially during winter months.
Cracks developed due to drying shrinkage usually pose no structural threat even though they may be unsightly.
Another consideration is the possibility of sub-grade movement. If the cracks continue to get wider there may be movement of the base. If this is the case then saw cutting will do no good at this point. The only recommendation would be sub-grade stabilization. Removing and replacing the concrete is always an option but you may end up with the same cracks if this is not done.
If you decide to re-pour the garage, and you verify that cracks are not caused by sub-grade movements, I would suggest control joints to accommodate the drying shrinkage. It won’t stop the concrete from cracking but the cracks will be straight.
More information regarding the control of cracking in concrete structures can be found at ACI manual section 224R – 01.
color additives in concrete
Posted by Lee on September 20, 2006
I would like to know where to find info
on different colors for concrete walks and driveways?
Color pigments which are used in produce colored concrete products are generally available in liquid, powder or granulated form. You will find all the related information about the use of colors in concrete products on the color suppliers website or on the technical data sheets of their products.
Refer to the below weblink.
http://www.concreteproductsbuyersguide.com/Block__Landscape__Paver_Products_6175ea62.html
On the page of the web link, click on either “granulated”, “liquid” or “powdered” and it would give you the list of companies supplying colors in those forms.
Now, refer to the website of these companies and you should find all the information related to the use of colors in concrete like dosage rate, way of mixing, types of colors, packaging, precautions etc. To find the company website you can type the name of the company in Google.com.
Thanks and good luck.
Foam concrete
Posted by Fazz on September 10, 2006
Hi, My name is Fazz. I have new technology of the Foam Concrete. It is light material for construction. This concrete keeps warm and cool, doesn’t mold, strong enough (depends what is density). My question how can I start produce this this concrete? How can I protect my idea? Please provide me the stage of legalisation of my new idea.
Dear Fazz,
All your questions and concerns regarding the patent procedure can be answered by the United States Patent and Trademark Office. This office has all necessary information listed on their web site: http://www.uspto.gov/go/pac/doc/general/
There you will be able to find all the information needed for a successful patent process.
Without exact knowledge of your technology, before you do so, I would suggest you look up some more information about cellular concrete or lightweight concrete, as these products can be similar to your application.
In regards to production you will be required to meet certain criteria for this type of material such as strength, fire or health necessities. These and other testing requirements can be found at IBC (International Building Code), UBC (Uniformity Building Code) or you can find specifications in ASTM (American Society for Testing and Materials Standards). www.astm.org.
add color to concrete
Posted by Harold on September 8, 2006
I am re-doing parts of a stone patio laid in concrete. What can I use to color the concrete to be near the color of the existing weathered mix.
The question of matching existing color in concrete is difficult. If you match the existing color in time the new application will fade and be different. If you use the same color that was used in the original application you would have to wait for the new color to fade to be the same as existing color.
On a small job like a patio I would suggest the use of a concrete stain. With a stain you could apply it to both new and old concrete and have a fairly uniform color.
For large jobs a colorimeter could be used to match existing color but that would take a special order to manufacture. That would mean a commitment for a quantity large enough to justify a special production run. I don’t think a patio would be big enough.
If you wanted to place a topping concrete mix over the entire area and apply a dry shake colored floor hardener you could get uniform color. Or, an integral color could be put in a concrete overlay.
Other than topping I think a concrete stain would be your best bet.
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