Electrical Duct Banks
Posted by REN from SAN JOSE, CA, US on March 14, 2007
Who makes Fluidized thermal backfills ( low thermal resistivity) for electrical duct banks in the San Francisco Bay area?
I am sorry I do not know who supplies such materials in San Francisco. If there is any organization/associations which represents such materials you can contact them for local suppliers.
You can try to look for this information using a search engine like google. Search "Fluidized thermal backfill" or "Electrical duct banks + San Francisco" etc and you might be lucky.
Good luck.
Foam Concrete 1
Posted by Moti from Kuwait, OT, KW on March 13, 2007
Is there any minimum thickness requirement for Foam Concrete. If there is, how much is it? If the thickness of foam concrete is about 25 to 30 cm, please advise if any reinforcement is required.
Foam concrete can be used for many different applications. The specifications for foam concrete would be project specific and depend on the purpose for which it is used.
Also, you might have to contact a structural engineer if you want to know if any reinforcement is required or not for your foam concrete application.
use of Sika admixtures for SCCin the precast concrete industry
Posted by Adrian Mircea from Cluj-Napoca, OT, RO on March 12, 2007
Hallo Bruce,
We are going to start an experimental program to introduce SCC in Romanian precast concrete industry.I saw information regarding the use of Sika-Visco Crete 5000and 6000, and recently 2100 in U.S.
Our colleague from Nederlands reccomended the use of Sika Visco Crete -20 Gold as admixture in combination with Sika Fume HR as Type II powder addition and these two could be supplied to our University by Sika Romania.
1)Could you send to me the technical prospects for these products?
2)What’s your opininion regarding the the proposed combination
( Sika Fume& Visco Crete -20 Gold )?Best regards,
Professor Adrian IOANI
Technical University of Cluj-Napoca(Romania)
Dear Professor Adrian,
“Sika Viscocrete” is the generic name of Sika’s high range water reducers based on polycarboxylate technology worldwide. However, admixtures in different countries have different names, as their formulations are adjusted for local cements and other materials.
Sika Viscocrete 20 Gold seems like a polycarboxylate admixture for the precast industry and Sika Fume HR a silica fume product. I do not have much information on these products as they are not supplied in United States.
I would recommend you to contact either the Technical services department or the Marketing department of Sika Romania. You can discus with them the objectives of your study and I am sure they would be in a better position to recommend the right product to you.
The weblink of Sika Romania and contact information is as below.
http://www.sika.ro/index.htm
http://www.sika.ro/contact.htm
Thanks
cement make
Posted by Tania from Bournemout, OT, GB on March 10, 2007
what type of cement is used for block paving production
Generally, Ordinary Portland cement (Type 1). They some times replace a part of cement using supplementary cementitious materials like Fly ash. Some cement companies still produce a type III cement. Also some companies produce a Type IB block cement. Both type III and Type IB are a finer grind and develop earlier compressive strengths.
Additives for grout
Posted by D from London, OT, GB on March 10, 2007
Hi Bruce
I have a question about the use of additives with grouts designed for deep grout curtains or consolidation grouting in dam foundations. The grout curtains are to reduce permeability under a dam and reduce water losses. Often at site the contractor orders significant quantities of additives for concrete and is therefore reluctant to order special addtives for grouts, claiming that they are anyway suitable. Which classes of additives are suitable for grouts? Typically a grout mix would be w/c 0.5 up to 1, with or without bentonite, occasionally with sand where high takes need to be stopped.
I have another question about the use of additives with bentonite slurry (typically 1-2% of cement). Are there any additives that are designed to work with bentonite?
Many thanks
To reduce permeability in concrete and grout mixes, addition of supplementary cementitious materials like Silica Fume and Fly ash should help. I would also recommend the use of a water reducer or a high range water reducer to reduce the amount of mix water and make the mixture more impermeable.
I don’t have much information on additives for bentonite. Try to do a search for that in “Google”.
