Concreteproducts - Admixtures

Foundations
Posted by dennis from arlington, VA, US on April 16, 2007

When building foundation walls there is a technique where the cinder blocks are dry-stacked and a polymer is applied to the outside for strength and waterproofing. What is this technique called and where can I find more info on this? Thanks

Please contact the National concrete masonry association (NCMA) at www.ncma.org for this information.

thanks

drying troubles
Posted by lara from hendersonville, NC, US on April 14, 2007

Dear Bruce,

i have been working with mortars mixed with lime and different aggregates tocome up bwith my own decorative mortars

lately since I work in dry and hot conditions i have problems with the mixture

it still dries the way Iexpect it to dry

but it has no more strenght

it seems to me that the water that i am adding is evaporating to quickly so it does not allow to make a strong bond

I have understood that lime by itself holds water longer in the mixture and works as a natural plastifier

wood there be any agent available that could help me with this problem still keeping the lime in the mix

I have looked into acrylic polymers but it seems to me that they are reducing the water ratio

I hope you have the answer for my problem

regards

lara

The strength of a mortar mix primarily depends on the water to cement ratio. Also, since you are working in a hot environment, the loss in the workability of the mortar mix will be faster due to the temperature and evaporation losses.

I would recommend you to use either a water reducing and retarding admixture or a high range water reducing and retarding admixture for your purpose. These admixtures will not only enable you to reduce the amount of water needed in the mix, which will improve the strength of the mix but will also help to mix to be workable for a longer time.

concrete in saltwater
Posted by dan from new york, NY, US on April 9, 2007

are there any admixes you would recommend for a concrete pillar(roughly 3ft x 3ft by 2 ft) that will be underwater twice a day –it will be used to support a boat davit. also if salt water was used in the mixing of the concrete aggregate would it be any stronger—thank you

You can use a high range water reducing admixture, to reduce the water content of the concrete mix; this will make the concrete more impermeable. You can also add a acrylic or latex polymer to improve the water proofing property of the concrete.

I would recommend you to use regular tap water instead of sea water.

crack on rcc roof
Posted by u from motihari, OT, IN on April 3, 2007

My foor is six month old and some cracks are visible along the electric pipelines layed at the time of making roof. what should i do before the coming monsoon rains?

Generally the electric pipelines are placed on or above the steel reinforcement of the slab. So there shouldn’t be any cracks formed along the electric pipelines as it has sufficient cover.

It’s difficult to imagine the problem in your case. I would recommend you to consult an engineer or a qualified contractor to have a look at your house and see what they recommend.

Good luck.

wayerproofing a basement
Posted by robin from hailfax, NS, CA on April 3, 2007

I have a cinderblock basement that that is need of some waterproofing . The basement is bare cinder block. I would like to coat the inside with a layer of a water proof cement, then paint it. I would like to do this myself. What would you suggest I should use. I am having the foundation dug out and the drainage fixed. The outside of the basement will be coated and a plastic or rubber mebrane put on.

You can apply a polymer modified cementitious coating on the interior as well as the exterior of the wall.

Search Admixtures

Q/A Archives

April 2007

Related Experts

Sign-up for RSS

Admixtures

Archive for April, 2007