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Re: Concrete Overlays

[Subject Prev][Subject Next][Thread Prev][Thread Next] Given the slope of the ramp and it's large size, a polymer modified patching material that can be screeded and troweled is probably the most practical choice. Most of these materials need to be extended with larger aggregate when thickness exceeds 1" (producing a polymer modified concrete).
Given its industrial use and damp services conditions, providing an epoxy bonding agent is a must.
Personally, I would take care to study the compatibility between the shrinkage and flexural characteristics of the overlay material as compared to the substrate concrete.

Steven A.
Los Angeles
 

GSKWY(--nospam--at)aol.com wrote:

I am looking for some ideas/recommendations for a concrete overlay on a
loading dock ramp.

The ramp is approximately 30 years old, approximately 100 ft long, is fairly
steep and was built with  lightweight aggregate (expanded shale).  A lot of
the aggregate has deteriorated, particularly at the top of the ramp where
there is a lot of torque from the front wheels of the trucks.  There has also
been erosion due to run-off.  Large sections of the ramp now resemble an
English muffin.

I am thinking about removing the top 3/4 in. of the slab and replacing it
with an overlay.  The options I am considering are:  latex modified concrete
(styrene butadiene), epoxy-modified concrete or a mix with silica fume.

One consideration is waterproofing - part of the ramp is in a semi-enclosed
area with very high (>100%) humidity.  Another consideration is minimum
thickness,  we cannot remove very much of the existing slab since there are
post-tensioning cables in the longitudinal direction.

Any ideas about relative advantages/disadvantages of these three systems
would be appreciated.  Relative costs would also be somewhat of interest but
are less of an issue than durability.

Thanks,

Gail Kelley