obtaining concrete cores
obtaining concrete cores
(OP)
ASTM C-42 5.2 Core Drilling—A core specimen shall be drilled perpendicular to the surface and not near formed joints or obvious edges of a unit of deposit.
Suppose you have a 36"x36" column poured from the foundation to the bottom of the first level. Is it acceptable to takes cores from the top of column vertically?
Suppose you have a 36"x36" column poured from the foundation to the bottom of the first level. Is it acceptable to takes cores from the top of column vertically?






RE: obtaining concrete cores
RE: obtaining concrete cores
In the past we just anchored the drill to a finished surface and overdrilled the depth. We then snapped off the core sample and took it back in for preparation and breaking. There may be some question whether the top inch or two of a column is really represntative of the rest of the column. - undoubtedly less real consolidation due to surface effects.
I do not remember how much we overdrilled, but the break was very near the botton and was usually almost perpendicular to the axis of the drill. It just took some sawing to get a satisfactory sample.
Did the concrete possibly freeze?
With a column, your biggest challenge will be getting a sample without reinforcement of ties. - It may take a xouple of tries unless you can locate the steel in advance.
RE: obtaining concrete cores
RE: obtaining concrete cores
RE: obtaining concrete cores
if you're possibly looking for voids, try sonic testing since it's non destructive. in my opinion, windsor probe is pointless for checking either strength or voids in a column. at best, windsor probe is only suitable for slab areas where you have lots of probe tests and then it should be correlated back to actual field core compressive strength tests. after the correlation, then you might have an idea of where bad concrete might exist within the slab area. windsor probe appears too hoaky to actually evaluate strength...i think it should remain as an index test only. that's my opinion for what it's worth...and i believe aci has similar opinions on the matter even though i do not know where to find the reference.
RE: obtaining concrete cores
RE: obtaining concrete cores
201.1 Guide for Making a Condition Survey on Concrete in Service
364.1 Guide for Evaluation of Concrete Structures Prior to Rehabilitation.
437R Strength Evaluation of Existing Concrete Buildings
546R Concrete Repair Guide
RE: obtaining concrete cores
RE: obtaining concrete cores
RE: obtaining concrete cores
It's probably the best place to core if one wants to avoid the rebar, but probably the least representative for a strength sample.
RE: obtaining concrete cores
The option is non-destructive procedures and interpret the results.
Dick