Beach Sand in Concrete
Beach Sand in Concrete
(OP)
Hi,
I have a contractor who has used some sand for mixing concrete which may have questionable levels for chlorides (sodium chloride). I believe he may have mined some sand from a near by beach. I have taken a sample of sand for testing but would appreciate thoughts on the acceptable levels of chloride in concrete. We have since stopped the contractor but now need to establish the extent of demolition.
Thanks
I have a contractor who has used some sand for mixing concrete which may have questionable levels for chlorides (sodium chloride). I believe he may have mined some sand from a near by beach. I have taken a sample of sand for testing but would appreciate thoughts on the acceptable levels of chloride in concrete. We have since stopped the contractor but now need to establish the extent of demolition.
Thanks






RE: Beach Sand in Concrete
RE: Beach Sand in Concrete
While there is historical evidence that mixing concrete with sea water has less detrimental effect than one would think, that is not particularly so with "beach sand". Chlorides tend to concentrate in the sand (from evaporation), thus increasing the chlorides in the concrete.
I would limit the amount of soluble chlorides to no more than 0.2% of the weight of cement or no more than 1 lb. of chloride per cubic yard of concrete.
RE: Beach Sand in Concrete
RE: Beach Sand in Concrete
RE: Beach Sand in Concrete
RE: Beach Sand in Concrete
I don't believe the sand was washed. I'm not overly conerned about bonding since the loads are tiny but I am more concerned about durability. We are several months behind schedule so if the chloride levels are very low say less than 0.1% we may be inclined to accept the concrete with a stern warning about future use of that type of sand. It perphas would get a bit more complicated if the the levels are on the border of what is considered acceptable by ACI.
Thanks for the responses.
RE: Beach Sand in Concrete
If you are using plain concrete and the strength is okay, you are probably fine.