we poured a small 8*26 *4″ slab this am, 10:00. it was 68 and breezy. pump was used with a 5 slump. site was on south side of garage. pour went well. jiterbugged. floated. finished. at 1:00 jim called me over to see-(rebar grid was 2′ oc) a hairline crack over most of the rebar in the 8′ direction and none over the bar in the 26’direction.. he sprayed the surface and retroweled. slab looks good now.but whats with the cracks? thanks. paul.
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I will bet that the 8' rebar was laid on top of the 26' bar.
#4 rebar?
How tall were the rebar chairs? Should have used 1" chairs.
SamT
the different of temp from rebar to concrete cause a shrinkage crack. In other word rebar was a little close to surface.
you are right. the 8' bar is on top. we used 1 1/2 dobies. 1" it will be nest time. thanx. paul