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Which dry density to use?Density of cement or MDD of subbase materials

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defg

Structural
Joined
Jul 7, 2006
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Ihave got some urguments between my colleques.We are dealing with stabilzaton works for C1-stabilised subbase.After analysing the laboratory trial tests revaled that 3%of cement is adequate.Now on my case Iwant to make field trial test of 100m length and my road is 9.8m wide and the thickness of the stabilised subbase is to be 200mm.
I carryout the following arithmetics in order to know how much tonnes of cement I'm going to use in this 100m legth.
Volume of soil =100x9.8x0.20=196cum
Weight of soil=196x1910kg/cum=374.36tonnes(1910kg/cum is MDD of the subbase material)
Cement used on site=3%x374.360=11.23tons.
Our main urgument here is that my colleaqe are using density of cement instead density of subbase material!!Who is correct?As the density of cement is do high compared to MDD of subbase material!!3120kg/cum>1910kg/cum this makes the Contractor to use more cement than required!!But the Consultant claim that this is appropriate way to use the density of cement!!!Please assist.
 
Since this is a pavement/geotech issue, I suggest you try your question over at the Civil Engineering other topics or similar forum.

That being said, I think it should be 3% by weight of the cement/subbase mixture.

This not just a cost issue. If you use too much cement, you will get block cracking as the stabilized material shrinks as it cures, as my department learned several years ago, much to its chagrin.

"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928

"I'm searching for the questions, so my answers will make sense." - Stephen Brust

 
Mix design of cement modified soil is by weight/weight.
 
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