base for slab-on-grade???
base for slab-on-grade???
(OP)
On the contract drawings the engineer has specified that the slab-on-grade be placed on “6 inches of granular subbase compacted to 98% of its standard proctor maximum dry density in accordance with ASTM-D698".
The spec book defines “granular subbase” as follows: “Granular subbase shall be sound and free-draining, such as sand, gravel or crushed stone with less than 10% passing the #200 sieve. Maximum diameter shall be 1-1/2.”
Is the engineer giving the contractor 3 choices for granular subbase: sand, #57 stone, or crusher-run?
The spec book also has a section on “Placement of Granular Subbase” which reads: “Compact Granular Subbase to 95 % of the maximum dry density as measured by the Standard Proctor, ASTM D698, with a water content within +3/-3 percent of the optimum moisture content.”
A proctor on #57 stone? What’s that all about? Would that be a method A, B, or C?
Should this stuff make sense to me or am I missing something?
The spec book defines “granular subbase” as follows: “Granular subbase shall be sound and free-draining, such as sand, gravel or crushed stone with less than 10% passing the #200 sieve. Maximum diameter shall be 1-1/2.”
Is the engineer giving the contractor 3 choices for granular subbase: sand, #57 stone, or crusher-run?
The spec book also has a section on “Placement of Granular Subbase” which reads: “Compact Granular Subbase to 95 % of the maximum dry density as measured by the Standard Proctor, ASTM D698, with a water content within +3/-3 percent of the optimum moisture content.”
A proctor on #57 stone? What’s that all about? Would that be a method A, B, or C?
Should this stuff make sense to me or am I missing something?






RE: base for slab-on-grade???
The way it is written, sounds like the Contractor does have three options - suggest letting the Engineer decide - could be financial consequences (Change Order).
I don't think you are missing anything. In fact you seem to have a clearer view of the situation than the Engineer - I don't think it is "written" anywhere that contract documents have to make sense - although they should.
www.SlideRuleEra.net
RE: base for slab-on-grade???
As SRE said...poor coordination of the specs.
For this, I would consider that you have an unclear requirement and you should formally request an interpretation by the Engineer or Architect of Record.