The subgrade shall be shaped to the sections, lines and grades shown on the plans, prior to applying lime.
A.
Lime may only be spread on areas where the mixing operations will be completed on the same working day. The application and mixing of lime with the material shall be accomplished by either “Dry Placing” or “Slurry Placing”. Hydrated lime that has been exposed to open air for six (6) hours or more or to excessive loss due to washing or blowing will not be accepted for payment.
1.
Dry Placing.
Spreading of the lime shall be accomplished by an approved spreader or by bag distribution at the rates specified on the plans. The lime shall be distributed at a uniform rate and in such a way as to minimize the scattering by wind. No application of lime shall occur when the wind conditions are in such a manner that blowing lime becomes objectionable to traffic and adjacent property owners. Quick lime may be spread by approved distributor or by motorized grader to achieve uniform distribution. The material shall be sprinkled with approved water until the proper moisture content has been established.
2.
Slurry Placing.
The lime shall be mixed with approved water in approved distributor trucks and distributed as a thin water suspension or slurry. The required rate of lime distribution shall be achieved by successive passes over a measured area until the proper lime content and moisture have been obtained. On steep slopes, prevent runoff of slurry.
B.
Mixing.
The subgrade material, lime and approved water shall be thoroughly mixed and blended by an approved pulverizing mixer to the depth specified on the plans. Mixing shall proceed until a homogenous, friable mixture is obtained such that after removal of non-slaking material, 100 percent of the material passes the 1-3/4" sieve and a minimum of 85 percent passes the 3/4" sieve. If Type C - Grade DS Quicklime is used, moist cure the material for two (2) to seven (7) days and remix to the above required gradation.
C.
Compaction.
The mixture shall be compacted after final mixing and not later than three (3) calendar days after final mixing unless approved by the Engineer or the designated representative of the Engineer. The material shall be aerated or sprinkled with approved water as necessary in order to achieve optimum moisture. If the total thickness of the material cannot be mixed in one mixing, then the previously mixed material shall be bladed to a windrow from the area to be treated and the lime mixing for the next layer will begin. The first layer of treated material shall not be mixed with the underlying material. Compaction of the mixture shall begin at the bottom and continue for the entire depth until a uniform compaction to not less than 95% of Standard Proctor Density from 0% to 3% above optimum moisture content as determined by ASTM D-698 is achieved or to the density shown on the plans.
D.
Finishing, Curing and Preparation for Surfacing.
After the final layer or course of subbase or base has been compacted, it shall be brought to the required lines and grades in compliance with the typical sections. Completed sections shall be finished and rolled with a pneumatic roller or other suitable roller light enough to prevent hair cracking. Moist curing for the completed section shall be a minimum of seven (7) days before any other course is placed or traffic is permitted unless otherwise approved by the Engineer or the designated representative of the Engineer. Moist curing shall be accomplished by sprinkling with water to prevent the surface from drying out or by addition of an asphalt material to retain moisture in the subbase or base. Layers on which the subbase sets up sufficiently to prevent unacceptable damage from traffic, may be opened up to traffic two (2) days after completion. If treated material is required to be sealed or covered by other courses of material, then such seal or course shall be applied within fourteen (14) days after compaction unless otherwise directed by the Engineer or the designated representative of the Engineer.
(Ordinance 2007-106, App. B, adopted 3/20/07)
The course surface shall be maintained in a smooth condition, free from ruts and undulations, until it is accepted and/or another course is laid. If the material should lose the required stability, density and finish for any reason, before the work is accepted or the next course is placed, then it shall be recompacted and refinished at the expense of the Contractor.
(Ordinance 2007-106, App. B, adopted 3/20/07)
Allow access to completed portions of work for field density testing by the Owner using the nuclear method. Contractor shall pay for failed tests and Owner will pay for passing tests.
(Ordinance 2007-106, App. B, adopted 3/20/07)