California Department of Transportation
 

Contract 10-0S4504

The responses to bidder's inquiries, unless incorporated into a formal addendem to the contract, are not a part of the contract and are provided for the bidder's convenience only. In some instances, the question and answer may represent a summary of the matters discussed rather than a word-for-word recitation. The availability or use of information provided in the responses to bidder's inquiries is not to be construed in any way as a waiver of the provisions of Section 2-1.03 of the Standard Specifications or any other provision of the contract, the plans, Standard Specifications or Special Provisions, nor to excuse the contractor from full compliance with those contract requirements. Bidders are cautioned that subsequent responses or contract addenda may affect or vary a response previously given.

Q1) Data Cores are required for this project. Data cores are defined as the completed HMA pavement, underlying base, and subbase material. The term stabilized and unstabilized materials are used to define materials that may be encountered beneath the HMA pavement section:

1) Are the base and subbase materials considered stabilized material?
2) Are the materials beneath the base and subbase materials considered unstabilized material?
3) Are any non HMA materials that fall apart in the coring operations considered unstabilized material and not subject to recovery?

Depth of cores:
1) Is coring required until you reach the interface between the subgrade and base/subbase material?
2) Are all non HMA materials above the subgrade material subject identification and thickness measurement?

Type of material:
1) Are CTB, base coarse and subbase coarse acceptable definitions for the type of material encountered beneath the HMA section?

Sequence of Data Coring operations
1) The contract requires cores to be obtained “after all paving is complete”. Is this a reference to the entire project or the top lift of HMA within a section of the roadway requiring a Data Core?

Core hole backfill material
1) What type of material is considered acceptable to backfill the stabilized and unstabilized portion of core holes?
2) Are cutback and HMA asphalt acceptable backfill materials for the HMA portion of core holes?

Payment
1) This is a lump sum bid item, at what point will payment be made to the Contractor for completed work?

A1) Regarding stabilized and unstabilized materials, 1. Per the special provisions for Data Cores, "Each core must include the stabilized materials encountered." Stabilized materials would be materials that have been treated with cement, lime, or asphalt binder to "stabilize" them and should be brought up as part of a core. If they are no longer intact, they would be considered "unstabilized" or "failed". These materials will most likely be in the base. 2. Yes. 3. Per the special provisions, "You may choose not to recover unstabilized material but you must identify the material." Regarding depth of cores, 1. Yes. Per the special provisions, "Each core must include the stabilized materials encountered." 2. As much as it is possible without auguring, the contractor is expected to identify unstabilized material and relative thickness. Per the special provisions, "You may choose not to recover unstabilized material but you must identify the material." Regarding type of material, It is anticipated that the person coring and sampling will identify the materials as best they can. "CTB", "aggregate base" and descriptions of other types of materials will be determined by the sampler. Regarding sequence of data coring operations, Per the special provisions, "Take data cores that include the completed HMA pavement." When the contractor chooses to take the cores is to be determined by the contractor - immediately after paving is complete, or any time before the project is completed. Regarding core hole backfill material, 1. Per the special provisions, "submit proposed methods and materials for backfilling data core holes" for the Engineer's approval. 2. Per the special provisions, "submit proposed methods and materials for backfilling data core holes" for the Engineer's approval. Regarding payment, Typically, a percentage of the lump sum price is paid as work progresses. The contractor should discuss this with the Engineer in the prepaving conference.


Q2) Would Caltrans entertain the idea of using Type B HMA in the intersections instead of RHMA Gap Graded?

A2) Please bid per contract bid document.