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) The cross-sections on page 2 and 3 (X-1, X-2)show a plan thickness of 0.20 foot within the Travel Way and 0.35 foot in the shoulder. Standard Specification Section 39-1.11, par. 15 states, "For Standard and QC/QA, if 3/4-inch aggregate grading is specified, you may use a 1/2-inch aggregate grading if the specified paved thickness is from 0.15 foot to 0.20 foot thick". Since the 0.20 foot section in the Travel Way contains the vast majority of Item 18 quantity, is Standard Specification Section 39-1.11, par. 15 applicable for Item 18?
A1) Per Section 10-1.17 of the Special Provisions (page 63 of blue book): The aggregate for HMA Type A must comply with the 3/4 inch grading. 11Oct10.
Q2) Is Caltrans actually specifying PG70-16 binder for this project?
A2) Please refer to addendum No. 2 dated October 21, 2010. 22Oct10.
Q3) Cold In-place Recycling (CIR) currently requires, as specified, that the work be completed during daylight hours. This is imperative since the specification requires an emulsified recycling agent be used. The emulsified recycling agent must break, cure and set in the upper portion of the recycled layer before traffic is applied. The Project Specification recognizes this need under General, Construction that states, Do not perform CIR work unless the pavement temperature is a minimum 60 degrees F and the ambient temperature is minimum of 50 degrees F and rising. Complete all CIR work including compaction at least 30 minutes before sunset. There are no daylight working hours available for this project. Please clarify this conflict?
A3) Please refer to Addendum No. 4, dated November 5, 2010. 29Nov10.
Q4) Night time CIR-EE? The work hour will not allow this project to be built. The emulsified must break, cure and set in the upper portion of the recycled layer before traffic is applied. This will not happen at Night, in addtion the spec says Do not perform CIR work unless the pavement temperature is a minimum 60 degrees F and the ambient temperature is minimum of 50 degrees F and rising. This doenst happen at Night. The spec also says Complete all CIR work including compaction at least 30 minutes before sunset. There are no daylight working hours available for this project. Please work with traffice to get NEW WORK HOURS AND TRAFFICE CONTROLL REQUIRMENTS.
A4) Please refer to Addendum No. 4, dated November 5, 2010. 29Nov10.
Q5) Please clarify the conflict between CIR specified curing requirements and traffic closure only allowing night construction. Cold in place recycling uses an emulsified bituminous product. This product can react mechanically (meaning that it requires direct sun and heat to start the curing process) or chemically (meaning that when the emulsion comes in contact with the aggregate (RAP), it starts the curing process and allows cohesion of the asphalt to the aggregate faster than a purely mechanical break/cure.) It is important to understand that the emulsion is at least 35% water, and for that water to leave the system and be resistant to traffic loads, it requires sun and heat. The specification for this Cold in place recycling (CIR) calls to finish all CIR procedures including compaction at least 30 minutes before sunset to allow some mechanical cure and prepare the road for traffic. From laboratory studies, in order to achieve a degree of early strength, pavement temperatures need to be high (approx 80-85F for at least 2 hours). The specification for CIR also calls for not starting the work until the pavement temperatures are 50F and rising, which is expected during the day to increase and have additional UV curing effects. Night construction of CIR will only be successful if the road is closed to traffic 5-6 hours after the prescribed working hours finish at 6am. This will allow the system to eliminate the excess of water by sun and heat achieving a minimum early strength.
A5) Please refer to Addendum No. 4, dated November 5, 2010. 29Nov10.
Q6) Seeking clarification on optimum daylight conditions for construction per specification. Specification requires a temperature "raising" which is not possible in nighttime construction (termperature commonly drops between 11pm-3am). In addition, specification requires work to finalize before sunset, which is contradicted by starting after sunset in this contract.
A6) Please refer to Addendum No. 4, dated November 5, 2010. 29Nov10.