Topics Covered in This Issue Include s3
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SUPERPAVE Digest 27
Topics covered in this issue include:
15) Are you running PP5? by "Kenneth Hobson"
Date: Fri, 29 Aug 97 08:57:08 +0600 From: "Kenneth Hobson"
AASHTO PP5 contains a separation test for Type I Polymers. I was wondering if others are running this test.
Have you had any Type I polymers fail this test?
Have you compared this with a similar test that uses 4 degree F difference in softening points as the failure criteria? This is called OHD-L-41 at OKDOT.
------Work email: [email protected] Home email: [email protected] Home Page: http://www.telepath.com/khobson Wpwin Tips: http://www.telepath.com/khobson/listserv.html Work Phone: 405-521-2677 Work Fax 405-522-0552 ------
Date: Wed, 10 Sep 1997 11:13:00 -0500 From: [email protected] To: [email protected] Subject: FW: Are you running PP5?
I am forwarding a response from Gayle King, Koch Materials Company.
RESPONSE The cigar (toothpaste) tube PMAC separation test with a maximum softening point difference of 4 F was required in the task group 31 specifications for Type I (SBS) modified asphalts and ultimately adopted by a number of AASHTO DOT's. The test originated in Germany, with a maximum R&B softening point difference of 2 C between top and bottom thirds of the tube after oven storage. This test is quite useful for identifying incompatible polymer systems which are prone to separation in asphalt storage tanks. When this requirement is met, contractors should not need agitators in their modified asphalt tanks. When no separation requirements were included in specifications, we have seen SBS modified asphalt delivered to jobsites that had over 60 F difference in R&B softening points in the cigar tube test. With the advent of SHRP, the R&B softening point was dropped in favor of the Dynamic Shear Rheometer as the measurement of consistency (PP-5). The original proposed difference in stiffness (G*/sin delta) between top and bottom samples from the cigar tube was originally limited to plus or minus 5%. Since this limit is below the accepted reproducibility of the DSR measurement itself, most organizations have increased the acceptable difference to 10%, which is still quite severe. This test is now under review by NCHRP research project 9-10. (Hussain Bahia is PI).
------Phil Blankenship Koch Materials Company PO Box 1875 Wichita, KS 67201 Voice (316) 828-8495 Fax (316) 828-7385 [email protected] ------From: Kenneth Hobson To: Superpave Listserve Subject: Are you running PP5? Date: Thursday, August 28, 1997 9:57PM
AASHTO PP5 contains a separation test for Type I Polymers. I was wondering if others are running this test.
Have you had any Type I polymers fail this test?
Have you compared this with a similar test that uses 4 degree F difference in softening points as the failure criteria? This is called OHD-L-41 at OKDOT.
------Work email: [email protected] Home email: [email protected] Home Page: http://www.telepath.com/khobson Wpwin Tips: http://www.telepath.com/khobson/listserv.html Work Phone: 405-521-2677 Work Fax 405-522-0552
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