303CEMENT TREATED PERMEABLE BASE COURSE

303.1DESCRIPTION—This work is the construction of a cement treated permeable base course (CTPBC)

on a prepared surface. If placed on subgrade, this work includes the preparation of subgrade as specified in Section 210.

303.2MATERIAL—

restrict the material passing the No. 200 sieve to a maximum of 2%. Determine the loss by washing according to PTM No. 100. Do not use fine aggregate in the mixture. The use of blast furnace slag or crushed gravel is allowed. When using crushed gravel, provide a minimum of 75% crushed particles with at least two faces resulting from fracture.

• Submit, for review by the Representative, a mix design using 200 pounds of cement per cubic yard based on the saturated surface-dry rodded unit weight of aggregate. Fly ash may be substituted for up to 10% of the required cement, with a substitution ratio of 3.3 pound of fly ash for each 2.2 pound of cement. Design and proportion the cement and water based on the saturated surface-dry weight of the aggregate. Do not exceed a water-cement ratio of 0.40. Provide a mix with 100% coverage of aggregate without runoff. Mix and proportion as specified in Section 704.

• Certify as specified in Section 106.03(b)

303.3CONSTRUCTION—

pavement/subbase before placing CTPBC, if necessary to ensure a moist condition. Sprinkle with as much water as it readily absorbs, well in advance of CTPBC placement.

screed, plate vibrator, and fully automated sensors to control profile and transverse grade. Use mechanical equipment for the entire lane width or as much lane width as practical. Adjust screed assemblies to provide the required cross section and depth. Compact the CTPBC using steel-wheel power rollers having a manufacturer’s certified metal weight from 8 tons to 10 tons. Use of vibratory paver screed as sole means of attaining compaction is not allowed. Perform a minimum of one pass with the roller to achieve compaction and do not compact material to the point that the

CTPBC is not free draining, or the aggregate is crushed. One roller pass is defined as one trip of the roller in one direction over any one spot. Perform handwork as directed. Do not disturb the freshly placed CTPBC. Do not allow more than 1 hour from the time water is added to the aggregate and cement to the time compaction is complete. The Contractor may use a retarding admixture to increase the time to 1 1/2 hours.

and at transverse joints and paving notches. Test the surface in stages using a 10 -foot straightedge. At each stage, hold the straightedge in contact with the surface and parallel to the road centerline and, in successive positions, test the pavement surface from one side to the other. Advance the test location to the next stage by moving the straightedge along the pavement centerline by not more than 5 feet. Correct irregularities of more than 1/2 inch by loosening surface mixture and removing or adding CTPBC. For irregularities that develop after compaction is completed, correct the irregularity by a method that does not produce contaminating fines or damage the base. Do not grind or mill the CTPBC. The area is defective if irregularities or defects remain after final compaction.

compound as specified in Section 501.3(l)1.c. except apply at a rate of 1 gallon per 100 square feet ± 10% of the surface area, or as directed. As an alternative curing method, the Contractor may select to cover the CTPBC with white polyethylene sheeting material as specified in Section 501.3(l)1.a. Maintain curing materials for 24 hours. If the CTPBC temperature falls below 40F during the 24-hour curing period, extend the cure period by an additional 24 hours. At no cost to the Department, remove and replace CTPBC if the CTPBC temperature drops to 32F within 72 hours of the placement.

CTPBC for at least 3 days after the CTPBC has been placed. Do not place overlying pavement on the CTPBC during this time period. After the 3-day period, restrict construction traffic to only allow trucks and equipment required to place th e next layer or any adjacent CTPBC lift or pavement course. Remove and replace areas damaged or contaminated at no cost to the Department.

dig or drill one full-depth, test hole for each 3,000 square yards of completed CTPBC. The Representative will measure the depth of the CTPBC. Where the depth is defective, define the defective limits by digging or drilling additional test holes longitudinally and transversely until the depth meets requirements. Backfill test holes with CTPBC mixture.

depth, deficient in surface tolerance, or when the surface contains defects caused by rain or improper finish that in the Representative’s opinion cannot be repaired. Unless otherwise directed in writing by the District Executive, remove and replace defective CTPBC full depth at no additional cost to the Department. Submit a plan with proposed methods to remove and replace the CTPBC. Remove and re place the CTPBC after the plan is approved.

303.4MEASUREMENT AND PAYMENT—Square Yard