CA PRA LABE 10(1) Lava Beds Main Road Pavement Memo.pdf

Memorandum

Subject: CA LABE 10(1) Lava Beds Main Road Pavement Recommendations

Date: August 15, 2021

From: Ron Andresen Materials Engineer

To: Jim Kerrigan, PM Ryan Owen, Lead Designer

Background:

This pavement report for this project was done in January 2004. The project has since been unshelved, updating the plans and SCRs. The project will be constructed using the FP-03 metric version.

A scoping trip was made June 2-3, 2021 by Jim Kerrigan, Ryan Owen, Todd Hansen and myself. Pavement related issues were:

• To ascertain the condition of the Main Road, and the pullouts along the Main Road.

• Review the condition of the Cave Loop Road looking for any sign of distress due to the lava tubes that run underneath the roadway.

• Determine if the Hill Road at the north entrance boundary proceeding south for approximately 1 kilometer can be widened between 0.3 to 0.6 meters to match the rest of the roadway width in the park.

• Determine if it is possible to pulverize 125mm for the full length of the roadway.

Since the project was originally scoped and drilled in 2004 the roadway has received multiple surface treatments to preserve the road. The roadway has alligator cracking and shows age distress. The roadway is a perfect candidate to pulverize and repave with new Hot Asphalt Concrete Pavement. The park maintenance staff have also been removing concrete and asphalt sidewalk, curb, and gutter and replacing with new concrete. Many of the areas identified in the 2004 plans to receive new concrete have already been replaced by the park. The new project will consist of pulverizing the existing roadway and pullouts and do much less concrete replacement.

The Cave Loop Road was discussed with the Park Service June 2 prior to visiting the site. The Park Service has not noticed any cracking or other distress in the roof of the lava tubes from traffic on the roadway above. After looking at

August 15, 2021 the Cave Loop Road there was no cracks or other distresses noticed above ground to indicate any lava tube roof structure failure.

The Hill Road from the intersection with the Main Road north to the park boundary, approximately 1 kilometer, was walked measuring pavement width and roadway bench width every 17 meters. The pavement width was approximately 6 meters and the bench width was approximately 7 meters.

In the original pavement report the depth of pulverization varies between 100mm and 125mm. To simplify the work and make the project easier to bid one pulverizing depth for the entire project was desired. After reviewing the boring logs from the 2004 report, the areas identified with 100mm pulverizing has acceptable material below the 100mm depth. Pulverizing 125mm would not get into poor material.

Recommendations:

After visiting Lava Beds National Monument, discussing the project with the National Park Service personnel, and driving and walking the roads in the park, I recommend the following:

• The road be pulverized as planned in the original design. The existing pavement and chip seals should be pulverized along with the existing base to form a new base layer, and resurfaced with new Hot Asphalt Concrete Pavement.

• No special requirements are necessary when paving the Cave Loop Road.

Industry standard pulverizing and paving practices can be followed when reconstructing the Cave Loop Road. This includes pulverizing the existing pavement and base, and compacting the new pavement using a vibratory roller.

• The Hill Road bench width is currently wide enough to widen the paved surface 0.6 to 1 meter. The widening can be done without any additional disturbance.

• Pulverizing should be done to a depth of 125mm throughout the project.

This will not get into poor in-situ material and will make the work easier to bid since the depth will be the same throughout the project.

If you have any questions, please let us know.

CC: CFLHD Pavements & Materials Project Files:

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