Road Update: Piping And Blasting

Here is an update on Amherst roadwork from DPW Director Bruce Berry:

Lyndeborough Road Update

One of the most important lessons in road construction / reconstruction is removing water from the road base by giving it a controlled place to go. Lyndeborough Road was built over ledge. Water sheets over ledge, and in some places the ledge is less then a foot below the asphalt. When water saturates the road base, the freeze thaw cycle does its job, Mother Nature does her work, and the road falls apart. This probably explains why some of the same sections of Lyndeborough Road were repaved (overlayed) in 1987, 1989, 1994, 2000, and my skim coat west of Winding Hollow in 2007.

Except for the knoll near Winding Hollow (whose removal is to improve visibility) most of our efforts have been to redirect water away from the road base by installing underdrain piping and stone, four feet below finish grade. Until we excavate the ditch for underdrain and expose the rock, it is difficult to anticipate the extent or ledge density. Some sections such as down by the hiking trail are shale type rock and can be broken with a hydraulic hammer (attached to the excavator). Other places like up near Carol Ann, the rock is so dense, hammering is ineffective and unproductive. Unfortunately, to open a sufficiently sized trench, these areas require blasting. I hope the above explanation clarifies why we are still blasting beyond my initial time estimate. 

We hope to complete any remaining blasting West of Carol Ann either on Monday or Tuesday. That will reduce the West Work Zone (Carol Ann – Candlewood) to just the pipe crew, who will be in that area all week (except the holiday). 

The East Work Zone (Amherst Street – Winding Hollow) will pick up where it left off as soon as the drill rig can be moved back. As a heads up, soon after the knoll has been completely blasted, the road will be closed (for the removal of the rock chucks) to all traffic for probably 48 hours. I will attempt to give a two day warning prior to that happening, and the sign boards will be changed to reflect the closure.

Seaverns Bridge Road Update

Scheduling is everything, the cleanup machine for driveways and shoulder work came in today, may be moved out on Monday and be back again Tuesday. You have all been very patient about the driveways. We hope to have a bunch prepped and a hand paving crew in sometime next week, but with a midweek holiday that could change. I will do my best to push this.