# Question re road paving **URL:** \ **Category:** Factual Questions\ **Created:** [November 14, 2016, 6:48pm UTC](https://boards.straightdope.com/t/question-re-road-paving/771980 "2016-11-14T18:48:56Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![Dingbang](https://avatars.discourse-cdn.com/v4/letter/d/ac8455/32.png) [@Dingbang](https://boards.straightdope.com/u/Dingbang)\ **Post date:** [November 14, 2016, 6:48pm UTC](https://boards.straightdope.com/t/question-re-road-paving/771980/1 "2016-11-14T18:48:56Z")
The street leading to my neighborhood has been undergoing a complete resurfacing for a few weeks now. They did lots of prep work, put down a new black top, and finally painted the lines. Everything was put back together and it was lovely when they left. But then about a week later they came back and shut down the entire road for most of the day so a truck could slowly spray sand on the road. This was not a sanding truck like the city would use for ice or snow, but more like a water truck with nozzles on a bar across the rear. It sprayed a rather fine sand, a substantial amount that accumulated on the road and remained for days. As far as I could tell, that’s all they did, just put the sand down and that’s it. What’s the purpose of the sanding? ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [November 14, 2016, 7:29pm UTC](https://boards.straightdope.com/t/question-re-road-paving/771980/2 "2016-11-14T19:29:02Z")
I found this blurb from the Nation Forest Service [“Asphalt Seal-Coat Treatments”](http://www.fs.fed.us/eng/pubs/html/99771201/99771201.htm) … it talks about a wide variety of asphalt seals including sand. In a nut shell" > [@](#): > > Asphalt seal-coat treatments are mainly a preventive maintenance procedure applied to the asphalt pavement surface to prevent or delay costly corrective measures (figure 2). Asphalt seal coats are surface treatments designed to seal and protect the asphalt pavement from harmful environmental conditions such as sunlight, rain, and snow. Surface treatments are also applied to enhance the wearing properties and improve the traction between the pavement and vehicle tires. > > Asphalt seal-coat treatments are surface treatments that will not cure problems beneath the pavement such as a base failure or deterioration of the material beneath the asphalt pavement. Surface treatments work well where the distresses are limited to pavement surface deterioration, or where cracks are not severe. The seal coat limits water from infiltrating through the pavement into the underlying material. … and specifically … > [@](#): > > Sand Seal > A sand seal is a sprayed application of asphalt emulsion followed by a covering of clean sand or fine aggregate (figure 4). A pneumatic-tire roller is often used after applying the sand. Excess sand is removed from the road surface after rolling. > > Sand seals enrich weathered pavements and fills fine cracks in the pavement surface. The sand can provide additional skid resistance to the pavement while also inhibiting raveling. > > As in fog seals, emulsions with rejuvenating properties can be used. The additional expense of the rejuvenating emulsion could be cost effective if there are many small cracks in the pavement. CRF Restorative Seal of Witco Corporation and GSB-88 of Asphalt Systems, Inc. are products that are designed to penetrate and restore aged pavements. > > Advantages > The sand seal generally provides a thicker coating on the pavement surface than the fog seal, resulting in a longer life expectancy. The sand seal on polished aggregate surfaces can provide additional skid resistance. > > Disadvantages > Only fine cracks are filled and larger cracks tend to reappear within a year. ---
**Author:** ![GeorgiaEvertonian](https://avatars.discourse-cdn.com/v4/letter/g/71c47a/32.png) [@GeorgiaEvertonian](https://boards.straightdope.com/u/GeorgiaEvertonian)\ **Post date:** [November 15, 2016, 12:50am UTC](https://boards.straightdope.com/t/question-re-road-paving/771980/3 "2016-11-15T00:50:36Z")
> [@Dingbang](#): > > The street leading to my neighborhood has been undergoing a complete resurfacing for a few weeks now. They did lots of prep work, put down a new black top, and finally painted the lines. Everything was put back together and it was lovely when they left. But then about a week later they came back and shut down the entire road for most of the day so a truck could slowly spray sand on the road. This was not a sanding truck like the city would use for ice or snow, but more like a water truck with nozzles on a bar across the rear. It sprayed a rather fine sand, a substantial amount that accumulated on the road and remained for days. As far as I could tell, that’s all they did, just put the sand down and that’s it. > What’s the purpose of the sanding? did the sand stay on the road? I am assuming it did not given the time lapse between asphalt placement and the sand treatment. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [November 15, 2016, 1:25am UTC](https://boards.straightdope.com/t/question-re-road-paving/771980/4 "2016-11-15T01:25:13Z")
Well … it sure could … asphalt is just goop and aggregate … it would still be fresh and pliable in a week … it’s not like concrete that sets up like rock … the sand packs down into the goop and forms a protective seal over the top of the road … I’ve seen along California farm roads them just squirting goop down and covering it with 1/4" minus … let the traffic pack it all together … ---
**Author:** ![GeorgiaEvertonian](https://avatars.discourse-cdn.com/v4/letter/g/71c47a/32.png) [@GeorgiaEvertonian](https://boards.straightdope.com/u/GeorgiaEvertonian)\ **Post date:** [November 15, 2016, 1:36am UTC](https://boards.straightdope.com/t/question-re-road-paving/771980/5 "2016-11-15T01:36:49Z")
yes, but at least in my experience, the sand/stone treatment is done within 48 hours, that is why i was asking him/her how much of the sand remained on the road ---
**Author:** ![Dingbang](https://avatars.discourse-cdn.com/v4/letter/d/ac8455/32.png) [@Dingbang](https://boards.straightdope.com/u/Dingbang)\ **Post date:** [November 15, 2016, 2:58pm UTC](https://boards.straightdope.com/t/question-re-road-paving/771980/6 "2016-11-15T14:58:28Z")
It was visible on the road for at least a few days. Loose and shifting with the passing cars. Maybe that was just the excess and the point was to pack some into the fresh asphalt, but it had been about a week since they finished striping the road and much longer since the asphalt went down. Maybe three weeks. ---
**Author:** ![watchwolf49](https://avatars.discourse-cdn.com/v4/letter/w/e9c0ed/32.png) [@watchwolf49](https://boards.straightdope.com/u/watchwolf49)\ **Post date:** [November 15, 2016, 6:15pm UTC](https://boards.straightdope.com/t/question-re-road-paving/771980/7 "2016-11-15T18:15:29Z")
> [@GeorgiaEvertonian](#): > > yes, but at least in my experience, the sand/stone treatment is done within 48 hours, that is why i was asking him/her how much of the sand remained on the road I agree, it should be done right away to be correct … maybe they noticed afterward the 100 yard pile of sand …