Road Construction In Land Development
It’s a HAPPY DAY when road construction begins, ‘cause there’s nothing like moving dirt!
With the proper permits in place, it’s time for action.
Key Elements of Road Construction:
The transition from drawings to earthwork brings the dream of a finished project that much closer for any land developer. Whether it’s concrete, asphalt or a gravel road, the structural integrity is directly tied to the preparation of the native soil and the sub-grade. Of course the goal of any road improvement is to create a driving surface that transmits the load stresses so that the load limits of the road are not exceeded. When the load bearing capacity is over stressed you wind up with surface treatment failure and a damaged subgrade. That means big bucks to fix, so do it right the first time!
Pavement types:
Asphalt is the treatment of choice with most residential land developers, however it’s useful to understand that there are two commonly used methods of paving. The first is rigid pavement which uses concrete (Portland Cement) and the second is flexible pavement where asphalt is an example. Concrete can be continuous, jointed in sections, or reinforced internally and is usually placed directly on the properly prepared sub-grade. Sometimes an additional layer of stabilized material is needed between the subgrade and concrete overlay depending on geotechnical and load conditions.
Asphalt
That’s one of my project roads. Note the center crown and the negative slope gradient down to the white fog line.
Asphalt - a flexible pavement:
Unlike concrete, where the integrity of the road relies on the flexural strength of the slab to protect the subgrade, asphalt distributes the wheel load stresses down and dimensionally outward to the sub-grade so that you get even distribution of the pressure stress. Asphalt is a bituminous (petroleum based) semi solid mixed with gravel or sand. There are three different types of asphalt paving, but the one I have used the most is a full-depth asphalt pavement option. This is where two separate asphalt lifts are layered on top of the fully prepared sub-grade. This method offers the best durability for high traffic roads and can help in other ways. An example would be the 2-step lift application for larger projects where I hold on the second and final lift until home construction is substantially completed in the project. The damage from heavy loads carried on construction vehicles (think cement trucks pouring pools) can be taken on the first lift and any damage patched before the final lift.
Concrete - a rigid surface:
Never used it and no need to. Concrete uses a slab approach to handle load. Thickness and resulting flexural strength provides the needed integrity and durability. You see concrete road surfaces where you expect to - freeways, large commercial projects and certain types of smaller businesses like gas station pump pads where a petroleum based treatment like asphalt would be a problem. High cost is a huge factor in the use of concrete and it is generally avoided if any other reasonable choice can be made.
Gravel Roads:
Well…here we go! Yes, I’ve done gravel roads, but just 2 times that I can remember. One was in a short plat and the other was a finger road in a larger project where neither the builder or the real estate agent thought it would be a problem. Gravel roads are what we do when the cost of hard surface treatment is not feasible due to cost. Sometimes it’s done in the rural environment because all of the other roads around the project are gravel or dirt.
My opinion is that many of my rural developer competitors rely too much on this cost saving approach to road construction. The presentation in the beginning is “ok” but gravel roads do not hold up and the ruts and washout problems just never seem to end … simply because they don’t! Plus, in my experience an asphalt road surface can be a big contributor to enhanced project market value. A cost to market value analysis should be done before deciding against an impervious asphalt surface. If a guy is going to go with a gravel or dirt road I suggest paying very close attention to creating a good Road Maintenance Agreement, and believe me - a gravel or dirt road will need to be regularly maintained.
For more see: Road Maintenance Agreements (RMA’s) https://www.landdevelopmentrealities.com/home/2020/8/11/rural-community-ccamprs-for-land-developers .
Asphalt failure
It’s not always from substandard asphalt thickness and we’ve all seen it - the cracking and rutting of asphalt roads from fatigue.
Concrete failure
This patch of concrete cracked due to settling of the sub-grade.
Causes of road failure:
The first thing that almost every guy thinks of when he sees failure of a road surface is that the paving crew scrimped on the application thickness of the material. That can happen, but if it happens to me I only have myself to blame. There is such a thing as being on-site during construction (Duh) and I always take core samples on my asphalt roads just to make sure. The other thing we think of is some idiot damaging the road with a cement truck or other super heavy load. Actually, the above photo showing asphalt failure is from a neighbor of mine that poured a pool and the damage shown was caused by a cement truck, so yes, these things happen.
Failure to prepare the subgrade:
Unlike others, the first thing I wonder about when I see road failure is how well the sub-grade was engineered and prepared. To me the sub-grade is everything since it is the literal foundation of the road. Proper geotechnical evaluation of the soil is essential along with engineering design to create a sub-grade that holds up under pressure. Proper prep and construction is also essential and I frequently use a crew that I have come to know and trust based on past projects. More about Steve, my head honcho later. Failure of the subgrade can happen when it was not properly engineered and prepared, along with improper application of the surface treatment, or sometimes both. Just remember not to be that guy and on-site presence is essential in every phase, including this one.
Regional issues affecting sub-grade:
Sometimes the regional big picture rules over good sub-grade preparation. An example is Florida where the entire state is mostly sand over limestone. We’ve all seen the pictures on TV of the giant sink hole that swallowed some guy’s house. That problem can translate to land developers on a smaller scale when structural geologic support, like cracking limestone layers fail, thus destabilizing the road above it. In other regions like the Pacific Northwest, that isn’t usually a factor, except for earthquakes. I guess no matter where you are, it’s a really smart idea for a land developer to have a good geo tech onboard!
Temperature Variance:
Land developers in extreme climates know this seasonal cause of road failure very well, but temperature variances affect roads everywhere. The slow, but constant, expanding and contracting of the road surface materials, road aprons and drainage slopes takes a toll over time, it just happens faster in certain climates.
Lastly - Construction and a tribute to Steve my “Director of Community Relations”:
A great road construction crew makes it all happen and Steve is the best guy I know. Steve has been the Top Kick of all my road construction in the Pacific Northwest and he knows everything about moving dirt. I met him on my first project and let’s just say he was a little “slow to warm up”. It didn’t have anything to do with me in particular, he was just that way. Steve taught me everything I know about road construction and site work in general and he always took the time to get the job done right. Thank you Steve!
It was only later that I found out about his background and ultimately decided to make him my Director of Community Relations! :)...
Steve was a law school graduate and passed the state bar for the sole purpose of making his family happy. Immediately afterward, he quit law before he even started and bought a backhoe and went to work in dirt for himself. Steve could be an odd duck and every once in a while he would decide he really didn’t like someone. Anyway, I had this high-end project with million-dollar views and homes to match. Of course, when you have a project like that you get one or two residents with million dollar egos along with it.
We were in between bigger work so I asked Steve to take care of some burn piles on the unfinished east side of the project and he was permitted and burning away. As HOA President I got a complaint call one day from Ron, one of my malcontent residents. He told me he had gone up to the burn piles to tell Steve he could smell the smoke and that Steve had called him an A-hole. Of course I got all the info and apologized to Ron for Steve’s attitude toward him and told him I would speak to Steve about it pronto.
In a couple of days I was on-site again and button holed Steve. He told me basically the same story as Ron and made sure to highlight what a jerk he was. I told Steve that we don’t call our residents A-holes, no matter what. He immediately stared right back at me and said “I never called him an A hole”! Well, I said, that’s what he told me. It was then that Steve got me straightened out by saying “Like I told you, I never called him an A hole, I just told him he was starting to act like an A hole”. That’s when I saw his lawyer training coming through and WOW, what a huge difference his choice in words meant … humm, not really...
After that, I always called Steve my Director of Community Relations and it became the running joke every time we had a complaint about something. Seriously though, find yourself a Steve for your road construction because good road construction crew makes all the difference in the world. Good luck.
