Building a foundation is an integral step to installing any road surface, but that process begins well before pouring the concrete or asphalt. It starts with proper grading and excavation. Before any road construction can begin, the site needs grading and excavation services. Without these construction techniques, the foundation of these surfaces can be ineffectual and cause a collapse, especially as wear and tear break down the road’s substrate materials.
To ensure that you build a durable roadway that will last as long as possible, you need to understand the beginning steps of the installation process. Here at Morgan Pavement, we often get asked, “What is grading and excavating?” and “How essential is site preparation?”
Being expert contractors, we understand that not everyone understands the role excavating and grading play in road construction. So, our team put together a guide to illustrate these vital services.
Let’s take a look.
What is Grading and Excavating?
Grading and excavating is the process of preparing land for roadways or structures. These services include smoothing out the soil, flattening an area, building an area up, or sloping it to a certain degree, depending on the site requirements.
Even unpaved roads require excavation and grading services to rejuvenate the road surface and eliminate problems like corrugation and potholes. Grading and excavating contractors provide excavating and grading services to clear, dig, and level the site before laying any concrete or asphalt.
Excavating focuses on removing any materials and obstacles in the area to change the shape of the site. If there are any tree stumps, boulders, or debris, an excavating contractor will remove these materials and transport them to an appropriate area using specialized equipment. These machines also dig holes and build dirt piles around the property to create a conducive layout for the new surface.
Once the contractor completes excavation, it is time for grading. Most grading services rely on grading equipment that features spade-like metal to scrape along the ground’s surface. As it rolls along, the metal pushes the topsoil to form an even layer. The process also reduces pits and bumps on the surface to create a stable slate for contractors to lay the new foundation.
Guide to the Grading and Excavation Process
Step One: Land Clearing
Before any road construction can begin, the site starts as a parcel of land. This land is also known as the project site. The site can either be an unpaved roadway or an undeveloped space filled with trees and other natural elements.
Once a developer or municipality purchases the land, it must be cleared to begin road construction. This process is also known as land clearing, and includes removing trees, undergrowth, and problematic elements such as large boulders.
Step Two: Site Excavation
Once the site is clear of any growth, excavation can begin. Excavation includes moving the earth or sloping the land with heavy equipment.
For instance, if you were constructing a highway offramp, you need to build up the ground to create enough surface strength for the freeway pillars and concrete roadway. You would also need to excavate the surface and remove the earth to carve out where the road will go. This excavation process will include removing boulders, dirt, and any obstacles that would get in the way of the future structure.
Road construction also includes creating ditches for proper irrigation. Contractors will create these ditches during excavation by removing soil and forming divots in the earth for water to flow. Since water always takes the path of least resistance, creating ditches in the road will give water a slope to redirect water away from the roadway or structure.
Step Three: Grading
Once a site is clear and obstacles excavated, contracts will grade the site to prepare for installing a new surface. Land grading is the process of leveling the site or land for construction. It is a separate process from site excavation because rather than moving the earth, you are shaping it to level it out.
Many factors go into land grading, including the quality and type of the soil, erosion control, density of the site, and more. There are a few basic principles road construction contractors use when grading a surface for concrete or asphalt pavement. Following these principles will help maintain the integrity of the road and avoid unwarranted damage on the roadway’s surface.
Surface Angle
When grading a gravel road, the ideal horizontal angle contractors use for the grading equipment is between 30 and 45 degrees. This surface angle offers the best control over natural material. It also ensures that any loose aggregates won’t slip out from the leading edge of the equipment.
Surface Pitch
Contractors try to find an ideal surface pitch when using heavy-level equipment where the blade edge touches the ground. If the pitch is too far back, the graded material won’t move smoothly enough for materials to get to the other side. If the pitch is too far forward, the blade won’t scrape enough of the road surface to get a level angle.
Operating Speed
Contractors running the equipment must keep the motor grade at a slow and steady pace. Excessive speed can cause loping or bouncing, which will force the blade into inappropriate positions. These irregular movements will then cause depressions and ridges on the road surface.
Crowning
The surface must form a crowing position to ensure proper drainage. But if the crowning slope is too excessive, the roadway won’t be safe enough for driving, causing drivers to drift towards the shoulder of the road. Contractors typically use a recommended cross slope of 1.27 cm crown per 30 cm.
Drains and Sewers
Drainage is a critical element because improper drainage will greatly reduce the new pavement’s life expectancy. Contractors will need to create the foundation of drains and sewers during the excavation and grading process. The center of the road must be higher than the edges so water will run off into the storm sewers. The minimum recommended depth and width for these ditches is 30 cm. However, areas with heavier rainfall or water runoff will require larger ditches.
Shoulder
When grading a new road, contractors must slope the shoulders away from the crowned surface, as well. This formation will also help facilitate drainage, pushing water into ditches. These shoulder areas are usually more sloped than the crown.
Our contractors will then place gravel in 12-inch layers over the surface to complete grading and excavating services. Then, they will moisten and compact each layer until the site reaches the necessary height requirements. Once complete, the site is ready to install concrete or pavement.
Grading and Excavation Contractors
Most land is not immediately ready for construction. It takes a lot of time, effort, and technique to prepare a site. Do it right, and grading and excavating will set the structure of your asphalt parking lot or road up for success. It will also determine the grade at which the water will flow, ensuring proper drainage.
Even if site preparation may seem like a project you can do yourself, leave it to the experts. Without undergoing a professional excavation and grading process, your surface could come out uneven, ultimately causing unnecessary damage.
We offer grading and excavation services throughout the Intermountain West with offices in Utah, Arizona, Nevada, Idaho, New Mexico, Wyoming, and Montana. Some of our grading and excavating services include:
- Sediment controls
- Rough grading
- Fine grading
- Earth excavation
- Mass excavation
- Stabilization
- Importing and exporting fill dirt
- Onsite bio-soil
- Mining and replacing
- Borrow excavation
- Retaining walls
- Land clearing and site demolition
- K-TEC Scrapers
As an experienced Utah excavation company, we can identify potential problems like water tables or soil stability and then take the necessary steps to prepare a site for road installation. Having the skill and knowledge to address each site’s unique characteristics will help prevent future problems with the surface like sagging, separating, or cracking.
Our grading and excavation process is more efficient than ever, so you can finish your surface build on-time and on-budget. Morgan Pavement is the largest private, self-performing asphalt maintenance company in the State of Utah. Our unwavering commitment to quality and service has made us a leader in the asphalt paving and maintenance industry.
From site excavation and grading to installation and maintenance, rely on Morgan Pavement for all your road contracting needs.
