Creating Pathways That Last (Part One of Two)
So You Want or Need a Pathway.
First question: What are your goals?
There are likely multiple. We understand.
At the root level the three most common goals we hear about are:
- Functionality – controlled terrain
- Aesthetically appealing
- Constructed to last
What makes up various pathway types and what are the common issues?
Natural pathways come in all shapes, sizes, and colors. The first thing to consider is the traffic placed upon the pathway. A very crowded botanical garden path or a maintenance vehicle access road will require different support than a lightly used foot trail. A pathway – in engineering terms – must be designed to provide the correct amount of load bearing as well as shear strength to support the traffic placed upon the surface (be sure to consider the frequency of this traffic as well). This load bearing and shear strength requirement can be met naturally using the structure of the aggregate or with chemicals and geosynthetics. Soil particle structure, depth and slope of the pathway surface, natural makeup or man-made construction of the base layer, and strength of the soil’s natural binding can all increase load bearing and shear strength. When these elements are incorrect in a pathway the result can yield:
- Reduced longevity
- Erosion from traffic
- Reduced accessibility for users
What is or what will the pathway be made of? Examples:
- Decomposed granite
- Crushed stone
- Sand (easy now…)
How high is the load bearing and shear strength of the pathway?
This is an incredibly important aspect as it pertains to erosion and how to combat it before it becomes an issue.
Speaking of erosion…
What does weather do to the pathway?
Natural pathways can be appealing. Porosity of natural materials allow water to percolate down into the soil. This can allow the path to manage some storm water and also keeps the surface cooler, reducing the heat island effect. The type of aggregate and slope of the pathway’s surface layer, will affect how the path responds to water. When these elements are incorrect the result will be reduced longevity due to rain creating:
Plan on routine maintenance.
All natural materials will develop loose surface rock particles which is part of the natural look. It reminds users that the path is not concrete or asphalt. Many natural materials can appear to be very stable after the initial installation, but will continually produce greater amounts of loose rock ever more quickly due to weather/aging. If there is too much loose rock, this will create much more maintenance and result in a renovation too quickly. If clay the pathway will be muddy during wet seasons and dusty during dry seasons.
That brings us to what the pathway is constructed of from the aggregate particle structure and soil engineering standpoint.
Materials such as decomposed granite, crushed granite, or other types of crushed stone are considered “soils/aggregates.” These aggregates contain soil particles such as sand, silt, and clay, along with gravel or rock elements. Soil particles are like the DNA of the pathway. They decide how your pathway will perform. Soil structure is the composition and arrangement of particles and pores; the open voids that occur between and within soil particles. If base and slope conditions are constructed properly, then soil structure will determine the load bearing and shear strength, or traffic resistance, of the pathway.
Clay is the only soil particle that has cohesion without water. Clay particles give cohesion for load bearing and shear strength, but when the concentration of clay particles becomes too high, or the moisture content becomes too high it will destabilize and become muddy. Sand and rock particles provide a more sound structure. The amount and size of rock particles, angularity, and hardness will change the load bearing strength of the pathway.
Regardless of the challenges that a pathway will pose, there’s are ways to make the makeup of the path and the environment around it manageable and built to last. Global Environmental Solutions has a couple of products in its environmentally friendly arsenal that will make any job easier – at the outset, or from the maintenance vantage points. Learn more about our DirtGlue® polymer, our DGE Polymer Pavement System, and more. Stay tuned for our second installment of our pathway series which will dwell on evaluating your pathway construction and the substrate that makes it what it is, environmental challenges, and ADA compliance thoughts.
Until then, give us a shout to discuss any of your unique pathway projects and we’ll consult some solid ways to increase the performance, longevity, and quality of the area in question – from the planning phase, through existing pathways that are in need of a managerial “upgrade.” Reach out to GES today! We’re here to answer any and all of your questions and our products are for the earth, with the earth in mind!