What Is Grasscrete?
Grasscrete is an permeable paving system that allows the grass to grow between steel-reinforced concrete, mimicking natural processes and allowing rainwater to seep into the soil.
Grasscrete is one of the ecological pavements methods where instead of the plain paving surface, vegetation or grass is grown on the surface, which gives an appealing look to pavements or driveways.
Grasscrete consists of a reinforced cellular cast on-site concrete on that one can grow natural grass by filling those voids with either soil or stones. These voids are created with the help of plastic formers (generally called moulds).
It is ideal for low-traffic areas such as car parking, driveways, pathways, etc. This type of pavement is widely adopted in major cities and modern designs because of its aesthetically appealing and environmentally favorable.
Types Of Grasscrete
- Stone Filled Grasscrete
- Partially Concealed Grasscrete
- Concealed Grasscrete
1. Stone Filled Grasscrete
As the name suggests, in stone-filled grasscrete instead of soil, crushed stones are filled between the concrete. These crushed stones’ size comes in a range of 1/2 inches to 3/4 inches.
Generally, the draining capacity of stone-filled grasscrete rates up to 480 inches per hour with 100% water retention. The main reason to consider this one is that it is considered a low-maintenance design, and it is best suited for traffic sustained areas and provides max percolation rates.
- Military Installations
- Access Roads
- Vehicle Parking
- Fire and Emergency Access
2. Concealed Grasscrete
In concealed grasscrete, a layer of soil with a 1-inch thickness is laid on the concrete. While the concrete below has a depth of five and a half inches. The vegetation or the grass laid on the soil surface. These types of grasscrete are best suited for low-traffic areas.
- Low traffic access roads
- Overflow vehicle parking
- Fire and emergency access
3. Partially Concealed Grasscrete
In this type of grasscrete, the vegetation or the grass is placed parallel to the concrete. Usually, concrete with a thickness of 51/2″ is provided along with a half-inch space to protect the root alongside the vegetation.
Partially concealed grasscrete is eco-friendly and pleasing in appearance. It is most suited for sustained traffic areas.
- Road Shoulders
- Access Roads
- Fire and Emergency Access
- Vehicle Parking
Advantages Of Grasscrete
There are various advantages, including Economical, Structural, and Environmental benefits.
Less Operating costs
Stone-filled grasscrete is widely used in patios or driveways, and these are commonly used because of its low maintenance costs. In case of clogging of voids, they can be cleaned easily.
Less Requirement of Expensive Infrastructure
As grasscrete allows natural water to infiltrate grassroots, there is no need for expensive stormwater instruments or infrastructure such as gutters, underground piping, scrubs, etc.
Grasscrete has more life span when compared to conventional types of paving systems. There are some examples where grasscrete was installed in 1974, and it is still in place today.
Grasscrete is manufactured with recycled material right from the manufacturing process of concrete mix to fill sub-layers and voids. It is 100% eco-friendly.
Infiltration of stormwater decreases the runoff and maintains the natural stability of groundwater recharge. As we know, infiltration improves water quality through bio-retention.
Reduces Heat Island Effect and Increases Green Space
Any hotter built-up area than the nearby rural areas is known as the heat island effect; vegetation or any visually appealing green space can reduce this heat island effect, which creates an attractive, comfortable, and claiming atmosphere.
No need for Edge specification
Usually, some modular precast concrete requires edge restrictions or curbs, while grasscrete does not require edge specifications because it adapts or bends according to adjacent edges and finishes.
Resistance to Differential Settlement
Grasscrete is more resistant to differential settlement than the others; as we know, a monolithic slab usually distributes load weight into the wider surface area, thereby resisting the differential settlement.
High load-bearing capacity
Grasscrete structure has a high load-bearing capacity when used with a saturated sub-base. The structure can support a vehicle load up to 51858 kg.
Shallow depth is sufficient for sub base
Grasscrete can be installed with a thinner sub-base compared to other pavements due to their section thickness and continuous reinforcement.
Installation Process Of Grasscrete
The installation process of grasscrete is an on-site cast process, which is simple and easy. We have described this installation process in a step-by-step process below.
1. Area Preparation
The first step involves area preparation where grasscrete is installed. Firstly, the area is cleaned and excavated to a certain depth, and then the subbase is laid. After this formwork setup is done for edges, the subbase is covered with sharp sand blind with a thickness of 10mm to 20mm.
2. Lay Formers
Formers with 60cm x 60cm edge to the edge must be placed in the second step. These are cut wisely to fit the available space. Then the plastic formers of grasscrete are laid alongside each other by leaving a margin of 100mm at edge and joints.
3. Mesh Reinforcements
Now mesh reinforcement is placed over formers. This mesh must be placed on the up spacers, which are located between the former’s main upstand.
4. Pouring Concrete
After placing the mesh, concrete is poured into formers with the help of staging boards. One must ensure that the concrete is placed around formers and mesh properly and leveled to the top of the formers.
A sweeper is used to level the concrete on the top of formers, the margins are toweled, and the concrete is allowed to set for 48 hours.
5. Melt the Form Tops
With the help of an LPG flame gun, the plastic former tops are burnt or melted. It is recommended to provide each former top with a long steel pipe to provide a leading-edge for the flame.
6. Soil and Seed
At last, the empty voids in grasscrete are filled with fine soil and then watered to allow settlement. And then, grass seeds are sowed in the soil then watered daily over two weeks to establish a grass layer.