Terms we use
The engineering and trade words on this site, in plain English, from A to Z. If a word you need is missing, ask us: sales@gridmats.com.
- Base
- The compacted layer of crushed stone under the surface. It spreads the load of the wheels to the ground. The GridMats grid sits on the base.
- CBR (California Bearing Ratio)
- A test of how strong the ground is. A higher CBR means firmer ground, which needs a thinner base.
- Cell confinement
- The grid's cells hold the infill in place, so it cannot spread sideways under wheels. This is what lets loose stone or gravel behave like a firm surface.
- Cement-treated gravel (S1)
- Stone chips mixed with a little cement, filled into the grid and compacted. It sets into a hard surface with no saw-cut joints.
- Compaction
- Pressing a layer with a roller or plate compactor so that it becomes dense and strong.
- Cube test
- Small cubes of a cement mix are made on site and crushed in a laboratory after 7 or 28 days to check their strength. An S1 surface opens to trucks once its 7-day cubes reach 2 MPa.
- DLP (defect liability period)
- The period after handover in which GridMats deals with manufacturing defects in the products it supplied: 1 year, on the conditions in our Terms and Conditions.
- Ex-works, ex-GST, ex-freight
- A price at our factory, before GST is added and before transport.
- FOB (free on board)
- An export price that includes delivery onto the ship at the named Indian port.
- GreenPro
- The Confederation of Indian Industry's (CII) certification for green products.
- Gross vehicle weight
- The total weight of a loaded vehicle. We describe trucks this way, for example "up to 49 t gross"; the pavement itself is designed from the axle loads.
- GSB (granular sub-base)
- A layer of graded crushed stone or gravel laid on the prepared ground, below the base.
- Hold point
- A stage of the work where the next step waits until the last one has been checked and released.
- Infill
- What fills the grid's cells: stone chips, gravel, soil and grass, or concrete.
- Installed cost
- The cost of the finished surface per sq ft or m²: the grid, the base, the infill and the labour. It depends on the site, so it is designed for each site.
- IRC (Indian Roads Congress)
- The body that publishes India's road design codes.
- kg CO₂e
- Kilograms of carbon dioxide equivalent: all the greenhouse gases a product causes, counted as if they were carbon dioxide.
- Lab load test (t/m²)
- A panel is pressed in a laboratory until it fails, and the load is given in tonnes per square metre. It compares panels; the capacity of a finished road comes from its design for the traffic and the ground.
- LCA (life-cycle assessment)
- A count of the greenhouse gases a product causes over its life, in kg CO₂e per m².
- m² and sq ft
- Square metres and square feet: 1 m² = 10.764 sq ft. We show prices per sq ft first, with the price per m² in brackets.
- M25 concrete
- Concrete with a strength of 25 MPa at 28 days.
- Modulus improvement factor
- How much stiffer a layer of stone becomes with the grid than without it, measured in a laboratory.
- MPa (megapascal)
- A unit of strength or pressure. 1 MPa is about 10 kg on each square centimetre.
- Permeable
- Lets rainwater soak through the surface into the ground instead of running off.
- PO (purchase order)
- The buyer's order. With GridMats, on-site training is built into the product rate, so there is one PO.
- SOP (standard operating procedure)
- Our step-by-step installation method, which we train your contractor's team to follow.
- Subgrade
- The natural ground under all the layers of a road or yard.
- VDF (vehicle damage factor)
- A number that turns the real mix of vehicles into standard axle loads, so a pavement can be designed for its traffic.
- WMM (wet mix macadam)
- A base layer of graded crushed stone mixed with water, laid and compacted.