What is the granular sub base?
The granular subbase forms the lowest (bottom) layer of the pavement structure, and acts as the principal foundation for the subsequent road profile, provides drainage for the pavement structure, and protects the structure from frost.
What is GSB material?
GSB material is a mix of sand & gravels, crushed stone & broken rock. GSB material typically contain crushed stone > 50%. Material having CBR > 30% & PI < 6%. Water absorption < 2% & Agg impact value (AIV) < 40%. Material should be free from clay & organic matters.
What is Type 2 Sub Base?
Our Type 2 is a crushed aggregate with extra dusts and fines, which makes the perfect sub base for a range of domestic and commercial construction projects. Graded to 50mm down to dust and fines no specified grading, it is finer than our MOT Type 1 sub base, as it is composed of fewer larger angular scalpings.
What is the density of GSB?
2.1 g/cc
Granular Sub Base (GSB) Road Material, Packaging Size: 50 kg
| Usage/Application | For Construction |
|---|---|
| Packaging Size | 50 Kg |
| Density | 2.1 g/cc |
What is a Type 3 sub-base?
Type 3 sub-base is a pure crushed granite, limestone or clean crushed concrete. Usually a 40mm product that has been screened to create a reduced fines aggregate. This product is fully certified according to the Specification for Highway Works. This is the most widely used sub-base where less fines are required.
What’s the difference between Type 1 and Type 2 sub-base?
It usually contains finer material than type 1, being composed of fewer angular aggregate sizes also know as scalpings. Type 2 mot can be used for driveways, backfill material, paths and patio areas and to fill in pot holes and compacts down to a hard base.
How is GSB weight calculated?
You multiply the density of the sand by the volume to determine the mass. If you work in SI units, the density will have units of , and the volume will have units of and so when you multiply you are left with the mass in . Then one tonne is equal to 1000 kg.
What is the difference between subbase and base?
Base may consist of unbound materials, such as gravel or crushed stone, or stabilized materials, such as asphalt-, cement- or lime-treated materials. The subbase course is typically a granular borrow that is placed between the base and subgrade. It can be constructed as either a treated or untreated layer.
What is maximum dry density of GSB?
The maximum dry density of Granular Sub Base used in Road Construction must be 2100 Kg/Cum. The maximum dry density of Wet Mix Macadam used in Road Construction must be 2230 Kg/Cum.
What is the permeability of granular sub-base?
Permeability requirements of Granular Sub-base (GSB) is 300m/day as per IRC 37:2012 Flexible Pavement Strength wise GSB is more superior as compared to the subgrade. Brick metal, kankar and crushed concrete is permitted in lower sub-base. Granular Sub-base (GSB) materials shall be free from organic or other deleterious constituents
What are the materials required for granite sub base?
Material Requirement for Granular Sub-base (GSB) 1 River/Natural sand 2 Crushed Gravel 3 Crushed Stone 4 Blast Furnace slag metal 5 Brick metal, kankar and crushed concrete is permitted in lower sub-base.
What is the maximum compact thickness of GSB material?
The material shall be mechanically (viz grader, etc.) spread in uniform layers such that compacted thickness not exceeding 200mm – 250mm with due consideration to loose thickness (compaction factor) of GSB.
What is GSB layer in civil engineering?
Granular Sub-base (GSB) consists of laying and compacting well graded material on prepared sub-grade in accordance with the specifications.: GSB layer is intermediate layer in between Sub-grade and Wet mix macadam. GSB layer is laid in roads and higway works due to its properties .