What’s on the CBR & Subgrade poster
A definition and 6 facts worth remembering.
CBR compares a soil's resistance to a standard plunger against that of crushed stone, as a percentage.
- An index for design, not a strength parameter
- Tested soaked where the ground can wet up
- Low CBR means a thicker pavement above
- Capping raises a weak formation to workable
- Traffic is counted in standard axle loads
- Damage rises roughly with the fourth power
- Soft clay subgrade — CBR 1 to 3%
- Well graded granular — CBR above 15%
- A car and a loaded lorry share the road, but the lorry does nearly all the damage.
Educational reference. Design CBR and traffic loading are set by the governing pavement design standard.
Questions about the CBR & Subgrade poster
- What’s on the CBR & Subgrade poster?
- A definition and 6 facts worth remembering. CBR compares a soil's resistance to a standard plunger against that of crushed stone, as a percentage. An index for design, not a strength parameter; Tested soaked where the ground can wet up; Low CBR means a thicker pavement above; Capping raises a weak formation to workable; Traffic is counted in standard axle loads; Damage rises roughly with the fourth power; Soft clay subgrade — CBR 1 to 3%; Well graded granular — CBR above 15%; A car and a loaded lorry share the road, but the lorry does nearly all the damage.. Educational reference. Design CBR and traffic loading are set by the governing pavement design standard.
- Who is the CBR & Subgrade poster for?
- CBR & Subgrade belongs to the Civil Engineering section rather than to a school year, because engineering is not something one grade owns. Anyone learning transportation can pin it up — a beginner, a student mid-course, or someone revising years later.
- When should you use the CBR & Subgrade poster?
- Turning a ground investigation result into a pavement thickness. A wall chart earns its place by being glanceable from where the work is happening, so CBR & Subgrade belongs on the wall where that engineering work actually happens, within glancing distance, rather than filed away.
- What other posters go with CBR & Subgrade?
- Road Cross Section, Mass Haul and Horizontal Curves sit alongside CBR & Subgrade in the Civil Engineering section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.Road Cross SectionMass HaulHorizontal Curves
- Is the CBR & Subgrade poster free to download and print?
- Yes. CBR & Subgrade downloads as a free PDF with no account, no email and no watermark, like everything else in the Civil Engineering section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
- What size does the CBR & Subgrade poster print at?
- CBR & Subgrade is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of CBR & Subgrade loses nothing.Printing guide
Related posters
Charts that sit alongside CBR & Subgrade on the same wall.
Browse every Civil Engineering poster, or start from the full catalogue.