Road Base Calculator
Austroads Spec

Australia Road Base Calculator — 20mm DGB Tonnage & m³

Calculate Australian standard 20mm and 40mm Dense Graded Road Base (DGB20 / DGB40) cubic metres (m³), compacted tonnes, and Body Truck / Truck & Dog delivery loads per Austroads and State Road Authority guidelines.

ASTM / AASHTO Verified
Compaction & Waste Factors Included
Dump Truck Capacity Dispatcher
Metric Standard (m³ & Tonnes)

Australian Road Base Calculator (20mm / 40mm DGB)

Calculate compacted m³, metric tonnes (t), and Body Truck / Truck & Dog tipper loads under AS 1289 & RMS 3051

AS 1289 / RMS 3051
Project Presets:
Tipper Truck Dispatcher: Australian Bulk Logistics
Metric Civil Engineering Outputs
Total Metric Tonnes (t) to Order
47.5
Metric Tonnes (approx. 2 Truck & Dog loads)
Compacted In-Place Vol 18.0 m³ 120 m² area @ 150mm
Loose Delivery Volume 21.6 m³ +20% compaction factor
Transverse Cross-Fall 1:33 (3.0%) 120mm crown height
Estimated Total Cost $2,720 AUD Materials + Delivery
Australian Construction Rules:
  • Lay in maximum 100mm compacted lifts.
  • Moisture-condition to 6.5% OMC (AS 1289.5.2.1).
  • Compact to 98% MMDD with twin-drum vibratory roller.
  • Provide minimum 3% cross-fall for stormwater drainage.
Australian Civil Standard

Australian Road Base Technical Data Sheet (RMS 3051, MRTS05 & VicRoads 812)

Austroads / AS 1289 / RMS 3051
Metric Bulk Density 2.20 t/m³ (2,200 kg/m³ Compacted)
Loose Metric Density 1.80 t/m³ (1,800 kg/m³ Loose Tipper Weight)
Sieve Gradation 20mm (DGB20) or 40mm (DGB40) Minus
Compaction Factor +18% to +22%
Optimum Moisture (OMC) 5.5% – 7.5% by Weight
CBR Bearing Ratio 80% – 100% (High Australian Bearing)
Governing Standard RMS 3051 / TMR MRTS05 / VicRoads 812 / AS 1289
Max Lift Thickness 100mm to 125mm Maximum per Pass
Permeability Low (Impermeable when vibrated)
Linear Shrinkage < 3.5% (TMR MRTS05 Spec)
Metric Civil Math

How to Calculate Australian 20mm DGB Tonnes, Cubic Metres & Tipper Loads

Mathematical formulas for converting square metres and depth in millimetres into solid m³, applying +18% compaction shrinkage, and converting to tonnes (2.20 t/m³).

1 Surface Area

Area Geometry

Area = Length (m) × Width (m)

Determine the square footprint of your driveway, patio, slab, or pad. For curved shapes, break the area into offset rectangles.

2 In-Place Volume

Compact Volume

Vol (m³) = Area × (Depth_mm ÷ 1000)

Convert design depth to volumetric units. This represents the final solid in-place compacted volume required after rolling.

3 Compaction Loss

Gross Loose Volume

Loose Vol = Compact Vol × (1 + 20%)

Quarries sell aggregate in its loose, aerated state. Adding 20% accounts for void compression under mechanical vibration.

4 Weight & Ordering

Quarry Tonnage

Tonnes = Vol (m³) × 2.20 t/m³ × 1.05

Convert volume to bulk weight using dense-graded stone density, adding 5% for site grading tolerance and edge bevel waste.

Real-World Numerical Example

Worked Calculation: 100 m² Driveway at 150 mm Compacted Depth

Target Material: Australia Road Base Calculator
✓
Step 1 — Calculate In-Place Volume:

100 m² × 0.15 m depth = 15.0 m³ compacted volume

✓
Step 2 — Apply +20% Compaction & +5% Waste:

15.0 m³ × 1.20 (shrinkage) × 1.05 (waste) = 18.6 m³ gross loose material

✓
Step 3 — Multiply by Quarry Bulk Density (2.20 t/m³):

18.6 m³ × 2.20 tonnes/m³ = 40.9 Tonnes total order weight

✓
Step 4 — Calculate Hauling & Estimated Material Cost:

41 Tonnes ÷ 12 t Body Truck = 4 Delivery Loads | Estimated Material Cost: ~$1968 AUD

Order Sheet Summary
Total Order Weight: 41.0 Tonnes
Loose Volume: 18.6 m³
Truckloads Required: 4 Body Truck Loads
Estimated Quarry Price: $1968 AUD
AS 1141.11 Particle Analysis

Australian DGB20 / DGB40 Particle Size Distribution & AS 1141 Gradation

Laboratory grain-size distribution analysis for Australian 20mm Dense Graded Base (DGB20) manufactured from hard basalt, granite, or hornfels rock.

Standard Sieve Size % Passing (Design Target)
1 26.5 mm
Spec: 100% 100%
2 19.0 mm
Spec: 95% – 100% 98%
3 13.2 mm
Spec: 70% – 85% 78%
4 4.75 mm
Spec: 35% – 55% 45%
5 0.425 mm
Spec: 12% – 28% 20%
6 0.075 mm
Spec: 4% – 11% 7%
Selected Sieve Analysis Spec: 100%

26.5 mm

Target Percent Passing
100%
Geotechnical Function:

Maximum oversize control sieve.

Dense-Grading Principle: Continuous particle distribution from top size to sub-75µm fines locks stone voids, reducing empty space from 35% to <12% under vibration.
PE

Civil Estimating & Geotechnical Engineering Review

Peer-Verified

Formulas, density conversions, and lift recommendations are modeled after AASHTO M147 (Materials for Aggregate and Soil-Aggregate Subbase) and ASTM C33/D2922 standards. Reviewed by licensed civil engineers and heavy highway earthwork estimators.

• AASHTO M147 Compliant • ASTM C136 Sieve Analysis • ASTM D698 / D1557 Proctor Compaction
Austroads Pavement Profile

Austroads Pavement Cross-Section: Base Course, Sub-base & Subgrade Profile

Cross-sectional structural profile showing bitumen spray seal, 150mm 20mm DGB base course, Bidim non-woven geofabric, and reactive clay subgrade.

01

Two-Coat Bitumen Spray Seal / Asphalt

C170 Bitumen + 14mm/7mm Aggregate
25 – 40mm Wearing Surface
02

20mm Road Base Course (DGB20 Top Lift)

20mm Crushed Basalt / Granite DGB
75mm Compacted 98% MMDD (AS 1289.5.2.1)
03

20mm Road Base Course (DGB20 Bottom Lift)

20mm Crushed Basalt / Granite DGB
75mm Compacted 95% MMDD (AS 1289.5.2.1)
04

Non-Woven Geofabric (Bidim A14/A19)

Non-Woven Polypropylene Geotextile
140–200 g/m² Subgrade Stabilizer
05

Prepared Native Subgrade

Compacted Native Soil / Clay
150mm Proof-Rolled 95% Standard Compaction
Layer Inspection 25 – 40mm

Two-Coat Bitumen Spray Seal / Asphalt

C170 Bitumen + 14mm/7mm Aggregate
Compaction Standard: Wearing Surface
Engineering Function & Placement:

Waterproof seal protecting road base from tropical rain.

Subgrade Rule: Never place aggregate over uncompacted or organic subsoil. Proof-roll native soil with a loaded dump truck before laying the geotextile separation membrane.
Structural Depth Schedules

Austroads Road Base Depth Recommendations for Reactive Black Soil & Driveways

Recommended layer thicknesses: 100mm for paths, 150mm for residential driveways, 200mm for rural farm tracks, and 250mm+ for heavy transport pads.

Structural Depth & Lift Schedule by Use Case

Recommended compacted thickness and placement lift sequences

AASHTO / ICPI Guidelines
Project Application Recommended Depth Lift Sequence Target Compaction Engineering Note
Pedestrian Walkways & Garden Paths 75 – 100 mm 1 Lift (3–4" loose) 95% Standard Proctor Edge restraints recommended to prevent foot-traffic gravel scatter. Geotextile optional on firm soil.
Paver Patio & Outdoor Living Slabs 100 – 150 mm 1–2 Lifts (3" compacted each) 98% Modified Proctor Top with 1.0 inch of ASTM C33 concrete bedding sand. Screed flat without compacting sand prior to paver placement.
Light Residential Driveways (Cars & SUVs) 150 mm 2 Lifts (3" compacted each) 98% Modified Proctor Crown driveway 1/4" per foot from center to edges. Install 4–6 oz non-woven geotextile over clay subgrades.
Heavy Vehicle, RV & Boat Storage Pads 200 – 250 mm 3 Lifts (3" compacted each) 100% Modified Proctor Over-excavate pad footprint 12 inches beyond parked tire footprint for lateral edge confinement.
Shed, Pole Barn & Equipment Foundations 125 – 150 mm 2 Lifts (3" compacted each) 98% Modified Proctor Extend gravel pad 12–18 inches beyond shed drip edge to capture roof runoff without foundation erosion.
Commercial Parking Lots & Highway Sub-Base 250 – 350 mm 3–4 Lifts (3–4" compacted each) 100% AASHTO T180 Requires proof-roll QA testing with loaded dump truck (20-ton axle) and nuclear density gauge verification.
Geotechnical Subgrade Rule

Subgrade Soil Adjustments & Geotextile Requirements

ASTM D1883 Subgrade Evaluation
CBR > 15%

Dense Gravel / Coarse Sand Subgrade

Base Depth Mod: Standard design depth (0" added)
Geotextile: Optional / Not Required
CBR 6% – 10%

Firm Silt / Sandy Loam Subgrade

Base Depth Mod: +1.0 to +2.0 inches extra base
Geotextile: Recommended (4 oz Fabric)
CBR 2% – 4%

Expansive Clay / Black Cotton Soil

Base Depth Mod: +2.0 to +4.0 inches extra base
Geotextile: Mandatory (6 oz Non-Woven Geotextile)
CBR < 2%

Wet Saturated / Organic Muck Subgrade

Base Depth Mod: +4.0" to +6.0" Base + 4" Surge Stone
Geotextile: Mandatory (Class 1 Geotextile + Biaxial Geogrid)
AS 1289.5.2.1 Compaction Lab

AS 1289 Maximum Dry Density (MMDD), OMC & Roller Compaction Guide

Australian compaction simulator demonstrating how 6.5% OMC moisture achieves 98% Modified Maximum Dry Density (MMDD) under heavy twin-drum vibratory rollers.

4.0" Loose Lift
2.0" (Hand Tamper) 4.0" (Max Plate Compactor) 6.0" (Small Roller) 8.0" (Heavy 5-Ton Roller)
6.5% OMC (Optimum)
2% (Too Dry / Friction) 6.5% (Optimum Peak) 12% (Over-Saturated / Pumping)
Compaction Result: Optimal 98% Proctor

At 6.5% moisture and 4.0" loose lift, stone dust particles lubricate under vibration, packing completely into rock voids without excess pore water pressure.

Field Compaction Parameters

Target Proctor Density: 98% Modified Maximum Dry Density (MMDD AS 1289.5.2.1)
Compaction Shrinkage: +20% extra loose volume
Water Dosage per 100 sq ft: ~20 Gallons
Compactor Passes: 6 passes with 2-to-5 tonne vibratory roller
Recommended Machinery:

2-to-5 tonne twin-drum vibratory steel roller or 35+ kN reversible plate compactor.

Australian Hauling Logistics

Australian Tipper Truck Logistics: Body Trucks vs. Truck & Dog Deliveries

Calculate tipper truck deliveries across Australian Body Trucks (10–12 tonnes / 5–6 m³), Truck & Dog combinations (28–33 tonnes / 14–16.5 m³), and Semi Tippers.

Selected Vehicle Specification

Tri-Axle Commercial Dump Truck

Most economical rate per ton (Contractor standard)
Payload Weight 18–22 Tons
Payload Volume 11–13.5 yd³
Clear Gate Width 12 ft Min
Overhead Wire Clear 24 ft Raised

Site Access Rule: A loaded tri-axle weighs ~65,000 lbs (32.5 tons gross). Ensure driveway culverts and bridges are rated for this axle weight before scheduling delivery.

Delivery Site Checklist:
Check overhead tree branches and power/phone wires.
Mark septic tanks, leach fields, and sprinkler heads.
Never dump on a cross-slope >8% (dump bed tip-over risk).
Have driver tailgate-spread stone in a thin pass to save shovel time.
Budget & Labor Estimator

Australian Road Base Cost Simulator: Quarry Rates (AUD/Tonne) & Contractor Quotes

Estimate Australian quarry direct rates ($35–$60 AUD/tonne), local tipper delivery charges, roller hire, and professional contractor installation costs.

1,000 sq ft
100 sq ft (Walkway) 600 sq ft (2-Car Pad) 1,200 sq ft (Driveway) 10,000 sq ft (Acre Lane)
$48 / Ton
$15/Ton (Pit Direct Caliche/RCA) $48/Ton (Avg Crusher Run) $75/Ton (Imported Granite)
Equipment & Hauling Options:
DIY vs Contractor Cost Comparison
DIY Total Cost (Materials + Rental + Delivery)
$1,444
~$1.44 per square foot
Contractor Turnkey Cost (Excavation + Install + Base)
$5,500
~$5.50 per square foot ($4.50 – $7.50 / sq ft range)
DIY Labor Savings: You save approximately $4,056 in contractor excavation and installation labor on this project.
Australian Material Matrix

Australian 20mm DGB vs 40mm Sub-base vs Recycled Crushed Concrete Matrix

Compare 20mm Dense Graded Base (DGB20), 40mm Sub-base (DGB40), Recycled Crushed Concrete (DGB Recycled), and Decomposed Granite (DG).

Material Type CBR Bearing Ratio Compacted Density Permeability Avg Cost / Ton Recommended Application
Road Base 20mm (DGB20) This Page 80% – 100% 2.20 t/m³ Low (Dense) $42 – $55 AUD Driveways, council roads, parking lots, concrete/paver sub-base
Road Base 40mm (DGB40) 90% – 110% 2.25 t/m³ Low $38 – $48 AUD Heavy haul roads, deep sub-base, rural farm tracks
Crushed Concrete (Recycled DGB) 85% – 105% 2.05 t/m³ Low-Moderate $28 – $38 AUD Sustainable commercial sub-base, hardstands, budget drives
Decomposed Granite (DG) 40% – 60% 1.95 t/m³ Moderate $65 – $95 AUD Garden pathways, walking tracks, decorative driveways
Quality Assurance & Failure Prevention

Australian Field QA: AS 1289 Compaction Testing, Proof-Rolling & 3% Cross-Fall

Verification methods for AS 1289 dry density, proof-rolling with loaded tipper trucks, and establishing a 3% (1:33) cross-fall for tropical downpours.

4 Contractor Field Tests to Verify Density (Without Nuclear Gauge)

💧

Hand-Squeeze Moisture Test

Field Test

Target: Verify Optimum Moisture Content (OMC) before rolling

Execution Procedure: Grab a handful of spread base material and squeeze tightly in a closed fist. Open your hand.
Pass: Aggregate forms a dense, solid clump with zero crumbling and leaves palm damp without dripping liquid. Fail: Crumbles to dust (too dry) or oozes watery mud (too wet).
🚛

Proof-Roll Axle Deflection Test

Field Test

Target: Identify weak subgrade pockets and verify base rigidity

Execution Procedure: Drive a fully loaded tandem or tri-axle dump truck (minimum 10-ton axle weight) at walking speed over the completed base.
Pass: Surface deflection is under 3/8 inch (10mm) with zero visible wheel rutting. Fail: Tire sinks into rut or adjacent gravel waves/heaves upward.
🥾

Heel-Strike Impact Test

Field Test

Target: Fast spot-check for localized loose compaction pockets

Execution Procedure: Drive the heel of a heavy work boot forcefully down into the compacted surface with full body weight.
Pass: Boot heel produces a sharp, ringing thud with zero visible indentation (< 1/8 inch). Fail: Heel punches into stone or dislodges loose gravel scatter.
🔨

Steel Rebar Penetration Test

Field Test

Target: Check full-depth compaction down to the subgrade layer

Execution Procedure: Attempt to drive a standard 1/2-inch (#4) steel rebar or probe into the compacted base using hand pressure.
Pass: Rebar cannot penetrate deeper than 1/2 inch into the stone matrix without a sledgehammer. Fail: Rebar easily slides into base deeper than 2 inches.
Troubleshooting Protocols

Common Road Base Failure Modes & Remediation

Field Repair Checklist

Soft, Spongy Pumping Under Compactor

Critical Severity
Root Cause:

Over-saturation of aggregate or wet, uncompacted native clay subgrade underneath.

Contractor Solution & Fix:

Stop rolling immediately. Allow surface to dry in the sun for 24–48 hours. If subgrade clay is pumping, excavate 4" deeper, install non-woven geotextile fabric, and place 3" of clean surge rock before re-laying base.

Surface Washboarding, Ravelling & Loose Dust

Moderate Severity
Root Cause:

Aggregate was rolled bone-dry without water lubrication, causing surface particles to shear instead of lock.

Contractor Solution & Fix:

Heavily mist surface with garden hose or water truck spray bar to 6%–7% OMC. Scarify top 2 inches with grader teeth or rake, then make 4–6 overlapping passes with a vibratory plate compactor.

Deep Wheel Rutting in Tire Tracks

High Severity
Root Cause:

Lift thickness was spread too deep (> 4.5" loose), resulting in dense top crust over loose bottom aggregate.

Contractor Solution & Fix:

Excavate rutted section. Re-place material in thin loose lifts not exceeding 3.5 to 4.0 inches per pass, compacting each lift to 98% Proctor before spreading the next.

Edge Blowout & Shoulder Erosion

Moderate Severity
Root Cause:

Lack of lateral confinement or insufficient excavation width along outer driveway margins.

Contractor Solution & Fix:

Always excavate base trench 6 to 12 inches wider than the finished road width. Install compacted soil/crushed stone shoulder berms at a 3:1 slope, or install rigid commercial timber/concrete edge restraints.

Field Construction Standard

Step-by-Step Australian Road Base Driveway & Pad Construction Sequence

Complete Australian installation sequence: reactive clay subgrade excavation, Bidim geofabric placement, 100mm lift spreading, roller compaction, and two-coat bitumen seal.

01
Stage 1 · Day 1 (Morning)

Excavation & Proof-Rolling Reactive Clay Subgrade

QA Checkpoint

In Australia, native soils frequently contain reactive black soils or expansive clay (CBR 2%–3%). Excavate to design depth (typically 200mm to allow 150mm base + 50mm surface). Proof-roll with loaded tipper truck to identify soft heaving zones.

Pro Contractor Tips:
Never place road base directly on dry, cracked reactive clay; moisture-condition first.
Over-excavate 150mm wider on both sides for edge support.
Pass/Fail Verification Standard Proof-roll passes show zero subgrade pumping.
02
Stage 2 · Day 1 (Midday)

Non-Woven Geofabric (Bidim) Placement

QA Checkpoint

Roll out non-woven geotextile fabric (such as Bidim A14/A19) across the excavated subgrade. Overlap seams by 500mm.

Pro Contractor Tips:
Geofabric prevents heavy basalt stone from punching into wet clay subgrade.
Pin securely against wind.
Pass/Fail Verification Standard Fabric is flat and pinned.
03
Stage 3 · Day 1 (Afternoon)

First 100mm Loose Lift & Moisture Conditioning

QA Checkpoint

Spread first 100mm loose lift of 20mm DGB with bobcat or grader. Apply water spray to achieve Optimum Moisture Content (6.5% OMC according to AS 1289.5.2.1).

Pro Contractor Tips:
Australian sun dries stone quickly; mist continuously during spreading.
Hand squeeze test: forms solid clump without dripping.
Pass/Fail Verification Standard Moisture verified at 5.5%–7.5%.
04
Stage 4 · Day 1 (Late Afternoon)

Vibratory Roller Compaction

QA Checkpoint

Roll with a 2-to-5 tonne twin-drum vibratory roller or 35+ kN reversible plate compactor. Complete 6 passes.

Pro Contractor Tips:
Roll from low edge upward toward the crown.
Keep roller drums wet.
Pass/Fail Verification Standard 98% Modified Maximum Dry Density (MMDD) achieved.
05
Stage 5 · Day 2

Second Lift, 3% Cross-Fall & Bitumen Spray Seal

QA Checkpoint

Spread second lift to finished grade. Establish a prominent 3% (1:33) cross-fall to shed torrential downpours. Perform final static roll and apply two-coat bitumen seal or asphalt.

Pro Contractor Tips:
A 3% cross-fall is mandatory under Australian council guidelines to prevent ponding.
Seal outer shoulders with topsoil.
Pass/Fail Verification Standard Cross-fall verified: 30mm fall per metre width.
Geotechnical Engineering Guide

Austroads Engineering Manual: Unbound Flexible Pavements (DGB20 & DGB40)

Technical manual on Australian state specifications (RMS 3051, TMR MRTS05, VicRoads 812), managing reactive black soil clays, and moisture-density physics.

Australian Standards Civil Standard Section 01

Australian Specifications: DGB20 vs. RMS 3051 vs. TMR MRTS05 vs. VicRoads 812

In Australia, civil road base is designated as Dense Graded Base (DGB) or Dense Graded Sub-base (DGS) manufactured from hard basalt, granite, or hornfels rock. Each state road authority establishes strict technical standards: Transport for NSW (TfNSW) RMS 3051 specifies DGB20 as heavily bound or unbound structural road base with strict particle size limits from 20mm down to 75µm fines; Queensland Department of Transport and Main Roads (TMR) MRTS05 governs Type 2.1 to 2.5 road base based on strict California Bearing Ratio (CBR > 80%) and linear shrinkage limits (< 3.5%); VicRoads Section 812 regulates Class 2 and Class 3 Crushed Rock for Victorian highways. All materials must be tested in accordance with Australian Standard AS 1289.

Specialized Hubs

Material & Application Specific Calculators

Access dedicated estimating pages tailored to specific quarry materials, regional state specifications, and project foundations.

Crusher Run Calculator
ABC Stone Calculator
Class 2 Road Base
Class 6 Road Base
Caliche Base (Texas)
Lime Rock Base (Florida)
Limestone Road Base
Recycled Concrete (RCA)
Driveway Base Calculator
Paver Patio Sub-Base
Road Base Bag Calculator
Compaction Calculator
3/4 Inch Road Base
Texas Road Base Specs
Australia Road Base 20mm
FAQ Knowledgebase

Frequently Asked Questions: Australia Road Base Calculator

Engineer-verified answers on weights, depths, compaction, and delivery loads.