Shotcrete Rebound Loss Calculator

Calculator Inputs

Project Name (optional)

Helps label exports.

Area (optional)

m²

Use with thickness to compute design volume.

Thickness (optional)

Leave blank if entering design volume directly.

Design Volume (placed)

If area and thickness are given, the calculator uses the larger computed value.

Rebound Loss (%)

Enter a rebound percentage.

Typical ranges vary by method, surface, and nozzle technique.

Other Waste (%)

Overspray, trimming, cleanup, and handling losses.

Unit Cost (optional)

per m³

Used for supply and waste cost estimates.

Currency (optional)

Three-letter code, e.g., USD, EUR, PKR.

Density (optional)

kg/m³

Adds supply and waste mass outputs.

Notes (optional)

Stored in the exported report.

Clear

Formula Used

This calculator treats rebound and other losses as percentages of supplied shotcrete volume.

Design volume (placed): V_d = Area × Thickness
Total loss fraction: L = (Rebound% + Other%) / 100
Supply needed: V_s = V_d / (1 − L)
Rebound volume: V_r = V_s × Rebound% / 100
Other loss volume: V_o = V_s × Other% / 100
Total waste: V_w = V_r + V_o
Waste cost (optional): C_w = V_w × UnitCost

How to Use This Calculator

Enter the design volume you must place, or provide area and thickness.
Set a realistic rebound loss percentage for your method and geometry.
Add other waste to cover trimming, overspray, and cleanup.
Optional: enter unit cost and density for cost and mass outputs.
Press Calculate to see supply, rebound, waste, and cost results.
Use Download CSV/PDF to share results with your team.

Example Data Table

Design Volume (m³)	Rebound (%)	Other Waste (%)	Supply Needed (m³)	Total Waste (m³)
10.000	15	3	12.195	2.195
25.000	20	5	33.333	8.333
8.500	12	2	9.659	1.159

Examples assume losses apply to supplied volume; rounding shown.

Notes for Estimators

Rebound can increase on rough substrates, overhead work, or poor nozzle distance.
Separate “other waste” helps capture trimming and jobsite handling variability.
If you track actual placed versus delivered volumes, update percentages for future bids.

Rebound loss and its estimating impact

Rebound is material that bounces off the substrate during placement. It reduces placed yield and increases cleanup. Estimators treat rebound as a percentage of delivered volume. Common allowances range from 10% to 30% depending on conditions. Small percentage changes can shift total supply noticeably on large tunnel, slope, and lining work. This calculator converts design volume to realistic supply and waste volumes for planning with confidence.

Typical drivers that increase rebound

Rebound rises with overhead spraying, low impact angle, excessive nozzle distance, and poor encapsulation. Coarser aggregate gradation can increase bounce on hard surfaces. Dry processes often show higher variability than wet methods. High accelerator dosage and low moisture can reduce cohesion, raising rebound. Surface roughness, initial setting, and reinforcement congestion also affect adhesion. Track rebound by location and orientation to refine future assumptions.

Separating rebound from other jobsite waste

Projects rarely lose volume only to rebound. Trimming, overspray, pump priming, hose residue, and batch washout create additional losses. Combining all losses into one number hides root causes. This calculator splits rebound and “other waste” so crews can target improvements. Logging waste by bin count or truck tickets supports stronger quantity audits. Use production logs to update each percentage independently and avoid overbuying.

Using density and unit cost for controls

Adding density converts volume waste into mass for disposal, lifting, and haul planning. Unit cost turns waste volume into financial exposure, supporting value-engineering discussions. Effective cost per placed cubic meter highlights the true bid rate when losses exist. Budget scenarios can add disposal fees per ton to reflect landfill or haul charges. When comparing mixes or methods, keep design volume constant and adjust only loss percentages to see impacts.

Field verification and reporting workflow

Start with measured design quantities from drawings or survey. Record delivered volumes from batch tickets and compare to placed volumes from thickness checks. Calculate observed loss percentages and update your standard library by project type. Weekly reconciliation meetings should align tickets, crew notes, and test panel outcomes. Export CSV for estimating files and PDF for daily reports. Consistent tracking improves bid accuracy and reduces material waste over time.

FAQs

1) What does “rebound loss” represent?

It is shotcrete that bounces off and is not incorporated. It is modeled as a percent of supplied volume.

2) Why does the calculator divide by (1 − total loss)?

Losses are applied to the supplied volume. Dividing ensures the remaining volume equals the required design placement.

3) Should I enter design volume or area and thickness?

Either works. If you provide both, the calculator uses the larger computed design volume to reduce underestimation risk.

4) What should I include in “other waste”?

Include overspray, trimming, pump priming, hose residue, washout, and handling losses not counted as rebound.

5) How do I validate my rebound percentage on site?

Compare delivered volumes from tickets with verified placed quantities. Back-calculate observed losses by location and orientation.

6) How can I reduce rebound and waste?

Improve nozzle distance and angle, stabilize air and water, prepare substrate, manage reinforcement congestion, and train nozzle operators consistently.