The load-and-haul cycle is the repeating process used to move soil, gravel, rock, or debris on a construction site. A loader fills a truck, the truck hauls the material, dumps it at a target location, and returns for another load. This cycle matters because small delays repeat many times and can greatly reduce productivity.
Matching loaders to trucks helps crews move more material with less fuel, less waiting, and fewer machine hours.
Key Facts
- Cycle time = load time + haul time + dump time + return time + delay time
- Truck payload = material volume in truck × material density
- Loader passes needed = truck capacity ÷ loader bucket payload
- Productivity = total material moved ÷ total time
- Best matching often uses 3 to 5 loader passes to fill one truck efficiently
- Haul time = haul distance ÷ loaded travel speed, and return time = return distance ÷ empty travel speed
Vocabulary
- Load-and-haul cycle
- A repeating construction process in which material is loaded, transported, dumped, and the truck returns for another load.
- Wheel loader
- A rubber-tired construction machine with a front bucket used to scoop, lift, and load loose material.
- Dump truck
- A truck with a tilting bed used to haul and unload bulk material such as soil, gravel, or rock.
- Payload
- The weight or volume of material a machine carries during one trip.
- Cycle time
- The total time required to complete one full load, haul, dump, and return sequence.
Common Mistakes to Avoid
- Ignoring return time makes productivity look too high because the truck must still travel back empty before the next load can begin.
- Matching only by bucket volume is wrong because loose material density and bucket fill factor affect the actual payload.
- Using too small a truck for a large loader causes frequent truck changes and waiting, which wastes loader capacity.
- Using too large a truck for a small loader causes long loading times because many bucket passes are needed to fill one truck.
Practice Questions
- 1 A wheel loader carries 3.0 cubic meters per bucket pass, and a dump truck holds 12.0 cubic meters. How many passes are needed to fill the truck?
- 2 A truck spends 4 minutes being loaded, 6 minutes hauling, 2 minutes dumping, 5 minutes returning, and 1 minute waiting. What is the total cycle time, and how many cycles can it complete in 1 hour?
- 3 A site has one loader and several trucks. Explain why adding more trucks may not increase total production if the loader is already working nonstop.