Which type of diagram helps determine waste and borrow volumes in highway design?

The mass diagram is essential in highway design for determining waste and borrow volumes because it graphically represents the balance of earth materials required for the construction of a roadway. This diagram illustrates the cumulative quantities of earth that need to be excavated (waste) and the quantities that will be used (borrow) to achieve a balanced cross-section of the roadbed.

By plotting the quantities of material along a horizontal alignment, engineers can visually assess where excess material exists and where additional material is needed. This helps in calculating the volumes efficiently and makes it easier to optimize material usage, saving costs and time during highway construction projects. The mass diagram effectively aids in planning the necessary moves of earth materials during the construction phase, ensuring that the design is both functional and economical.

In contrast, other types of diagrams serve different purposes. A topographic diagram illustrates the terrain's surface features, while a contour diagram represents lines of equal elevation and helps visualize the shape of the land. An elevation diagram displays vertical profiles, which can inform about changes in height but does not provide the specific volumetric analysis that a mass diagram does.