What is the maximum allowable loading for #4 openings and greater?

The maximum allowable loading for #4 openings and greater is based on established guidelines for ensuring that the material being tested does not exceed certain limits that could compromise the integrity of the sieve or the accuracy of the results. In this context, the correct choice indicates that the maximum loading should not exceed 2.5 times the sieve opening in kilograms per square meter.

This standard is designed to prevent excessive loading that might clog the sieve, alter the flow of materials, or lead to inaccurate measurements due to the potential for deformation or failure of the testing apparatus. By adhering to this limit, inspectors can ensure that the testing environment remains consistent and that the collected data accurately reflects the material's characteristics.

The other options suggest higher multipliers, which would not be suitable for maintaining the testing integrity. Choosing a multiplier lower than 2.5 would not align with the need for a reasonable balance between load capacity and effective material processing through the sieve openings. Thus, 2.5 times the sieve opening represents an established best practice in the field of soils and aggregate inspection for maintaining accuracy and reliability in testing.