A soil-aggregate crushing-energy meter

An improved technique for measuring the energy of crushing of soil aggregates was developed. Criteria for the improved system were: (i) energy must be measured quickly and accurately, (ii) a digital readout should be provided in convenient units, (iii) the system must perform tests both independently and in parallel with a previous method, (iv) the force on the sample at its initial fracture should be recorded, and (v) the system must be portable. The system developed consists mainly of two pnrfs. A small crushing vise was constructed that can be hand-driven or mounted in existing test equipment. A computer module measures the force on the sample and the displacement of the crushing mechanism using a load cell and a displacement transducer. The force times dis-placement product is numerically integrated to find the crushing energy. The entire system fits easily into a hard-shelled camera case (530 by 430 by 190 mm) and is powered from a single 110 V, 60 Hz electrical outlet. The design criteria were met, and measurements taken by the new system agreed well with previous methods having a coefficient of determination (9) of 0.999. Additional Index Words: aggregate stability, soil structure, rupture stress