Sampling is of equal importance to the test and the person collecting the samples must exercise every precaution to obtain samples that will show the true nature and condition of the material they represent.
Taking Composite Samples from Stockpile
- Using a front-end-loader, dig into the stockpile and set aside small piles of 10 to 15 tons of material.
- When building small piles, the loader bucket should be kept as low as possible and roll the material out of the bucket rather than dumping the material. This technique is applied to reduce the separation of aggregates.
- Each additional bucket load of material is obtained and placed evenly over the previous one in the same manner as described above.
- Mix the small lumps well. Using a loader bucket, go to the end of the rectangular pile and roll the material up. Keeping the loader bucket as low as possible, push the bucket into the material until the front of the bucket passes through the midpoint of the original pile. Slowly lift the loader bucket up and roll it forward to make a good mixture of ingredients. Move to the opposite end of the pile and repeat this mixing process until the pile is evenly mixed.
- The heap is now ready for sampling. Do not hit from above. The sample is taken at the center of the volume which is about one third of the height of the pile.
- The shovel is inserted into the material to its full depth horizontally and raised vertically. Continue this process until the required amount of sample is collected.
Fine aggregates are sampled using the same techniques used to sample coarse aggregates, except a sample tube or a fire shovel is used instead of a larger shovel.