since you are going to have to keep the bucket high to avoid spillage, make SURE you have a good counterweight.. I moved a bunch of 'crete with my 33D, and it was fine, but I had to be REALLY careful since I had to rely on the weight of the filled tires, as I couldn't fit where I needed to go with the only cw I had at the time, my LR72 rake.. I still don't have a weight box made..
We shot the 'crete right into the bucket from the truck, it was fine.
Make sure to rinse the bucket before it dries too.