This is what one sack of Quikrete® looks like when it's mixed. You can see a couple of sacks on the ground in the distance. The sacks weigh 27 kg (60 lb) dry. The way we mixed it was for Lisa to slit one sack open, after which I would tip it out into the wheelbarrow while she wielded the garden hose with the sprayer set to a fine mist to keep the dust down. (We both wore dust masks and glasses; concrete dust is very bad for you.) I would then use a concrete hoe to form the dry mix into a mound with a hole in the center (like a volcano) into which Lisa would pour about a liter of water. I would then start mixing the water into the dry mix. Lisa used the sprayer to both keep the dust from flying about and also to add water.
With the concrete hoe, I pushed the mixture around. Lisa continued to add water until the mix reached what seemed to be the the right consistency. I would then roll the wheelbarrow to the work site and Lisa would scoop it into the places we were paving. We kept a watering can (also visible in the photo above) near the work site to add water if necessary.
After using one barrow load, we washed out the wheelbarrow and all of the tools before doing the next one. This keeps concrete from building up on the wheelbarrow and also we could use the wash-out to coat our driveway, the asphalt of which is breaking up and which we cannot afford at this time to have repaved.
From experience, I know that the wheelbarrow will actually hold two sacks' worth of concrete; however, it gets really heavy and difficult to manage. Therefore, we stuck to one sack at a time. It's not moving the wheelbarrow around or even the mixing that gets to me so much as it is lifting those 27 kg sacks of dry mix.
For various reasons, we ended up with six extra sacks of concrete, which will live in the garage until we take on a future paving project. Not soon, though. My arms and back hurt.