Often on a bag of cement the instructions will relate the quantities in terms of bags of cement with wheelbarrows of sand and stone. They claim that 2bags cement = 1 wheelbarrow. I found that my wheelbarrow can only take about one and half bags of cement. Therefore I have been using less sand than I probably should have.
Is it possible that too little sand in a concrete mix makes it weaker, or does it simply just yield less concrete?