Thank you for your post "Concrete school". It helped a lot. I understand, You do not advise to mix the Concrete by myself, however if I have to do it by myself, please advise on the mixing technique. I have to put up a 2' tall Concrete walls to support my deck. My materials are Portland cement, fine yellow sand, river gravel (1.5'' or 2'' in size). What is your recommended mix ratios of the cement, water, sand and the gravel. I will do my very best to be very consistent during mixing. I appreciate your assistance and thank you in advance.