Q: In the February issue of CONCRETE CONSTRUCTION you have on page 64 in the Problem Clinic section a question and answer entitled Cement and Aluminum. In this you state that very small percentages of aluminum will cause expansion of concrete and quote the use of aluminum powder at the rate of 0.005 percent by weight of cement. Here we use 50 kilogram bags of cement (110 pounds) so at the rate quoted the dose per bag to form an expansive grout is: 110 x 0.005 x 16 ounces per bag. Is this correct or has a slight error been made in the position of a decimal point?