"Numerous discoveries had still to be made about the critical water-cement ratio in the “mix design” and the susceptibility of the material to environmental attack."
"This mix requires a water-cement ratio between 0.45 and 0.5."
"The TARA Vibrator provides a unique mechanism suspended on leather belts, which allows for the vibration to be controlled by adjustable tie rods, depending on the type of cement mix, availability of materials and water-cement ratio."