ROMAN CONCRETE Also called `Opus Caementicium` was used in construction during the Roman period throughout the world. It is a hydraulic cement made of a mixture of slaked lime, pozzolanic material and aggregates. In presence of water the hardening process takes place in three steps:
1. Evaporation of excess water, 2. Carbonation of slaked lime, and 3. Hydration reaction of slaked lime and pozzolana. As a result of the hardening process CaCO3 and hydrated calcium silicate are formed.
The presence of the hydrated calcium silicate give this type of cement its superior strength compared to the normal mortar based on the non-hydraulic lime cement.
This type of cement was reported in many archaeological structures in Jordan, dating back to the Roman period, it was detected in the following archaeological sites: Amman Citadel, Jerash (Gerasa), Umm Qais (Gadara), Pella, Abilla, Madaba, Petra, and Barsinia. DEWATERING MACHINE It was a device widely used for raising water to irrigate fields and dewater mines. Other lifting machines include the endless chain of buckets and the reverse overshot water-wheel.
The Romans used water power, and watermills were common throughout the Empire, especially to the end of the first century AD. They were used for corn milling, sawing timber and crushing ore. The Romans were the first culture to assemble all essential components of the much later steam engine. With the crank and connecting rod system, all elements for constructing a steam engine (invented in 1712) â€” Hero's aeolipile (generating steam power), the cylinder and piston (in metal force pumps), non-return valves (in water pumps), gearing (in water mills and clocks) â€” were known in Roman times.
However, the Hero's aeolipile was a reaction engine, inefficient as a stationary engine. The first useful steam engine did not use steam pressure at all, but followed up a scientific advance in understanding air pressure (Oleson, J. P., 1984, Lewis, M.J.T.,1997, Lucas A., 2006 and Ritti, T. et al, 2007).