In many countries contractors buy ready mixed concrete from RMC companies. Ready-mix concrete is the one which is manufactured in a factory or batching plant, according to a set recipe and then delivered to a work site by truck mounted in–transit mixers. This results in an accurate mixture that allows specialty concrete mixtures to be developed and implemented on construction sites. Ready mix concrete is sometimes preferred to on-site concrete mixing because of the accuracy of the mixture and reduced work site confusion. However, using a pre-determined concrete mixture reduces flexibility, both in the supply chain and in the actual components of the concrete. Moreover due to the natural process of hydration of the cement, which obliges to cast concrete in a short time, rural area or inaccessible job sites cannot be reached by truck mixers. This can be solved by batching concrete on site when bags of cement, sand, aggregate, clean water and specific admixtures are available on site. Thank to all these factors, RMC companies can batch concrete right on the pouring site so they can reach places which are too far from their main plants.