in a ready mix concrete plant. Better handling and proper mixing practice will help reduce the consumption of cement by 10 – 12%. The use of admixtures and other cementitious materials will help to reduce the amount of cement as is required to make the desired grade of concrete. Less consumption of cement indirectly results in less environmental pollution. Ready mix concrete manufacture have less dependency on human labor hence the chances of human error are reduced. This will also reduce the dependency on intensive labor. Cracking and shrinkage. Concrete shrinks as it cures. It can shrink inch (1.59mm) over a 10 foot long area (3.05 meters). This causes stress internally on the concrete and must be accounted for by the engineers and finishers placing the concrete, and may require the use of steel reinforcement or pre-stressed concrete elements where this is critical. Access roads and site access have to be able to carry the weight of the ready-mix truck plus load which can be up to 32 tonnes for an eight-wheel 9 m3 truck. (Green concrete is approximately 3,924 pounds per cubic yard, or 2,400 Kg/m3). This problem can be overcome by utilizing so-called "mini mix" trucks which use smaller 4 m3 capacity mixers able to reach more weight restricted sites. Even smaller mixers are used to allow a 7.5 tonne truck to hold approximately 1.25 m3, to reach restricted inner city areas with bans on larger trucks. Metered concrete As an alternative to centralized batch plant system is the volumetric mobile mixer. This is often referred to as on-site concrete, site mixed concrete or mobile mix concrete. This is a mobile miniaturized version of the large stationary batch plant. They are used to provide ready mix concrete utilizing a continuous batching process or metered concrete system. The volumetric mobile mixer is a truck that holds sand, rock, cement, water, fiber, and some add mixtures and color depending on how the batch plant is outfitted. These trucks mix or batch the ready mix on the job site. This type of truck can mix as much or as little amount of concrete as needed. The on-site mixing eliminates the travel time hydration that can cause the transit mixed concrete to become unusable. These trucks are as precise as the centralized batch plant system, since the trucks are scaled and tested using the same ASTM (American standard test method) like all