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Portland cement comes in a variety of different types.Type II is a moderate sulfate resistant cement, important when concrete is cast against soil that has moderate sulfate levels. Type III is a high early strength cement. It is ground finer and reacts faster than Type I, so the early strength gains are greater.Bleeding in fresh concrete refers to the process where free water in the mix is pushed upward to the surface due to the settlement of heavier solid particles such as cement and water. Some bleeding is normal but excessive bleeding can be problematic.A concrete mixture ratio of 1 part cement, 3 parts sand, and 3 parts aggregate will produce a concrete mix of approximately 3000 psi. Mixing water with the cement, sand, and stone will form a paste that will bind the materials together until the mix hardens.The water–cement ratio is the ratio of the weight of water to the weight of cement used in a concrete mix. A lower ratio leads to higher strength and durability, but may make the mix difficult to work with and form. Workability can be resolved with the use of plasticizers or super-plasticizers.Water cure:The concrete is flooded, ponded, or mist sprayed. This is the most effective curing method for preventing mix water evaporation. Make sure you allow proper time for water curing. Water retaining methods:Use coverings such as sand, canvas, burlap, or straw that are kept continuously wet.Precast concrete is a construction product produced by casting concrete in a reusable mold or “form” which is then cured in a controlled environment, transported to the construction site and lifted into place (“tilt up”). In contrast, standard concrete is poured into site-specific forms and cured on site.The slump test is a means of assessing the consistency of fresh concrete. It is used, indirectly, as a means of checking that the correct amount of water has been added to the mix. The test is carried out in accordance with BS EN 12350-2, Testing fresh concrete.