Fineness test
The fineness of cement has an important bearing on the rate of hydration and hence on the rate
of gain of strength and also on the rate of evolution of heat. Finer cement offers a greater
surface area for hydration and hence faster the development of strength, fig. below. Different
cements are ground to different fineness. The disadvantages of fine grinding is that it is
susceptible to air and early hydration. Increase in fineness of cement is also found to increase
the drying shrinkage of concrete.
Fineness is necessary to cover surfaces of the fine aggregate particles at better manner – leading
to better adhesion and cohesion between cement mortar constituents.
An increase in the fineness of cement, both consistency of cement and workability of concrete
increase. Increase in consistency means increase in water demand to get cement paste of
standard consistency while increase in workability means increase in flow ability at the same
water/cement ratio. In other words decrease in water demand to get the same workable concrete.
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
|