ارائه مدل دو فازی خمیر- دانه برای تعیین نسبت اختلاط بتن های سبکدانه حاوی لیکا

Abstract
In general, methods of lightweight aggregate concrete mix design are not much different with
the ordinary concrete mix designs, except that in LWAC, volumetric method must be used for
determining the amount of aggregates (normal and lightweight). In some countries, the same
mix design of conventional concrete (normal weight) is also used for this purpose. Due to the
specific restrictions of these methods, it is difficult to use them in certain cases where
concrete slump is specified, or high strength concrete is needed.
In this paper, a new method for the mix design of lightweight aggregate concrete has been
proposed using a type of artificial lightweight aggregate (expanded clay, Leca). This approach
is based on two-phased model (particle and matrix), and has better performance compared to
other methods, due to the possibility of considering the properties of cement paste and particle
in terms of access to consistency (slump) and the required strength of the concrete made. Also
in this method, the percentage composition of normal and lightweight aggregates is chosen to
achieve minimum space (porosity), so, the minimum amount of cement paste will be used to
achieve the above requirements, and the economic saving.