Authors
Abstract
The study is conducted to perform two goals: The first geal is to produce a
lightweight concrete using major components which are locally available with
some standard admixtures.Many mixtures are prepared using many ratios of
superplasticizer (SP) and silica fume (SF) admixtures to yield a lightweight
aggregate concrete, the effects of using different ratios of these admixtures on unit
weight, compressive strength and flexural strength are studied individually and
accumulatively. The secondis to study the dynamic specifications of normal and
lightweight reinforced concrete beams.
The results showed that the increasing in dosage of superplasticizer (SP) for
(LWAC) increases the density of (LWAC), and the increasing in dosage of silica
fume (SF) decreases the density of (LWAC). The experimental impact tests for
R.C. beams shows that the lightweight R.C. beams have a better response under
impact loading with respect to the maximum dynamic deflection (2.955mm for
normal weight beam and 1.58mm for lightweight beam). Also,Impact force
transferred to supports reactions of lightweight beams is smaller within 45% than
the impact force transferred to reaction of normal weight concrete under the same
impact load, and the time to reach 90% damping equal to 1.223 sec and 1.6 sec for
lightweight and normalweight R.C. beams respectively. Also, the reinforced
concrete beams are tested under repeated impact load up to failure. The tests
showed that the no. of blows to cause first crack for lightweight concrete beams
more than twice of this for normalweight concrete beams.
Keywords
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