Mechanical properties and dynamic response of lightweight reinforced concrete beam

الملخص EN

The study is conducted to perform two goals: The first geal is to produce a light weight concrete using major components which are locally available with some standard admixtures.

Many mixtures are prepared using many ratios of super plasticizer (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 seconds to study the dynamic specifications of normal and light weight reinforced concrete beams.

The results showed that the increasing in dosage of super plasticizer (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 (2.955 mm 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 light weight and normal weight 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 normal weight concrete beams.