Improving Strengths of Porcelanite Aggregate Concrete by Adding Chopped Carbon Fibers

Abstract

In this work chopped carbon fibers are used to improve tensile strength of Porcelanite lightweight aggregate concrete. Silica fume was added in order to improve the mixes compressive strength. Silica fume increase water demand and using fibers reduce workability, to improve workability and decrease water demand high rang super plasticizers are used. The results showed that compressive strength, splitting tensile strength, modulus of elasticity of carbon fibers Porcelanite lightweight aggregate concrete increase with increasing of carbon fiber up to 2% compared to reference Porcelanite lightweight aggregate concrete without fibers. The percentages of increasing were 14.40%, 68.00%, and 10.66% for compressive strength, splitting tensile strength, and modulus of elasticity, respectively. Flexural Strength continues in increase with increase of fibers. The dry unite weight of mixes with chopped fiber decrease with increase of fiber percentage. Besides the chopped carbon improved the ductility of Porcelanite lightweight aggregate concrete and that clear from stress-strain relationship. AL-Rawi [4] investigated the properties of Porcelanite concrete, with Cement content between 272-687 kg/m3, water cement ratios from 0.65 to 1.6, a strength ceiling up to 32 MPa with an air dry density of 1815 kg / m3 were observed. While AL-Dhaher [5] produced lightweight concrete using Porcelanite with density between 1400–1960 kg/m3 and 28 days compressive strength between 13.0–22.4 MPa. Al-Duleimy[6] studied the effect of addition of superplasticizer and SBR on some properties of Porcelanite lightweight aggregate concrete . A density and compressive strength ranging between 1965.05–1818 kg/m3 and 17.08 – 34.8 MPa at 28 days was observed using cement content of 550 kg/m3. Many other investigations were made and this work is part of continuing research on the subject of application of Porcelanite concrete.