STRUCTURAL BEHAVIOR OF NO FINE CONCRETE AND LIGHTWEIGHT AGGREGATE CONCRETEREINFORCED WITH STEEL FIBERS.

Abstract

Due to low values of mechanical properties of lightweight concrete , lightweight concrete is rarely used in structural members in buildings or structures , the lowest value of compressive strength can be used for concrete is 17 MPa, thus this investigation deals with improving the mechanical properties of two types of lightweight concrete , the first type is lightweight aggregate concrete (LWAC), and the second is no-fines concrete (NFC).The results show that adding steel fibers lead to high increment in flexural and tensile strength in NFC, the flexural strength increased from low value of 1.78 to 6.5MPa(more than 3 times) , the compressive strength also increased but less than the increment in flexural strength . compressive strength increased from 13.6 to 26.1 MPa (doubled) for optimum percentage of steel fiber which was 2.5% and also the study show increment in all mechanical properties in LWAC concrete when adding steel fibers.