بهبود مشخصات بتن سبکدانه موجود در ایران: بررسی مشخصات مکانیکی و منحنی تنش-کرنش

The potential use of leca and scoria aggregates available in Iran to produce high strength lightweight concrete has been studied. As a result of various concrete mixes with different lightweight aggregate amount, and using normal techniques, it was possible to obtain high quality lightweight concrete which is suitable for application in reinforced and prestressed concrete structures, with a compressive strength higher than 40MPa at 28 days. In order to investigate the mechanical short term properties of this type of high strength concrete, different tests had done. The properties obtained include unit weight, compressive strength, splitting tensile strength, static modulus of elasticity and poisson's ratio. And, some relationships were given to estimate modulus of elasticity and splitting tensile strength of these concretes based on their compressive strength. The mechanical properties were improved by reducing the amount of lightweight aggregate. The results show that both scoria and leca were effective in improving the mechanical properties, but scoria could reach superior limits. Stress- strain curves of investigated concretes were studied and some recommendations are presented for estimating the curves. Based on results, curves were almost linear in ascending and descending branch.