CE5215-Theory and Applications of Cement Composites Dr. T. P. Tezeswi Assistant Professor, Dept. of Civil Engineering NIT-Warangal Email: [email protected]
Chapter - 4Cement composites Types of Cement Composites-Terminology
Classification of Cement Composites Introduction to Fiber Reinforced Cement Materials Ref: Matsumoto & Mihashi ,2003 Since ancient times, fibers have been used to reinforce brittle materials. Straw was used to reinforce sun-baked bricks, and horsehair was used to reinforce masonry mortarand plaster. In more recent times, large scale commercial use of asbestos fibers in a cement paste matrix began with the invention of the Hatschek process in 1898. Asbestoscement construction products are widely used throughout the world today. However, primarily due to health hazards associated with asbestos fibers, alternate fiber types were introduced throughout the 1960s and 1970s. In modern times, a wide range of engineering materials (including ceramics, plastics, cement, and gypsum products) incorporate fibers to enhance composite properties. The enhanced properties include tensile strength, compressive strength, elastic modulus, crack resistance, crack control, durability, fatigue life, resistance to impact and abrasion, shrinkage, expansion, thermal characteristics, and fire resistance.
Classification of Cement Composites •Fiber reinforced concrete (FRC) is concrete made primarily of hydraulic cements, aggregates, and discrete reinforcing fibers. •Fibers suitable for reinforcing concrete have been produced from steel, glass, and organic polymers (synthetic fibers). •Naturally occurring asbestos fibers and vegetable fibers, such as sisal and jute, are also used for reinforcement. •The concrete matrices may be mortars, normally proportioned mixes, or mixes specifically formulated for a particular application. •Generally, the length and diameter of the fibers used for FRC do not exceed 3 in. (76 mm) and 0.04 in. (1 mm), respectively. Ref: State-of-the-Art Report on Fiber Reinforced Concrete, ACI 544.1R-96 (reapproved 2003)
Classification of Cement Composites Ref: Matsumoto & Mihashi ,2003
Classification of Cement Composites Ref: State-of-the-Art Report on Fiber Reinforced Concrete, ACI 544.1R-96 (reapproved 2003) Fiber-reinforced vs conventionally reinforced concrete Unreinforced concrete: low tensile strength, low strain capacity at fracture.