الفهرس 
Light Weight High Strength ConcreteOnly 14 pages are availabe for public view
 |  | from | 32 |  |  |
| | | from | 32 | | |
Abstract
This study aims to investigate the structural behavior of light weight ferrocement composite concrete beams to be used as a viable alternative to the conventional reinforced concrete beams. Since the use of cementitious composites for various structural applications is becoming more popular with the introduction of new high performance materials, ferrocement laminates are introduced to enhance the overall performance of structures, and to reduce the impact on the environment. The response of concrete for dynamic loading is of interest in a variety of civilian and military applications. characterization of the behavior of concrete under dynamic loading is a prerequisite for the design and analysis of these structures. This paper present the results of a series of experiments conducted to investigate the rate sensitivity and the effectiveness of fiber inclusions in the improvements of fracture toughness of high performance concrete (HPC) beams. Single-edge notched beams (0.5 notch ratio) were loaded in three points bending over a wide range of displacement rates (Do). Load - displacement curves show that their peak is higher as the Do increases, whereas the corresponding displacement is almost constant. Fracture energy, Gf also increases but only under Do beyond a threshold value. The experimental finding of the present work addressed the positive roles of fibers (steel and polypropylene) in improving the performance of concrete under dynamic loading. This thesis presents the results of an extensive experimental program undertaken to optimize compressive strength, ultrasonic pulse velocity (UPV), and abrasion wear of heated high performance concert using Taguchi method and the utility concept. The design of experiments (DOEs) was first carried out by Taguchi method using a standard L25(35) orthogonal array of three factors with five materials parameters levels. The factors considered in this context of HPC were: fiber volume fracture, age time and post-heat temp. The prism specimens having the dimensions of 60x60x300 mm, which reinforced with various volume fractions and left after casting for different age times (7 day, 21 day, and 56 day) then heated up to 200 °C, 400 °C, and 800 °C for a time of 3hrs then they were subsequently tested in the cooled conditions. Based on the experimental results, the materials parameter responses were analyzed. The investigated HPC is a load rate sensitivity material, it resists high load and absorbs more energy under dynamic loading than under static loading. Fibers (basalt and polypropylene) are particularly effective in improving the performance of concrete under dynamic loading. This is attributed to their higher strain capacity and loading bearing capacity in the post cracking zone. The low modulus of elasticity of polypropylene fibers combined with the considerable adhesion in the matrix improved its capacity to stretch during dynamic loading. The research findings along with various mathematical models will provide effective guideline to select parameter settings for achieving desired compressive strength, static elastic modules, flexural strength, ultrasonic pulse velocity, dynamic elastic modulus, and abrasion wear during post-fire residual properties of high performance concrete. This research work will open up further scope to study the performance concrete quality.