Polyolefin Macro - Monofilament Fibre Reinforced High Performance Concrete

The experimental investigation and theoretical analyses presented in this thesis deal with the development of Polyolefin Macro-Monofilament Fibre Reinforced High Performance Concrete (PMMFRHPC) is presented in this thesis. The scope of its structural applications is also highlighted at the end of the thesis. The concrete mix adopted in this investigation was designed based on the guidelines of ACI 211.4R-'08, 'Guide for Selecting Proportions for High Strength Concrete with Portland and Other Cementitious Materials. PMMFRHPC mixes were produced by incorporating the mineral admixtures such as fly ash and metakaolin (10% each) and by adding Polyolefin Macro-Monofilament (PMM) Fibres at different volume fractions from 0.1% to 0.3 percent. Five different concrete mixes namely, one without admixtures and fibres, one with admixtures and without fibres and the remaining three mixes with admixtures containing 0.1, 0.2 and 0.3 percentages of fibres were considered in this investigation. The workability of concrete mixes was measured using slump test. The mechanical properties such as cube compressive strength at the age of 28, 56 and 90 days, and cylinder splitting tensile strength, modulus of rupture, modulus of elasticity and Poisson's ratio at the age of 28 days were determined. Totally 105 hardened concrete specimens were cast for the above five types of concrete mixes. For PMMFRHPC, empirical relationships were developed to predict the splitting tensile strength and modulus of rupture from the 28 days compressive strength. Mathematical equations were also developed to predict the mechanical properties in terms of quantity of constituent materials. In addition to that , 306 specimens were cast and tested to determine the durability of PMMFRHPC through the measurement of voids permeability, water absorption, permeability, acid resistance, impact resistance, drying shrinkage, rapid chloride penetration and corrosion resistance at the age of 28, 56, 90 and 120 days. The correlations were obtained for durability studies with respect to age, volume fraction of fibre and compressive strength. Mathematical relations have been developed to predict the durability properties in terms of quantity of constituent materials. In order to investigate the possibility of using PMMFRHPC for structural applications, ten reinforced concrete beams of size 100 mm x 200 mm x 1700 mm were cast and tested. Out of these ten beams, five beams were tested by gradually applying symmetrical two point loading up to failure and the deformation characteristics have been studied by measuring deflections and observing the crack patterns. The applicability of Whitney's Theory to predict the ultimate flexural strength of PMMFRHPC beams has been examined. Using the properties of concrete mixes theoretical deflections have been calculated by conjugate beam theory and compared with the experimental values. The influence of fibre content on energy absorption capacity and toughness index was also evaluated. The displacement ductility and the rotation ductility factors were also derived. Finite Element Analysis (FEA) using 'ANSYS' 12.0 software has been carried out and the outcome of the analysis was compared with experimental values. The remaining five reinforced concrete beams were tested by applying cyclic loading. Forty five percentage of static ultimate load was considered for cyclic loading. The number of cycles withstood by each beam before complete collapse was recorded and the crack patterns were observed. The effect of fibre content on the energy absorption capacity and the structural behaviour was also studied.