INFLUENCE OF STEEL FIBRE ON CONCRETE
Advancements in technology enhances not only human comforts but also damages the environment. Use of steel fibre has become popular and safe now. Today the construction industry is in need of finding cost effective materials for increasing the strength of concrete structures. Hence an attempt has been made in the present investigations to study the influence of crimpled steel fibre concrete at a dosage of 0.8 % volume of concrete. Experimental investigation was done using M20 mix and tests were carried out as per recommended procedures by relevant codes. The study parameters of this investigation included compressive strength, split tensile strength and flexural strength of conventional and fibre reinforced concrete. The results indicated that the compressive, split tensile and flexural strength of fibre reinforced concrete is increased by 32.14%, 52.38%, 12.68% respectively when compared to the conventional concrete.
Validation of Using Mixed Iron and Plastic Wastes in Concrete
Metals and plastics waste materials create serious environmental problems, mainly owing to the inconsistency of the wastes streams. The purpose of this paper is to evaluate the possibility of using mixed iron filings and granulated plastic waste materials simultaneously to partially substitute the fine aggregate in concrete composites. Type I Portland cement was mixed with the aggregates to produce the concrete composites. Three weight fractions (30, 40, and 50%) of iron filings waste aggregate were used with 5% of granulated plastic waste. The slump, compressive and flexural strengths as well as the fresh and hard density of the concrete mixtures were determined. The results of the mechanical properties were analyzed in comparison to the control specimens. The main findings of this investigation revealed that the mixture of iron filings and plastic waste materials could be used successfully as partial substitutes of sand in concrete composites. Increasing the granulated plastic waste in the mixed aggregate waste materials up to 10% did not seriously hinder the strength properties of the waste-concrete specimens.
Experimental study on bond behavior between high-strength grout and deformed steel bars
Abstract Engineers use high-strength grout to connect precast concrete members for its low shrinkage and good fluidity. This paper designed 87 central pull-out specimens using the control variable method to investigate the influence of factors on the rebar-grout bond property such as compressive strength, steel grade, bar diameter, transverse stirrups, and bond length. The test result showed that improving grout compressive strength (85.8 MPa–122.7 MPa) cannot improve the bond strength, which was different from the previous conclusions of concrete pull-out tests. Simplified formulas were presented for calculating the characteristic values of bond strength, residual strength, peak slip, and relative slip of load-holding platform based on parameter analysis. Then, a constitutive model was proposed to predict the full-range bond stress-slip curve of high-strength grout and steel bar specimens from bearing to failure. Finally, FEA models were established to evaluate the applicability and accuracy of the constitutive model.