Effects of Nylon Fibre and Concrete Strength on the Shrinkage and Fracture Behaviour of Fibre Reinforced Concrete

Ozsar D. S. , Ozalp F. , Yilmaz H. D. , AKÇAY ALDANMAZ B.

4th International RILEM Conference on Strain-Hardening Cement-Based Composites (SHCC), Dresden, Germany, 18 - 20 September 2017, vol.15, pp.188-194 identifier identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 15
  • Doi Number: 10.1007/978-94-024-1194-2_22
  • City: Dresden
  • Country: Germany
  • Page Numbers: pp.188-194


In this study, mechanical properties, fracture behaviour, and autogenous shrinkage behaviour as well as drying of Nylon (polyamide 6.6) fibre reinforced concretes were investigated. In the first series, 1 volume percent of Nylon macro fibres were added to two concretes with water to cement ratios of 0.35 and 0.42. Then, 0.5 volume percent of micro fibres were added to the concretes with water to cement ratios of 0.35 and 0.42. In the last series, hybrid fibre reinforced concrete with water to cement ratio of 0.42 was produced by adding a mixture of macro (1%) and micro (0.5%) Nylon fibres. It is shown that both the size of the Nylon fibres and water to cement ratio have significant effects on the residual stresses in the post-peak response of fibre reinforced concrete in bending. In concrete with low water to cement ratio and with macro fibres, the cracks usually cut the fibres without pull-out mechanism, and fracture tends to be less ductile in nature. On the other hand, concrete with water to cement ratio of 0.42, the fibre pull-out mechanism was found to be more effective, and steeper gradients of the stress-crack width curves were obtained. It was found that at a constant water to cement ratio the compressive and flexural strengths were higher in concretes with micro fibres than in those with macro fibres. Both of these fibre types had a diminishing effect on the shrinkage of concretes, but it was found that the use of micro Nylon fibres was more effective for mitigating autogenous shrinkage of concrete, especially at early ages.