There are various benefits to ultra-high-performance fiber-reinforced concrete ‎‎(UHPFRC). However, using a lot of cement in this type of concrete has a severe disadvantage since it causes pollution and several environmental concerns. Therefore, another type of concrete that achieves the same superior properties as UHPFRC while using less cement in the mixture should be considered. This research examined replacing cement with fly ash to produce environmentally friendly concrete called Green-UHPFRC. The impact of utilizing G-UHPFRC on the flexural behaviour of thirteen beams was investigated experimentally and numerically under repeated loads. The major parameters of the study were fly ash replacement ratios of 15%, 30%, and 45% and adding steel fiber to mixes with ratios of 1, 2, 3, and 4%. The tested beams were compared to the control beam in their backbone and hysteresis curves, failure load, crack propagation and failure modes, energy dissipation, stiffness degradation, and ductility index. From the results obtained, environmentally friendly concrete (G-UHPFRC) can be produced by replacing cement with fly ash up to 45% and adding 2% steel fiber without affecting the bending performance of beams made of G-UHPFRC compared to those made of UHPFRC.

Nowadays, producing eco-friendly concretes by reducing the usage of high volumes of Portland cement is a global aim. Ultra-High Performance Fiber Reinforced Concrete (UHPFRC) involve using high volumes of Portland cement, which leads to high heat of hydration as well as high carbon emissions that enhance global warming. Therefore, researchers worldwide are interested in producing and assessing Green Ultra-High Performance Fiber Reinforced Concrete (GUHPFRC) which is the main focus of this paper. In this study, thirteen mixtures of such concretes are prepared to study the effect of using Fly Ash (FA) class F, as a Portland cement substitute by volume. The Fly Ash ratios of 15%, 30% and 45% are used to study the effect on the compressive strength of UHPFRC. The paper also focuses on incorporating both corrugated and end hook steel Fibers in the mixes with ratios (1%, 2%, 3% and 4%) to compensate for the decrease in compressive strength of concrete due to the replacement of cement by FA. The results showed that the substitution of 45% of the Portland cement with FA along with the incorporation of steel Fibers in the UHPFRC can be effective without any compressive strength loss.