عنوان مقاله [English]
نویسندگان [English]چکیده [English]
The mix design of the Ultra-High-Performance Concrete (UHPC) consists of water, microsilica, steel fiber, cement, fine sand, superplasticizer and stone powders such as quartz. The intended UHPC will be constructed using the indigenous materials in Iran which will be subject to investigations regarding the influence of ageing on its compressive strength. Low water-to-cement ratios contribute to high-density concretes exceeding 130MPa in compressive strength. Incorporation of the steel fiber plays its role in enhancing the tensile strength and post-cracking behavior of concrete by bridging and closing the cracks from their initiation until their propagation. Attention should also be given to the application of the highly-reactive microsilica with its high surface energy feature should. In this study, 112 cubic specimens (10 with different steel fiber contents were investigated. Compressive strength tests were carried out on concrete during different stages of ageing. Results revealed an increasing trend for the compressive strength of concrete with the increase in fiber content (5). However, there is an upper limit for the fiber content, e.g. 6% which significantly degrades the performance of concrete beyond this limit, not to mention the challenges that occur in practice in this case. Finally, for specimens constructed with the aforementioned procedure, 90% of the ultimate strengths are obtained after 18 days.