Citation: Saeed, H.Z.; Saleem, M.Z.; Chua, Y.S.; Vatin, N.I. Research on Structural Performance of Hybrid Ferro Fiber Reinforced Concrete Slabs. Materials 2022, 15, 6748. https://doi.org/10.3390/ ma15196748 Academic Editor: Angelo Marcello Tarantino Received: 18 July 2022 Accepted: 17 August 2022 Published: 29 September 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). materials Article Research on Structural Performance of Hybrid Ferro Fiber Reinforced Concrete Slabs Hafiz Zain Saeed 1, * , Muhammad Zubair Saleem 2 , Yie Sue Chua 1, * and Nikolai Ivanovich Vatin 3 1 School of Engineering, Monash University, Jalan Lagoon Selatan, Bandar Sunway 47500, Malaysia 2 Department of Civil Engineering, University of Engineering and Technology, Taxila 47080, Pakistan 3 Peter the Great Saint Petersburg Polytechnic University, 195251 Saint Petersburg, Russia * Correspondence: hafiz.saeed@monash.edu (H.Z.S.); chua.yiesue@monash.edu (Y.S.C.) Abstract: Reinforced concrete structures, particularly in cold areas, experience early deterioration due to steel corrosion. Fiber-Reinforced Concrete (FRC) is an emerging construction material and cost-effective substitute for conventional concrete to enhance the durability and resistance against crack development. This article examines the structural performance of hybrid ferro fiber reinforced concrete slabs (mix ratio of mortar 1:2) comprising silica fume, layers of spot-welded mesh and different ratios of polypropylene fibers. The ferrocement slabs are compared with a conventional Reinforced Cement Concrete (RCC) slab (mix ratio of 1:2:4). The experimental work comprised a total of 13 one-way slabs, one control specimen and three groups of ferrocement slabs divided based on different percentages of Poly Propylene Fibers (PPF) corresponding to 0.10%, 0.30% and 0.50% dosage in each group. Furthermore, in each group, the percentage of steel ratio in ferrocement slabs varied between 25% and 100% of the steel area in the reinforced concrete control slab specimen. For evaluating the structural performance, the observation of deflection, stress-strain behavior, cracking load and energy absorption are critical parameters assessed using LVDTs and strain gauges. At the same time, the slabs were tested in flexure mode with third point loading. The experimental results showed that the first cracking load and ultimate deflection for fibrous specimens with 0.5% fiber and 10% silica fume increased by 15.25% and 13.2% compared with the reference RCC control slab. Therefore, by increasing the percentage of PPF and steel wire mesh reinforcement in the ferrocement slab, the post-cracking behavior in terms of deflection properties and energy absorption capacity was substantially enhanced compared to the RCC control slab. Keywords: fiber-reinforced concrete slab; deflection; failure; stress-strain curve 1. Introduction The construction industry is facing challenging civil engineering structures and ever- increasing material demands. Concrete contains about 10% by weight of cement [1]. Its performance is adversely affected due to micro-cracks formation before the application of loads, resulting in limited ductility, low tensile strength and little resistance against crack propagation [2,3]. Low tensile strength in concrete also leads to a brittle failure under the tension of about one-tenth of its compressive strength. Moreover, the manufacturing process of cement results in the emission of greenhouse gases; therefore, there is a need to develop and replace the conventional building construction material with an alternative environmentally friendly material [4,5]. To avoid higher costs from importing the mate- rials, local materials are usually preferred for constructing floor and roofing systems in developing countries. The ductility of the concrete can be improved by adding fibers as a replacement for cement [6]. Ferrocement material, also known as thin reinforced concrete, is a versatile building construction material [7–9]. Due to comparatively better impact resistance, ductile performance, strength, and the readily casting feature, among other types of concrete, ferrocement material is considered an economical alternative for roofing Materials 2022, 15, 6748. https://doi.org/10.3390/ma15196748 https://www.mdpi.com/journal/materials