This paper determines the effect of discrete fibers on the elastic modulus of concrete and cement composites. Five types of discrete fibers consisting of steel, polypropylene, macro-polyolefin, polyvinyl alcohol (PVA), and basalt fibers were investigated. Results show that discrete fibers had little effect on elastic modulus for fiber-reinforced concrete (FRC) with coarse-to-fine aggregate ratio (C/S) greater than 1. However, for FRC with C/S smaller than 1 and fiber-reinforced cement composites (FRCCs), discrete fibers reduced the elastic modulus. Accordingly, a new elastic modulus equation is proposed to better estimate the elastic modulus of FRC with a maximum fiber volume fraction of 10%. The proposed equation was compared with existing equations from other codes, including American, Japanese, Korean, Norwegian, and European codes, as well as equations proposed by other researchers. These equations were evaluated using more than 400 data points taken from the experimental program and other literatures. The proposed equation provides the most accurate prediction for the elastic modulus of FRC and FRCC with a coefficient of variation of 15% as compared to 32% using ACI 318 equation for C/S ≤ 1.

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Rigid pavements are increasingly becoming a primary pavement type for highways under heavy traffic loading due to their long service life and less frequent requirements for maintenance compared to flexible pavements. The behaviour of a rigid pavement during service life is affected by several parameters such as applied loading features, pavement properties, environmental effects, and pavement foundation properties, which must be taken into account in the analysis and design of rigid pavements. The pavement foundation consists of base, subbase, and subgrade layers, all of which play substantial roles in the long-term performance of the rigid pavement. With the development of computer capacity, the three-dimensional finite element method (3D-FEM) has become a widely utilized tool for analysis of concrete structures such as pavements as it overcomes the limitations of analytical solutions. The main objective of this research is to evaluate the effects of pavement foundation characteristics on rigid pavement response using EverFE software. The parameters examined in this study included the thickness and properties of each layer of the pavement foundation. The analysis results revealed that, generally, stresses and settlements within rigid pavement are considerably reduced when a stiff or thick foundation is used. The analysis of results also showed that the tension bending stresses in the base layer decreased significantly with increases in the thickness of the base layer. It was also found that the addition of a subbase layer within the pavement foundation produced a significant reduction in the tension bending stresses in pavement and base layers with no in compression stresses in both layers noted.

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The effect of replacing the conventional coarse aggregate with wood shavings was evaluated relative to the 28-day compressive strength of the concrete. Six groups were studied: group-1 represented the normal concrete (NC-CTRL1), group-2 (TW-CTRL2) comprised the specimens that had the replacement of the coarse aggregate with raw wood shavings, group-3, group-4, group-5, and group 6 represented the specimens that had the coarse aggregate as coated (treated) wood shavings with cement paste (group-3 and -4) and with tile adhesive paste (group-5 and -6), with and without the effect of the emulsifier, respectively. The density of the TW-CTRL2 concrete was 31.4% lighter than NC-CTRL1. However, the compressive strength of TW-CTRL2 was 75% of the NC-CTRL1, but within the acceptable limits stated in ASTM standards. The findings of this study showed a potential to use the produced concrete as concrete masonry unit when compared with the values reported in previous studies. Compared with TW-CTRL2, the compressive strength increased 45% and 20% for the coated wood shavings with cement and tile adhesive pastes, respectively. The effect of using the emulsifier in the coating process of the wood shavings increased the compressive strength by 20%, and reduced the voids of the concrete by 3%.