Self-compacting concretes (SCC) are highly fluid concretes that can flow and be placed in formwork under their own weight without the requirement of internal or external energy. This fluidity is obtained with the use of high paste volume and superplasticizer. The paste of SCC is made principally of cement, which is the most expensive component of concrete. As a result, the production cost of SCC is higher than conventional concrete. However, to make the manufacture of SCC more practical and economical, the binder is often a binary, ternary even quaternary compound: Portland cement mixed with mineral additions. The primary aim of this work is to study the effect of incorporating the marble powder as a supplementary cementations material on the rheological and mechanical properties of SCC. The fresh properties were measured using the slump flow, J-Ring, V-funnel, and modified slump flow. The properties of hardened SCC such as strengths and ultrasonic pulse velocity (UPV) were determined at age of 3, 28, and 90 days. The results have shown that using of marble powder in SCC enhances their fresh properties. At hardened state, the incorporation of marble powder decreases the mechanical strengths and UPV. It can be noted that it is possible to produce an economical SCC when the cement is partially substituted by the marble powder.

This paper presents the results of an experimental study that investigated the rheological and mechanical properties of self-compacting mortars incorporating fine dune sand (DS), which has a tight Particle size distribution. Mortar mixtures were prepared with crushed sand (CS) or river sand (RS) in which the fine aggregates were replaced partially by different percentages of DS of 0, 25, 50, 75 and 100%. The effect of DS on the fresh mortars properties was studied using the mini-slump flow, V-funnel flow time and viscosity measurements tests. Compressive strength and flexural strength were determined at age of 3, 7 and 28 days. Experimental results indicate an improvement in fresh rheological without reducing in mechanical properties of self-compacting mortars when fine aggregates were replaced partially with DS (50%). However, at high-level DS replacement (75%) the slump flow decreases. The replacement of the DS to the CS or to the RS shows an increase in the mixture viscosity. In general, the compressive and flexural strength were not significant affected with an increase in DS replacement. Finally, based on the results obtained in this investigation, DS may provide a readily available alternative material as fine aggregates in mortar application.

The effect of using calcined bentonite (CB) as a partial replacement for Ordinary Portland cement (OPC) in self-compacting mortar (SCM) is investigated. The pozzolanicity of this calcined clay is evaluated using the strength activity index and TG/ATD analysis. The cement in SCM has been replaced with CB at 0, 5, 10, 15, 20, 25 and 30% by mass of cement. The effect of CB on fresh SCM properties is examined using mini-slump flow and V-funnel flow time. The compressive strength is determined at the age of 3, 7 and 28 days, and the ultrasonic pulse velocity (UPV), hardened density and water absorption are determined at the age of 28 days. The behaviour of SCM exposed to high temperature is also studied. The results indicate that CB significantly decreased the flowability of SCM, but these results are good enough for SCM and SCC production. Incorporating 10 and 15% of CB improves the compressive strength and UPV. Water absorption tends to increase slightly with an increase in CB content and there is a decrease in density as the amount of CB increases. SCM containing CB is stronger when exposed to high temperature than those exposed to normal temperature (23 °C).

The use of porous concrete in various infrastructure applications such as pavements, infiltration beds, and low-volume load areas is increasingly encouraged due to its environmental benefits. The performance of porous concrete is strongly influenced by its pore structure and overall porosity. Researchers have employed multiple methodologies to characterise pore size and distribution, and to assess their effects on permeability, hydraulic conductivity, and compressive strength. This review investigates several pore measurement techniques aimed at improving both the hydraulic and mechanical performance of porous concrete. Among these, image analysis emerges as the most accurate method for assessing porosity distribution, offering higher resolution and fewer limitations compared to traditional techniques. Despite these advancements, a debate remains regarding the relative importance of effective porosity versus total porosity. This work comprehensively evaluates and synthesises existing methods for pore structure analysis, thereby enhancing our understanding of how porosity influences concrete behaviour. The findings indicate that effective porosity alone is insufficient to predict hydraulic conductivity, whereas total porosity has a considerable effect on compressive strength. This insight can be used to optimise the balance between strength and permeability in porous concrete, supporting its broader implementation as a sustainable construction material.

Near surface mounted (NSM) carbon fibers reinforced polymer (CFRP) reinforcement is one of the techniques for reinforcing masonry structures and is considered to provide significant advantages. This paper is composed of two parts. The first part presents the experimental study of brick masonry walls reinforced with NSM CFRP strips under combined shear-compression loads. Masonry walls have been tested under vertical compression, with different bed joint orientations 90° and 45° relative to the loading direction. Different reinforcement orientations were used including vertical, horizontal, and a combination of both sides of the wall. The second part of this paper comprises a numerical analysis of unreinforced brick masonry (URM) walls using the detailed micro-modelling approach (DMM) by means of ABAQUS software. In this analysis, the non-linearity behavior of brick and mortar was simulated using the concrete damaged plasticity (CDP) constitutive laws. The results proved that the application of the NSM-CFRP strips on the masonry wall influences significantly strength, ductility, and post-peak behavior, as well as changing the failure modes. The adopted DMM model provides a good interface to predict the post peak behavior and failure mode of unreinforced brick masonry walls.

This paper presents an experimental and numerical study into the shear response of brick masonry triplet prisms under different levels of precompression, as well as samples reinforced with carbon fiber-reinforced polymer (CFRP) strips. Masonry triplets were constructed with two different mortar mix ratios (1:1:3 and 1:1:5). In this study, finite element models for the analysis of shear triplets are developed using detailed micro-modelling (DMM) approach and validated with the experimental data. The failure mechanisms observed in the masonry triplets were simulated using a coupled XFEM-cohesive behaviour approach in ABAQUS finite element software. The nonlinear behaviour of mortar and brick was simulated using the concrete damaged plasticity (CDP) constitutive laws. The cohesive element with zero thicknesses was employed to simulate the behaviour of the unit–mortar interfaces. The extended finite element method (XFEM) was employed to simulate the crack propagation in the mortar layer without an initial definition of crack location. CFRP strips were simulated by 3D shell elements and connected to masonry elements by an interface model. The changes in failure mechanism and shear strength are calculated for varying types of mortar and fiber orientation of CFRP composite. Based on this study, it was concluded that the ultimate shear strength of masonry triplets is increased due to the external bonding of CFRP strips. The performance of masonry specimens strengthened with CFRP strips is assessed in terms of gain in shear strength and post-peak behaviour for all configurations and types of mortar considered. The comparison of FE and experimental results proved that the models have the potential to be used in practice to accurately predict the shear strength and reflect damage progression in unreinforced and CFRP-reinforced masonry triplets under in-plane loading, including the debonding of the CFRP reinforcement. Additionally, XFEM was found to be a powerful technique to be used for the location of crack initiation and crack propagation in the mortar layer.