This work developed experimental tests and numerical models able to represent the mechanical behavior of prisms made of ordinary and high strength concrete blocks. Experimental tests of prisms were performed and a detailed micro-modeling strategy was adopted for numerical analysis. In this modeling technique, each material (block and mortar) was represented by its own mechanical properties. The validation of numerical models was based on experimental results. It was found that the obtained numerical values of compressive strength and modulus of elasticity differ by 5% from the experimentally observed values. Moreover, mechanisms responsible for the rupture of the prisms were evaluated and compared to the behaviors observed in the tests and those described in the literature. Through experimental results it is possible to conclude that the numerical models have been able to represent both the mechanical properties and the mechanisms responsible for failure.
1 December 2018 in Revista IBRACON de Estruturas e Materiais
Environmentally eco-efficient concrete is currently a popular choice of construction material. Reviewing relevant literature indicates that heating of cement paste can remove hydrating water, and that quartz sand of appropriate granulometry can act as a supplementary cementitious material; however, there have been virtually no reports on the reuse of these materials as alternative binders. This work evaluates the phases present in cementitious compounds produced with binders obtained by thermomechanically treating cement pastes with and without a 15% substitution of quartz sand powder (specific surface area 37.4 m²/g), referred to as RCQ and recycled cement RC, respectively. Testing included thermogravimetric analysis (performed with stripped gases), X-ray diffraction, and scanning electron microscopy with phase identification. The obtained data indicated RC cement paste possesses a predominantly ettringite microstructure, whereas the presence of calcium hydroxide and hydrated calcium silicate predominates in RCQ paste.
The structural performance of civil engineering infrastructures exposed to elevated temperatures has been investigated in many recent works. Some of these studies evaluated the residual mechanical behavior of masonry prisms subjected to high temperatures, as these specimens are simplified models (2–5 units in height) that can be easily produced and tested, in terms of operational and economic factors. However, there is no previous literature review on the mechanical properties of fire-damaged masonry prisms. Therefore, this paper presents an investigation of the current state-of-the-art on this topic. It provides a careful review of recent knowledge on the failure mechanisms, residual compressive strength, modulus of elasticity, and stress–strain behavior of masonry prisms made with different types of units, mortars, and/or grout after exposure to different types of thermal treatments. Based on the revised information, future research directions on the scientific field of masonry infrastructures are reported.
1 October 2016 in Revista IBRACON de Estruturas e Materiais
This paper aims to evaluate the interaction between structural masonry walls made of high performance concrete blocks, under vertical loads. Two H-shaped flanged wall series, all full scale and using direct bond, have been analyzed experimentally. In one series, three flanged-walls were built with the central wall (web) supported and, in the other one, three specimens were built without any support at the central web. The load was applied on the central wall and vertical displacements were measured by means of displacement transducers located at eighteen points in the wall-assemblages. The results showed that the estimated load values for the flanges were close to those supported by the walls without central support, where 100% of the load transfer to the flanges occur. The average transfer load rate calculated based on the deformation ratio in the upper and lower section of the flanged-walls, with the central web support, were 37.65% and 77.30%, respectively, showing that there is load transfer from the central wall (web) toward the flanges, particularly in the lower part of the flanged walls. Thus, there is indication that the distribution of vertical loads may be considered for projects of buildings for service load, such as in the method of isolated walls group. For estimation of the failure load, the method that considers the walls acting independently showed better results, due to the fact that failure started at the top of the central wall, where there is no effect of load distribution from the adjacent walls.
This article presents numerical models for unbraced steel frames filled with structural masonry under cyclic loads, offering insights into their behavior and design potential. Using simplified micro-modeling in ABAQUS with the Concrete Damage Plasticity (CDP) model, the study accurately represents masonry interactions and shows strong agreement with experimental data (R2 = 0.977). Results indicate that the fracture energy of laying joints and the friction coefficient between masonry and steel frames critically influence displacement, collapse mechanisms, and overall stiffness. Key findings reveal that the masonry infill increases frame stiffness by approximately ten times compared to the empty frame, reducing lateral deformations to less than 0.17% of the drift ratio. Masonry infills significantly enhance frame rigidity, acting as efficient bracing elements and reducing deformations, which is particularly valuable for seismic-resistant design. The research confirms the reliability of the CDP model for complex masonry behavior, validates simplified approaches for reduced computational cost, and highlights the need to incorporate friction effects in simulations. These findings provide a basis for future technical standards and offer practical strategies for engineers working with composite steel–masonry systems.