Diagonal Tensile Test on Masonry Panels Strengthened with Textile-Reinforced Mortar

This study presents the results of an experimental and numerical program carried out on unreinforced masonry panels strengthened by textile-reinforced mortar (TRM) plastering. For this purpose, five panels were constructed, instrumented and tested in diagonal shear mode. Two panels were tested as reference. The first reference panel was left unstrengthened, while the second one was strengthened by a traditional self-supporting cement mortar matrix reinforced with steel meshes. The remaining three panels were strengthened by TRM plastering applied on one or both faces and connected with transversal composite anchors. The numerical and the experimental results evidenced a good effectiveness of the TRM systems, especially when applied on both panel facings

COMPOSITE STRENGTHENING SOLUTIONS FOR REINFORCED CONCRETE LOAD BEARING ELEMENTS

The results of a complex research and development program relating to the use of fiber reinforced polymeric composite strengthening solutions carried out at the Faculty of Civil Engineering and Building Services Iasi, are presented in this paper. The program has included the conceiving of the structural rehabilitation systems, the detailing and experimental testing of some solutions applied to reinforced concrete beams, slabs and columns (with circular and square cross-section). An efficient use of the component materials to improve the structural performance of the studied reinforced concrete element has been the main target of the research program. The main benefits resulted from the research program refer to the increase of the load capacities, the improvement of the structural response of all strengthened elements and a better control of the failure modes

Microstructure and Mechanical Properties of Cost-Efficient 3D Printed Concrete Reinforced with Polypropylene Fibers

Studying emerging and cutting-edge digital construction techniques, especially the utilization of 3D printing for concrete/mortar materials, holds significant importance due to the potential benefits that these technologies might offer over the traditional approach of casting concrete in place. In this study, a mixture composed of Portland cement, water, sand, limestone filler and polypropylene fibers was utilized for 3D printed concrete production towards the sustainable constructions approach. The benefits that sustain this statement include reduced construction time and material requirements, diminished error and cost, increase in construction safety, flexibility of architectural design, and improved quality with much less construction cost and waste. The microstructure, fresh and hardened mechanical properties of the polypropylene fiber reinforced 3D concrete were investigated. The results indicated that it is essential to attain a slump measurement of approximately 40 mm and a slump flow within the range of 140 to 160 mm, as stipulated by relevant standards (ASTM C1437 and C230/C230 M), in order to create a 3D concrete mixture suitable for extrusion. Also, the effects of printing parameters, fiber dosage, material composition, and other factors on the 3D printed concrete strength were discussed, and the corresponding adjustments were addressed

Influence of Woven-Fabric Type on the Efficiency of Fabric-Reinforced Polymer Composites

The greatest advantage of fiber-reinforced composite materials is the freedom to tailor their strength and stiffness properties, while the most significant disadvantage consists in their high costs. Therefore, the design process and especially the optimization phase becomes an important step. The geometry of the fabric of each lamina as well as their stacking sequence need to be carefully defined, starting from some basic geometric variables. The input parameters are the widths and the heights of the tows, the laminate-stacking sequence and the gaps between two successive tows or the height of the neat matrix. This paper is a follow-up to a previous work on using and improving an in-house software called SOMGA (Satin Optimization with a Modified Genetic Algorithm), aimed to optimize the geometrical parameters of satin-reinforced multi-layer composites. The final goal is to find out the way in which various types of woven fabrics can affect the best possible solution to the problem of designing a composite material, able to withstand a given set of in-plane loads. The efficiency of the composite structure is evaluated by its ultimate strains using a fitness function that analyses and compares the mechanical behavior of different fabric-reinforced composites. Therefore, the ultimate strains corresponding to each configuration are considered intermediate data, being analyzed comparatively until obtaining the optimal values. When the software is running, for each analysis step, a set of intermediate values is provided. However, the users do not have to store these values, because the final result of the optimization directly provides the composite configuration with maximum efficiency, whose structural response meets the initially imposed loading conditions. To illustrate how the SOMGA software works, six different satin-woven-fabric-reinforced composites, starting from plain weave (satin 2/1/1), then satin 3/1/1, satin 4/1/1, satin 5/1/1, satin 5/2/1 and finally satin 5/3/1, were evaluated in the SOMGA interface. The results were rated against each other in terms of the composite efficiency and the case characterized by minimal reinforcement undulation (thinnest laminate) were highlighted