International Concrete Abstracts Portal

This paper presents the crack monitoring of reinforced concrete beams strengthened with fiber reinforced polymer (FRP) sheets. Emphasis is placed on the development of a smart FRP bonded material that can measure the crack opening of a reinforced concrete beam strengthened by FRP. The reliability measured by a conventional digital image correlation (DIC) and by the proposed smart FRP is employed to assess the contribution of the FRP to control the crack. The monitoring process is based on a large set of experimental database consisting of 19 test beams. The effect of FRP to control the crack opening is studied depending on the steel ratio, FRP ratio and the level of damaged of RC beams when FRP is applied. The results were compared with the theoretical values of crack width and spacing predicted using the Eurocode 2 (EC2) formula, calibrated for non-strengthened RC elements. The corresponding results were compared in order to clarify the effect of external bonded FRP on the cracking behaviour of RC beams.

Architects, structural engineers, and contractors should work together to ensure that reducing embodied carbon in concrete on every project is a priority. This article sets out the framework for concrete contractors’ participation in smart sustainable concrete construction. It reflects input from the American Society of Concrete Contractors (ASCC) Sustainability Committee.

The damage to infill walls caused by earthquakes often represents a major safety issue in reinforced concrete buildings. For this reason, masonry infill retrofit is increasingly adopted in high seismic hazard countries to increase the in-plane capacity of the walls and to avoid out-of-plane failure modes. On the other hand, the infill strengthening might significantly modify the seismic performance of the buildings, influencing the failure modes and the global ductility. Recent studies assessed that the enhancement of the in-plane strength of the infill can cause brittle failure in lightly shear reinforced columns. In this study, non-linear analyses are performed on reinforced concrete framed buildings to investigate the influence of the infill strengthening and column shear reinforcement on seismic performance. A three-dimensional numerical model is developed to assess the seismic capacity and the failure modes depending on the frame’s and infill’s details. The proposed study aims to encourage a smart design of the infill retrofit, geared toward a global performance enhancement rather than the mere strengthening of the single infill wall.

This work investigates the potential of recycled carbon-based materials, obtained from industrial by-products, for the production of multifunctional cement-based composites (MCC) with self-sensing behavior, usable in structural health monitoring (SHM) systems. As recycled materials, used foundry sand (UFS) and recycled carbon fibers (RCF) have been chosen, whereas graphene nanoplatelets (GNP) and virgin carbon fibers (VCF) have been selected as reference industrial fillers and fibers, respectively. Their effects on OPC-based mortars have been tested in terms of mechanical strength (compressive, flexural), durability (water absorption), microstructure (porosity), and electrical and piezoresistive behavior (resistivity in static and under-load conditions). The results show that the combination of recycled fillers-fibers gives the best results in terms of workability, microstructure, strength, and durability. The worst compressive performances obtained with GNP are related to its hydrophobicity and the related problems in mixing. On the other hand, mixtures with UFS show a low electrical conductivity, but a high sensitivity to deformation (electrical strain-sensing). High-carbon by-products could be a functional, low-cost, and eco-friendly solution to produce high-performance and conductive concretes for self-monitoring systems.

There is a great demand in the world for low-cost and functional pipeline systems due to the renovation requirements of pipes in use and the continuous development of new settlements. Previously used pipeline systems made of steel reinforced concrete are economical and sufficiently resistant. However, due to the corrodibility of steel reinforcement and to enable sufficient crack reduction, large wall thicknesses and thus heavy constructions are required. Textile reinforced concrete (TRC) eliminates these disadvantages by enabling the production of light and thin-walled structures.

The aim of this research is the development of a concept for the realization of smart pipes made of sensory TRC by using the advantages of lightweight, thin-walled structures, focusing on the production process. Based on different warp knitted textile variations with different coating concentrations, preliminary tests were carried out using the fourpoint bending test. As a result of the preliminary tests, the textile variation of counterlaid tricot with a maximum coating concentration was selected as a suitable reinforcing material for the concept development. Concepts for the production of smart TRC pipes are developed accordingly. As a result, a casting mold and process were created which allowed a production with reduced diameter and depth of pores and concentric positioning of the reinforcement structure.