The thermal conductivity (k-value) of cement-based materials like concrete is an important factor when considering the amount of heat transfer through conduction. The amount of heat loss through walls and roofs has a direct effect on the energy consumption of buildings. The steady state and transient methods are considered the two main thermal conductivity measurement approaches. The moisture content, temperature, type of aggregate, type of cementitious material and density of concrete are influential factors on the thermal conductivity. The aim of this paper is to review the techniques most commonly used to measure the thermal conductivity of concrete as well as to consider the factors affecting the thermal conductivity of cement-based materials. In addition, a general equation for predicting the thermal conductivity of concrete is proposed in this study based on data reported by researchers. The results of this review indicate that most researchers have measured the k-value of cement-based materials based on transient methods. The reported k-value in saturated conditions is higher than in dry conditions. Moreover, the measured k-value exhibits a declining trend with increasing temperature. It is concluded that using lightweight concrete in structural and non-structural building envelopes is a valuable method of reducing the amount of heat transfer and energy consumption owing to the lower k-value of lightweight concrete compared to normal weight concrete.

Thermal conductivity of concrete – A review

A review of mechanical properties of fibre reinforced concrete at elevated temperatures

Dispersion of carbon fibers and conductivity of carbon fiber-reinforced cement-based composites

Self-sensing concrete combines electrically conductive filler material and conventional building material together, and is able to realise a sensing function that by measuring the change of electrical properties of the composite under external loading, the stress, deformation and damage could be monitored. It has the advantages of high sensitivity, long service period, excellent compatibility, durability and mechanical strength, and low maintenance cost, and can be potentially applied in structure health monitoring, weight in motion, traffic detection, parking management and many other fields. This paper overviews the details of the composition and role of each component, the fabrication method and the mechanism of the self-sensing concrete. The future prospects are discussed at the end of the paper.

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A state-of-the-art on self-sensing concrete: Materials, fabrication and properties

A review on material design, performance, and practical application of electrically conductive cementitious composites

Mechanical and smart properties of carbon fiber and graphite conductive concrete for internal damage monitoring of structure

Thermal conductivity and mechanical properties of porous concrete materials

Development of cold-mix high-toughness resin and experimental research into its performance in a steel deck pavement

It is quite challenging to use tunnel segment as a repair experiment object due to its large size, the difficulty of installation, and loading inconvenience. To tackle this problem, a 45° symmetrical-bevel RC plate has been employed to substitute segment and conventional RC plate, and to investigate the mechanical behavior of secondary crack problems for concrete segments after repair by polymeric matrix and fiber reinforcement polymers (FRPs). Moreover, elaborate five numerical models of segments were established by means of experiments and 3D finite element method. The prediction results indicated that the mechanical properties of using 45° symmetrical-bevel RC plate were in good agreement with the concrete segments (81.30%). In contrast, those using conventional RC plate showed a larger disagreement (57.49%). Versus and after repair by PM and FRPs, the secondary cracks of concrete segments were improved by 2.86–29.52% of compressive strength compared with the primary cracks. It demonstrated that the experimental results and the simulation results matched well (close to min. 87.89%).

Fei Geng

Papers

Mechanical and smart properties of carbon fiber and graphite conductive concrete for internal damage monitoring of structure

Thermal conductivity and mechanical properties of porous concrete materials

Development of cold-mix high-toughness resin and experimental research into its performance in a steel deck pavement

Secondary Cracks and Mechanical Behavior Prediction of Concrete Segments After FRP Confinement