The Institution of Civil Engineers’ Construction Materials journal will continue to publish six issues every year whilst diversifying its content to include a wider range of traditional and non-traditional construction materials (e.g. bio-based building materials, ultra-high-performance concrete (UHPC), additive manufacturing (three-dimensional (3D) printing), engineered cementitious composites (ECCs), geopolymer concrete, earthen ramped, timber, waste recycled materials, construction materials and technologies for sustainability and energy efficiency, etc.). The journal continues internationally to disseminate and publish the lasted research on construction materials for academia, industry, stakeholders and other audiences.
This edition of Construction Materials covers a wide range of research including hybrid fibre-reinforced engineered cementitious composites, the use of shredded waste tyre rubber to reinforce soils and drive-in torque for self-tapping screws into timber.
The first paper, by Ali and Nehdi (2022), explores behaviour of hybrid fibre-reinforced ECCs with strain recovery. The paper summarises the tensile and flexural properties of a novel ECC that incorporates a hybrid combination of short and dispersed polyvinyl alcohol and shape memory alloy (SMA) fibres. This work has demonstrated the strain recovery capability of the composite by using heat treatment, which led to the closing of cracks thanks to the shape memory effect of the SMA fibres. The paper presents an inverse method which was successfully validated to predict the tensile properties of different ECC mixtures based on results of the simple four-point bending test as an efficient alternative to the uniaxial tensile test to determine the tensile behaviour of fibre-reinforced cementitious materials (FRCC). The investigation has demonstrated that using the proposed method provided savings in the time and cost required to use complicated uniaxial tensile testing, while achieving adequate precision.
The second paper, by Soltani et al. (2022) from the University of Adelaide, reports a study of the use of shredded waste tyre rubber to reinforce expansive soils. Fine and coarse rubber particles with four different contents by weight were used to reinforce soil. Experimental investigation was conducted on the rubber-reinforced soils which were subjected to unconfined compression, split tensile, direct shear and desiccation-induced crack tests. The results demonstrated improvements in cracking intensity and shear strength with higher rubber contents. However, rubber contents greater than 10% raised failure concerns during compression and/or tension, attributed to clustering of rubber particles under non-confinement test conditions. It was observed that the coarse rubber aggregates helped to increase ductility, lower stiffness and raise energy adsorption capacity rather than producing peak strength improvements. It was reported that 10% of rubber resulted in a notable decrease in the swell–shrink capacity as well as improved optimised strength-related properties.
The third paper reports the relationships between drive-in torque, thread configuration, screw diameter and pre-drilled holes (Zhang et al., 2022). In this study, two types of screws involving three different thread configurations were applied and the required drive-in torque of the screws, in conditions with and without pre-drilled holes, was also compared. The experiment results demonstrated that the drive-in torque for partially threaded screws was significantly lower than that of fully threaded ones. The results showed that knots can significantly influence the positioning of the screw and increase the drive-in torque. Additionally, the application of a pre-drilled hole exhibited an effective way to minimise the influence of knots. The study indicated that with an appropriate consideration of thread configuration, partially threaded self-tapping screws can not only achieve the same efficiency as fully threaded ones, they will also benefit from reduced drive-in torque force. Finally, it was found that adequate reduction of the drive-in torque of self-tapping screws not only decreases the risks of damaging the screw but also leads to faster installation and reduced costs in the timber construction industry.
