This paper presents results from experimental and analytical investigations conducted to evaluate the lateral load behavior and capacity of steel-plate composite (SC) wall-to-reinforced concrete (RC) basemat connections. Two SC wall-to-reinforced concrete basemat connection specimens were tested. These SC wall specimens had a height-to-length ratio of 0.6 and did not include boundary elements. The experimental results include the lateral force-displacement (V-Δ) responses of the specimens and observations of local damage such as steel plate local buckling and concrete crushing. 3D finite element models were developed and benchmarked using the experimental results. The benchmarked models were used to conduct analytical parametric studies, expand the database, and gain additional insights into the behavior of SC wall-to-RC basemat connections. The parameters included in analytical investigations were the wall aspect ratio (h/lw), reinforcement ratio (ρ), and wall thickness (T).

The root cause of premature failures in relatively thin (<50 mm) asphalt surfaced roads is often a challenge to solve during forensic investigations in South Africa (SA). This description is based on peer review type discussions with forensic investigations experts as well as published research papers. The areas of ignorance or areas where research effort is needed are identified. These observations serve to identify areas of new knowledge needed in terms of actual verification with measurements, measurement technology, and modeling of the observed phenomena. The main objectives of this discussion paper are to highlight the evolution of distress development in asphalt layers starting from the identification and description of the kind of microcracks, effects of microcracks in the debonding of the asphalt layer from lower layer, and vehicle–pavement interactions (VPI) of moving truck wheels focusing on the thin asphalt layer. Specific reference is made to the need to measure and model the effects of bow waves in front of and next to the loaded rolling wheel.

The construction sector is responsible for a great environmental impact. The cement industry, which is included in this sector, emits about 650 to 800 kg of CO2 per each tonne of cement produced, being one of the most polluting industries in terms of greenhouse gas emissions. The cement manufacturing process releases about 7% of the total worldwide CO2 emissions. However, concrete and cement-based materials present CO2 uptake potential during their service life and post-demolition through carbonation processes. The carbonation reactions rate depends on several factors, namely type and content of cement, porosity of concrete, temperature, relative humidity and exposure conditions area. Therefore, to estimate the CO2 capture of concrete during its life cycle is not a straightforward calculation. Some studies have been developed using different methodologies in order to evaluate the CO2 potential of cementitious elements in service and post-demolition. This paper reviews the documented approaches that quantify the CO2 uptake of concrete over time, summarizing the assumptions adopted for each previous work. Overall, it was concluded that part of the CO2 emissions released during cement production are reabsorbed by concrete products during their life cycle, which partially offsets the environmental impact and reduces the CO2 footprint of the cement industry.

Reclaimed asphalt pavement (RAP) is a recyclable aggregate produced during the demolition of old flexible pavements and consists of natural aggregates (NA) coated with aged bitumen. The detrimental effect caused by the bitumen coating on strength and porosity has limited the use of RAP on traditional cementitious systems. This study investigates the potential use of fine RAP to substitute NA in the production of alkali-activated slag mortars (AAM). The effect of different activator dosages was assessed, i.e., either 4% or 6% Na2O (wt. slag) combined with a modulus of silica equal to 0, 0.5 and 1.0. The characterisation of 100% RAP-AAM consisted of hydration kinetics (Isothermal Calorimetry), pore size distribution (Mercury Intrusion Porosimetry), mechanical performance (Compressive and Flexural strength), and microstructure analysis (Scanning Electron Microscopy and Confocal Laser Scanning Microscopy). The results show that RAP aggregates do not compromise the reaction of the matrices; however, it causes a significant strength loss (compressive strength of RAP-mortars 54% lower than reference NA-mortar at 28 days). The higher porosity at the interface transition zone of RAP-AAM is the main responsible for the lower strength performance. Increasing silicate dosages improves alkaline activation, but it has little impact on the adhesion between aggregate and bitumen. Despite the poorer mechanical performance, 100% RAP-AAM still yields enough strength to promote this recycled material in engineering applications.

Concrete splitting failure due to tension load can occur when fastening systems are located close to an edge or corner of a concrete member, especially in thin members. This failure mode has not been extensively investigated for anchor channels. Given the current trend in the construction industry towards more slender concrete members, this failure mode will become more and more relevant. In addition, significantly different design rules in the United States and Europe indicate the need for harmonization between codes. Therefore, an extensive numerical parametric study was carried out to evaluate the influence of member thickness, edge distance, and anchor spacing on the capacity of anchor channels in uncracked and unreinforced concrete members. One of the main findings was that the characteristic edge distance depends on the member thickness and can be larger than 3hef (hef = embedment depth) for thin members. Based on the numerical and experimental test results, modifications of the design recommendations for the splitting failure mode are proposed. Overall, the authors recommend performing the splitting verification separately from the concrete breakout to design anchor channels in thin members more accurately.

Alkali-activated materials have the potential to replace Portland cement in certain applications. To better understand these binders’ properties, it is relevant to study their rheological behaviour at early ages, like in the case of Portland cement paste. There are already many studies on the rheological behaviour of these materials in the available literature, using fly ash, metakaolin, and ground granulated blast furnace slag as precursors. However, this study discusses the rheological behaviour, mechanical properties, and porosity of ternary alkali-activated binders based on mining mud waste, waste glass, and metakaolin. The precursor consisted of a volume mix of 70% of tungsten mining waste mud, 15% glass waste, and 15% of metakaolin. The activator was a combination of sodium hydroxide and sodium silicate solution. Five activator/precursor (A/P) ratios (0.37, 0.38, 0.39, 0.40, and 0.4) were studied. The result showed that the activator/precursor ratio affects the rheology of paste and their rheological behaviour fit the Bingham model. The relative yield stress (g) and plastic viscosity (h) increased inversely with the A/P ratio, while the workability increased proportionally. Furthermore, some empirical models are proposed to describe the characteristic of yield stress: plastic viscosity and spread diameter versus the A/P ratio and time with a correlation between the rheological parameters and the spread diameter. The increase in A/P ratio has also followed a decrease in compressive strength in all tested samples for all the ages. As expected, an increase of the porosity accompanied the increase of the A/P ratio.

Fastenings are becoming increasingly important in modern building practice. A wide range of products cover for the great flexibility that they provide in a large variety of applications. In order to ensure the safe and economical use of the fastenings, a combined effort of manufacturing firms, practicing engineers and constructors, research organizations, and public authorities has led to the establishment of interrelated design standards, application guidance, and product approvals. It is however evident that failures, in fact even small defects, of fastenings can lead to disproportionate catastrophic events. In addition to these state-of-the-art documents, which reflect the most precise knowledge possible, a management of possible residual risks and hence causes of failure is also indispensable. Due to the great range of fastening systems with different dimensioning and assembly guidelines, load-bearing behaviour and areas of application, and the overall complexity of the subject, a coherent risk management procedure against structural risks can be very helpful in this respect. This article deals with the technical and load-bearing related risks of fastening technology in construction. The objective of the paper is to introduce fundamental concepts and significant risks met in the fastenings design specification and installation. Moreover, it provides a rating of the identified risks and it transfers recommendations for risk mitigation, based on semi-structured interviews with expert professionals who are active in the field. The results are accumulated in a dedicated risk register as a standard tool of the risk management process in civil engineering, which is the first of its kind in current scientific literature. The aim is to assist future practice and research by providing a basis for risk management considerations for fastenings, which moreover reflects actual risks indicated in the outcome of an industry survey.

Fire safety is a critical performance aspect of construction products, and post-installed anchors and rebars are no exemption in that regard. During their service life, anchors and rebars are subjected to different kinds of load actions, so they have to be qualified and designed for critical safety performance. While the qualification guidelines for static and seismic loading have matured to conclusive requirements over the past two decades, the requirements for determining the resistance to fire are just about to consolidate. This contribution strives to provide clarity on the fire rating of post-installed anchors and rebars. For this, the current status of the regulations, as well as the underlying background, is reviewed after a brief introduction. Typical examples of fire ratings in the field of post-installed anchors and rebars are given, and recent research undertaken to close the last regulative gaps is briefly presented.

The aim of this work is to reduce the overexploitation of river sand by proposing a combination of crushed sand and river sand to develop an optimal mix design for concrete. The approach used consisted of a physical, chemical, and mineralogical characterization of aggregates from three quarries located in Yaoundé (Cameroon), followed by the formulation of concrete by substituting 100%, 90%, 80%, 70%, 50%, and 0% of the river sand with crushed sand. A physical and mechanical characterization of the concrete was carried out, as well as a microstructural characterization using SEM/EDS. The results showed that the concrete made of crushed sand only had a higher drying shrinkage at a young age compared to the river sand concrete. Compared to conventional concrete (made using 100% of river sand), the concrete with 50% crushed sand reduces its slump value, has a lower porosity, and has a compressive strength value of 26.3 MPa at 28 days, which is very similar to that of conventional concrete (26.7 MPa). Moreover, it was found that the strength of the concrete increased by 14.4% and 20.6%, respectively, for concrete without crushed sand (BSR0) and concrete with 50% crushed sand (BSR50) by increasing the curing age from 28 to 90 days. The static modulus of elasticity for conventional concrete BSR0 and BSR50 concrete with 50% crushed sand at 90 days was 23.7 and 21.8 GPa, respectively. Thus, combining crushed sand with alluvial sand is a good method to reduce the depletion of alluvial sands in Cameroon.

The valorization and reusing of mining waste has been widely studied in recent years. Research has demonstrated that there is great potential for reusing mining waste for construction applications. This work experimentally investigated the strength development, pore structure, and microstructure of a binary alkali-activated binder. This is based on tungsten mining waste mud (TMWM) and electric-arc-furnace slag (EAF-Slag) using different proportions of TMWM (10, 20, 30, 40, and 50 vt.%). The precursors were activated using sodium silicate (Na2SiO3) and potassium hydroxide (KOH 8M) as alkaline activator solution with solid:liquid weight ratio = 3. Pastes were used to assess the compressive strength of the blended binder and their microstructure. The reaction products were characterized by X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS), and Fourier transform infra-red (FT-IR) spectroscopy, while the porosity and the pores size properties were examined by mercury intrusion porosimetry (MIP). The results show that the partial replacement of TMWM with EAF-Slag exhibited better mechanical properties than the 100TM-AAB. A maximum strength value of 20.1 MPa was obtained in the binary-AAB sample prepared with 50 vt.% TMWM and EAF-Slag. The pastes that contained a higher dosage of EAF-Slag became more compact with lower porosity and finer pore-size distribution. In addition, the results obtained by SEM-EDS confirmed the formation of different types of reaction products in the 100TM-AAB, 100FS-AAB, and the binary-AABs mixtures such as N-A-S-H, C-A-S-H and (N, C)-A-S-H gels frameworks in the system as the major elements detected are Si, Al, Ca, and Na.