The challenges of handling user-hostile alkaline solutions in the conventional alkali-activated binders (AAB) have initiated the development of “just add water” or one-part solid-based AAB systems. This paper aims to present a preliminary investigation on the development of one-part ambient-cured alkali-activated binders produced by synthesising high-calcium fly ash (HCFA) and ground granulated blast furnace slag (GGBS) using sodium metasilicate anhydrous. Three test series were conducted in this study to investigate the effects of GGBS/binder, activator/binder and water/binder ratios on the fresh and hardened properties of the one-part synthesis AAB system. It was found that the SiO₂/Al₂O₃ molar ratio plays an important role in the attainment of compressive strength and limits the amounts of solid activators effective in contributing to the alkali-activation reaction process. The optimum SiO₂/Al₂O₃ molar ratio was found between 3.20 and 3.30. The test results revealed that the optimum proportion between HCFA and GGBS was discovered at a GGBS/binder ratio of 0.50. The optimum activator/binder ratio was between 0.08 and 0.12, and it is recommended that the water/binder ratio should not exceed 0.50. This study demonstrated the potential of the one-part synthesis method in the production of alkali-activated binder for practical structural applications.

Property-based rainwater drainage provision comprises a number of components broadly categorised as roof, surface or underground drainage. These systems are relied upon to prevent water ingress to the building and to avoid localised ponding or flooding. Recognition of the inherently unsteady response of the integrated network, in part driven by a particular rainfall event but also due to the transient nature of the fluid flows therein, is important in allowing an understanding of system performance under both current and future climate conditions. Codes and standards suggest that roof drainage systems, conventional or siphonic, are designed using a single rainfall intensity figure, representative of the most intense part of a longer storm, whereas runoff to surface and underground drainage is typically based on a single-peaked rainfall profile. Together with the difference in event duration typically adopted as part of the design process, this means that, unless a straightforward uplift factor is applied, then understanding the potential impacts of climate change on overall system performance can be difficult. Using numerical modelling techniques to analyse the performance of a case study site located in Edinburgh, this research identifies an appropriate common rainfall event from which a system-specific exceedance threshold is identified. Specification of this rainfall intensity facilitates an exploration of the impacts of climate change undertaken within the context of UKCP09 projections. Using gutter overtopping as an indicator of failure, this paper explores possible changes in the frequency of system under-capacity under varying future climate change scenarios. Practical application: Engineers are encouraged, in relevant codes and standards, to take account of the potential impacts of climate change when designing rainwater drainage systems for buildings. However, little guidance is offered therein on how to achieve this. This paper presents an example of UKCP09 climate change projections, specifically Weather Generator precipitation data, applied to a case study site that integrates roof, surface and underground drainage networks. Results illustrate the possible change in frequency of system failure, identified in this case as gutter overtopping.

The development of technology has made it easier for engineers to design and test models that allow simulation of real-time water distribution networks with greater accuracy. However, with so many nodes and links in a network, building a model still requires some simplification. One such simplification is the ‘conservative approach’, which applies the principle of ‘lumped demand’, taking the demand only from nodes at the ends of pipes. Herein, the full effect of lumped demand on key water parameters is analysed, on a large-scale network based on as-built networks of Al Furjan and Dubai Silicon Oasis, Dubai, UAE for different conditions. Epanet and WDNetXL software are used for the analysis, and results show the impact of different levels of skeletonisation on the head and velocity values for the two models. The analysis indicates that the head changes are high for a branched network under the extreme condition of firefighting. It includes the effect of skeletonising local tanks, with changes being higher when all tanks are empty. These findings provide a critical evaluation of the performance of this method for the Middle East region and it is concluded that the considerable velocity changes observed in the models could lead to overdesign.

This paper presents the findings of an 18-month study of detritus accumulation at two siphonic rainwater drainage systems installed in a building in Edinburgh. Findings are based on an analysis of data recorded from the site, and are positioned within the context of enhancing representation of the outlet loss coefficient used within both steady-state design calculations and finite-difference-based unsteady flow modelling techniques. The scope of findings reported herein is extensive but, in the main, shows how detritus accumulation not only builds relatively rapidly but also that ‘wash-through’ or ‘displacement’ occurs. Further, data suggest that detritus accumulation in the gutter, that is either wind-blown or is introduced from roof runoff, can, and does, build around the outlet with only relatively low intensity rainfall but that high-intensity rainfall events do seem to result in a direct and significant increase in blockage. An indication of the impact upon performance, assessed using simulation software, is also presented. Practical application: This paper reports patterns of detritus accumulation at on-site siphonic rainwater outlets. Changes in detritus ‘categories’ are mapped to corresponding weather data and conclusions drawn on influencing factors. The paper therefore yields key information for building owners/operators on the extent of detritus accumulation at siphonic system outlets. Outcomes also inform designers of the potential shift in loss coefficient and flow performance post-installation.

Simultaneous peak water flow (SPWF) is calculated during building design and construction to inform the design flow, which dictates the sizing of the water supply system. SPWF represents the maximum instantaneous water flow rate and has been evaluated at the 99th percentile since the first development of estimation models in 1940. This percentile represents the satisfactory performance at which water is delivered to the building occupants - in this case, 99% of the time the water is supplied with sufficient volume and pressure, while adhering to health and safety regulations, despite any number of simultaneous uses. However, this value has not been justified nor re-evaluated and was taken as the standard value in succeeding model developments. To address this gap, this study examines different percentile levels of satisfactory performance in building water supply to evaluate the current 99th percentile and assess the most efficient level for the given case study buildings. A monotonic neural network was employed in a water fixture use probability optimization framework to model the SPWF at different quantiles. Incorporating monotonicity into the network enhances the model’s interpretability and the robustness of the results, enabling flexible evaluation across different levels. It was shown that the peak water demand of the multi-residential case study buildings can be met at a 98th percentile SPWF. The findings suggest that designing for the 98th-percentile SPWF level provides adequate capacity to satisfy the peak water demand of the multi-residential case-study buildings. Choosing the 98th percentile resulted in a reduction of up to 17.36 L/s, which is around 87.26% reduction compared to design flows from building codes.