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Sustainable building should at least be affordable and carbon neutral. Sub-Saharan Africa (SSA) is a region struggling with housing affordability. Residential buildings are often constructed using block-based materials. These are increasingly produced using ordinary Portland cement (PC), which has a high carbon footprint. Using alternative Supplementary Cementitious Materials (SCMs) for block production might reduce the footprint and price. The purpose is to assess the level of information for SCM use in blocks in SSA and to use this information for Diagnosing the improvement potential as part of an Opportunity Study. Results from the scoping review show that aggregated information on SCMs and the quantities available is limited. Diagnosing the theoretical improvement potential in using cassava peel ash, rice husk ash, corn cob ash, volcanic ash and calcined clays, indicates that SCMs could represent a yearly value of approximately USD 400 million, which could be transferred from buying cement to local production. The use of SCMs could save 1.7 million tonnes of CO2 per year and create some 50,000 jobs. About 5% of the PC used for block production could be substituted, indicating that, in addition to using SCMs, other solutions are needed to secure production of sustainable blocks.

The introduction of autonomous and stimulated autogenous self - healing of concrete cracks has been a wonderful technological breakthrough for our built infrastructure. By reducing manual dependence on repair and maintenance activities on concrete public structures, the application of self-healing can potentially save millions in public economy. However, despite the existence of a large body of research on the domain, the judgement to choose one out of several potential strategies to effectively heal a crack is still met with heavy contestation. Currently, the approach to biologically heal a crack by promoting bacterial precipitation of Calcium Carbonate crystals, is deemed the most environment friendly of all. Research on this has proved that this approach is indeed successful in closing cracks up to at least 0.4mm. However, the bacteria responsible for the precipitation is dependent on the constituent precursor and the nutrients of the healing agent. The bacterial precursor that has been successfully applied so far in OPC cementitious composites is often based on lactic acid derivatives, that involve substantial costs in its production process. Recent studies have also demonstrated some incompatibility of the same precursor on low pH environments, such as that characterised by the addition of supplementary cementitious materials like blast furnace slag. For instance, a higher dosage of the lactic acid based precursors lead to negative effects in strength in blast furnace slag cements. In the Netherlands, CEMIII/B (slag cements) finds reason- ably larger market share than OPC cements. As such, the incompatibility of lactic acid based bacterial self-healing agents presents a discouraging scenario. Polyhydroxyalkanoates or PHA extracted from waste streams, have been suggested to be a low cost biodegradable polymer that can effectively replace high cost polymers such as PLA (poly lactic acid). It is also established in recent literature, that PHAs can be met

In this work, an investigation was carried out to assess the use of pH sensitive encapsulation for carbonation triggered release of Sodium Monofluorophosphate (NaMFP) - an inorganic healing agent. To do so, a state-of-the-art review of pH sensitive wall material and a technique to fabricate the same, to encapsulate NaMFP, was performed. The outcome of comparative analyses conducted on prospective shell materials and encapsulating techniques yielded three potential shell materials and two possible techniques. These findings can aid in future experimental investigations to scale up the use of such encapsulation technologies in the construction sector. This would contribute to the research in producing smart cementitious materials that can detect minute changes in their environment and performtargeted healing, without the need for human intervention.