## 5 Conclusions  
The aim of this study is to explore a proper way to (re)utilise BJPA (produced by families and temples during religious activities) in cement-based materials, making prompt responses to the current trend in zero carbon emission. Thus, this study identifies the unforeseen consequences on CS of substituting cement with various BJPA proportions and curing the mortar at different temperatures, according to the different W/B ratios applied. This may help construction companies and construction sites reduce their carbon emissions and achieve their Sustainable Development Goals (SDGs). The reasons for doing so are buried in the goals for environmental protection and the optimal recycling use of waste materials. * Using BJPA in the concrete material is carbon-free, because the carbon had been emitted previously when the joss papers were combusted for their main religious praying purpose, and the action to mix BJPA does not lead to any more carbon emission. * Replacing cement with any material (at best it is carbon-free like BJPA) can also reduce the use of cement and, thus, the carbon emission to produce cement, since the production processes of the cement material lead to 7% of total carbon emissions on the globe. * BJPA is, in itself, a waste, and the disposal of BJPA has long been troublesome. Replacing cement with BJPA is a meaningful treatment for BJPA wastes. From the main results of our experiment, it is recommended that by imposing a higher curing temperature, the full-aged (#days = 120) sample that is cured at T = 50 \({}^{\circ}\)C or 75 \({}^{\circ}\)C with 5% of cement being replaced with BJPA renders the 'best practice', whereas the samples were ranked based on their CS values (in MPa). The top three samples, all of which were found with a W/B ratio of 0.4 and could be justified as having 'indifferent performance', were selected, but only the two admixtures with BJPA were kept (as abovementioned). Since most of the watched mechanical properties of a concrete sample are strongly correlated to its CS, such a result has corrected the previous monotonous thought that 'one must sacrifice CS if any BJPA is added'. Rather, a true statement should be: 'the admixture portfolio of cement mortar with 5% BJPA added can possess even higher CS, subject to some higher temperature imposed during curing'. Despite this, there are just a few references in the literature about replacing cement with BJPA, this theory-amending knowledge is definitely the most significant concluding remark of this study. Furthermore, the data analysis revealed interesting insights. A logarithmic relationship was observed between #days (of curing) and the CS of the samples. The correlations between CS and each experimental factor (the W/B ratio, SR-BJPA, T, and #days) revealed that only the correlation between T and CS was barely weakly positive, whereas the correlation between each other variable (the W/B ratio, SR-BJPA, or days) and CS was at least weak (weak negative for the W/B ratio and CS). Univariate SLR modelling identified the effect of each experimental factor on CS. The four models were significant, but the explanatory power of the model using the W/B ratio as the independent variable was low, whereas that of the model using T as the independent variable was nil. Subsequently, bivariate MLR modelling identified the effect of each pair of variables on CS. The six models were significant, but those that used T as one of the two predictor variables had lower explanatory power. By contrast, models using SR-BJPA as a predictor variable showed qualified explanatory power. However, only the model using the combination of T and W/B ratio is unacceptable, connoting that five of the six models can be used in practise to predict the CS. Anyhow, the factors that can be used as predictors in the future have been identified, and the ten SLR/MLR models may form a 'knowledge bank' for predicting the CS of a concrete material with BJPA being added before it is made. This study can be expanded in the future.