Table 1. Mix proportions and physical characteristics of materials used.

Component	Quantity (g)	Notes/specifications
Ordinary Portland cement	314	OPC 42.5 grade
Standard sand	822	ASTM C778; particle size: 0.15–2 mm
Water	115	Tap water
Ethanol	115	Analytical grade
Spirulina@DFNS	Variable (0–4%)	As % replacement of cementitious material (by weight)