<p>Interest has grown in recycled cement powder waste’s application in building projects as a workable, long-term solution to environmental issues. This work presents experimental results investigating the behaviour of plain and fibre-reinforced waste cement paste with different volume fraction percentages of micro steel fibres (1% and 2%), where densified micro silica partially replaces 10% of the waste cement. For each mix, the superplasticiser and water-cement ratios were maintained constant. The study involved a number of studies, including flow table inspections, Field emission scanning electron microscopy (FE-SEM) tests, scanning electron microscopy with energy dispersive X-ray (SEM–EDX) testing, compressive and flexural strength assessments, dry density measurements, and ultrasonic tests. These evaluations aimed to analyse the specimens’ mechanical and physical characteristics thoroughly. The results showed that substituting densified micro fume and micro steel fibres (SF) for a certain amount of cement could improve waste cement’s properties. Using 2% of the micro-steel fibres significantly affected the cement paste’s compressive and flexural strengths. Nevertheless, an investigation revealed that the inclusion of fibres resulted in a reduction in the amplitude of the sound waves and a decrease in the stagnation flow. The SEM–EDX tests revealed satisfactory adherence between the cement paste and SF. This clarifies why adding SF causes the compressive strength to increase.</p>