Experimental investigation of the effect of pigment and glass fibers on the mechanical properties of Reactive Powder Concrete

The objective of this study was to investigate and compare the effects of using pigment and glass fibers on the mechanical properties of reactive powdered concrete (RPC). The materials used included Portland cement, aggregates, water, pigment, and glass fibers (GF). In the first phase, 33 mix designs were examined, involving various pigment percentages (3 %, 5 %, 7 %) and sand-to-cement ratios, under two curing conditions (40 % and 50% calcium carbonate). The results showed that adding pigment led to reductions in the compressive, flexural and tensile strengths, as well as increased water penetration. These negative impacts worsened as the pigment percentage increased. Therefore, the 3 % pigment mix design was selected as the reference sample for the second phase. In the second phase, 26 mix designs with different GF percentages (8%, 10%, 12%) and sand-to-cement ratios were tested under the same two curing conditions. Subsequently, the compressive strength tests were conducted on different curing days (1, 7, 14, 28, 42, 56, 90 days), as well as the flexural strength, tensile strength, and water penetration tests according to standard procedures on all samples. The findings demonstrated that the compressive strength improved with higher GF content, up to 10 %. However, 12 % GF caused a decrease in the compressive strength compared to 10 % GF. The 10% GF mix exhibited the highest the tensile and flexural strength, and lowest water penetration. In conclusion, it can be said that the mix design with the sand to cement ratio of S1.2C40 is the most suitable mix design from both economic and the compressive strength perspectives. This mix design creates a desirable balance between increased strength and reduced costs, and can be useful for practical applications.