Assessing the impact of substituting hypo sludge (paper pulp) in cement and introducing natural fiber in the form of human hair to enhance compressive strength in concrete

Abstract This study investigates the impact of incorporating hypo sludge (paper pulp) and human hair fiber (HHF) into M25 grade concrete to enhance its compressive strength. The research evaluates the effect of 30 % hypo sludge in cement and introducing 2 % HHF, comparing the results with conventional M25 concrete. After 28 days, compressive strength tests revealed that the modified concrete containing 30 % hypo sludge and 2 % HHF achieved a significantly higher average compressive strength of 32.91 N/mm 2 , compared to 26.08 N/mm 2 for conventional concrete. The statistical analysis, including an independent samples t -test, indicated no significant variance ( p = 0.893) between the samples, confirming the reliability of the results. Group statistics showed consistent performance with a standard deviation of 1.67 for the modified concrete. A Bayesian Factor Test, using the Rouder method and assuming unequal variance, revealed a mean difference of 6.8289 N/mm 2 with a pooled standard error of 0.53572, yielding a Bayesian factor of 0.000. This provides strong evidence against the null hypothesis, specifying significant improvement in compressive strength. ANOVA confirmed a statistically significant difference in compressive strength between the groups ( F = 162.489, p = 0.000). This study highlights the potential of these novel materials for eco-friendly construction applications, providing a promising alternative to conventional methods.