Daily Archives: October 30, 2026

Authors: Mr. Prashant Patel, Mr. Pankaj Agrawal

Abstract: Concrete is the most widely used construction material, yet its production consumes large quantities of natural sand, while end-of-life vehicle tyres remain a difficult waste stream. Partial replacement of fine aggregate with crumb rubber from waste tyres addresses both problems, but untreated rubber lowers strength, stiffness and workability and increases water absorption, largely because of a weak bond between the hydrophobic rubber surface and the cement paste. This paper gives a simple review of published work on rubberised concrete, with emphasis on pre-treatment of crumb rubber with sodium hydroxide (NaOH). It covers the properties of waste tyre rubber, the reported effects of rubber on the fresh, mechanical, physical and durability properties of concrete, the nature of the rubber–cement interface, alternative methods of improving that interface, and the mechanisms and parameters of NaOH treatment. The literature agrees on the broad effects of rubber. NaOH treatment is the most widely studied and practical chemical treatment and generally reduces, but does not remove, the strength penalty. Gaps remain in controlled comparison of treated and untreated rubber, reporting of treatment conditions, physical-property data and statistical analysis.

DOI: https://doi.org/10.5281/zenodo.23810899

Published by: vikaspatanker

Authors: Bolarinwa,Sehilat Abike, Adu, Cecilia, Ejiks, Oluwakemi Latifat

Abstract: This study empirically examines how institutional quality moderates the relationship between fiscal policy and fiscal effectiveness in Nigeria from 1996 to 2024. The study employs annual time series data sourced from the Central Bank of Nigeria Statistical Bulletin and World Bank World Governance Indicators. Data were analyzed using Augmented Dickey-Fuller and Phillips-Perron unit root tests, Johansen cointegration, Vector Error Correction Model, Impulse Response Function, Variance Decomposition, Granger Causality, and an interaction regression model. Findings: The results reveal that all variables are integrated of order one I(1) and cointegrated, indicating a long-run relationship. The VECM shows a negative and significant error correction term. The interaction term between fiscal policy and institutional quality is positive and statistically significant, confirming that strong institutional quality amplifies the effect of fiscal policy on economic growth. Impulse response shows that shocks to institutional quality have persistent positive effects on growth. Variance decomposition reveals that institutional quality and fiscal policy jointly explain over 35% of growth variation. Practical Implications: Fiscal reforms in Nigeria will be ineffective without corresponding governance reforms. Policy should focus on strengthening budget credibility, tax administration, and accountability institutions. This study provides direct empirical evidence of governance as a transmission mechanism in Nigeria, moving beyond treating it as a mere control variable.

DOI: https://doi.org/10.5281/zenodo.23805565

Published by: vikaspatanker

Authors: Mr. Prashant Patel, Mr. Pankaj Agrawal Assistant Professor

Abstract: Replacing natural sand with crumb rubber from waste tyres can reduce the demand for river sand and the burden of waste tyres, but untreated rubber weakens concrete because it bonds poorly with cement paste. This paper reports an experimental study of M25 concrete in which 5, 10, 15 and 20% of the fine aggregate by volume was replaced with untreated or sodium hydroxide (NaOH)-treated crumb rubber, compared with a conventional control mix. Workability, fresh density, compressive strength at 7 and 28 days, splitting tensile strength, flexural strength, hardened density and water absorption were measured. All properties deteriorated as rubber content increased. At 20% replacement the 28-day compressive strength fell from 33.4 MPa for the control to 18.9 MPa with untreated rubber and 22.0 MPa with treated rubber. Relative to untreated mixes, treatment raised compressive, splitting tensile and flexural strength by up to 16.4%, 12.9% and 10.8% and reduced water absorption by up to 12.9%, but no rubberised mix matched the control. Two-factor analysis of variance showed significant effects of replacement level and rubber condition (p < 0.001) and no significant interaction. Using a minimum of 25 MPa at 28 days, treatment raised the acceptable replacement level from 10% to 15%. The results suggest that treated rubber concrete is better suited to non-structural and low-to-moderate strength applications.

DOI: https://doi.org/10.5281/zenodo.23804716

Published by: vikaspatanker