Use of Fly Ash and Rice Husk Ash in Rigid Pavement: A Comprehensive Review
Keywords:
Fly ash, Flexural strength,, Pavement quality concrete, Pozzolanic materials, Rice husk ash,, Rigid pavement, SustainabilityAbstract
Fly ash (FA) and rice husk ash (RHA) serve as sustainable cement replacements in rigid pavement quality concrete (PQC), achieving flexural strengths of 4.5–5.5 MPa while reducing cement by 20–30% and CO₂ emissions by 25–40% through pozzolanic reactions. This review synthesizes 25 experimental studies (2013–2025) showing optimal blends (10–20% FA + 5–10% RHA) yield M40-M50 PQC with 28-day compressive strengths of 45–55 MPa, meeting MoRTH specifications for rural/urban roads. Key findings include 20% FA enhancing flexural strength by 10–15% at w/c = 0.35–0.40, while RHA up to 10% improves durability against sulfate/chloride ingress. Combined replacements minimize cracking and cost by 15–20%, but higher RHA (>15%) reduces early strength. Gaps include long-term fatigue testing under Indian traffic loads and alkali-silica reaction (ASR) mitigation. Future research should target geopolymer PQC and nano-modified FA-RHA blends for 50+ MPa pavements.
