Abstract

Due to routine maintenance of aircraft on the concrete pavement at army airbases, a large part of the pavement surface is often found saturated with different hydrocarbon-based oil, fuel, and fluid. In addition, the pavement concrete is subjected to the aircraft’s exhaust temperature during operation. This study examined the resistance ability of 3 different cementitious materials: (i) epoxy, (ii) fly ash (FA) based geopolymer with various alkali to fly ash (AL/FA) ratios and (iii) Portland cement (PC) mortar under a simulated airfield circumstance. The mortar specimens were repetitively exposed to a mixture of synthetic engine oil, hydraulic fluids, jet fuel and elevated temperatures (175 °C) for 5 months simultaneously. During the exposures, geopolymer and PC mortar both suffered saponification. The degree of saponification of geopolymer samples is found to be highly reliant on the AL/FA ratios. On the contrary, the epoxy mortar was found to be resistant to saponification. It was also found that the PC mortar developed numerous thermal cracks but epoxy and geopolymer did not experience any visual thermal cracks under the same conditions.

Highlights

  • Received: 7 December 2021Concrete pavements at airfields that house aircraft are often found saturated with hydrocarbon-based synthetic engine lubricant, hydraulic fluid and jet fuel

  • This study examined the durability of geopolymer with various AL/fly ash (FA) ratios, epoxy and Portland cement (PC) mortar while cyclically exposed to a reproduced airfield condition over 5 months

  • Geopolymer and PC mortar both went through the saponification process

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Summary

Introduction

Concrete pavements at airfields that house aircraft are often found saturated with hydrocarbon-based synthetic engine lubricant, hydraulic fluid and jet fuel. This study examined the resistance of geopolymer and epoxy mortar to a reproduced airfield operating condition. This study used epoxy as a single binder to produce a mortar intended to repair degraded concrete at airfields. Some previous experimental studies demonstrated reasons for the rapid surface degradation (scaling) mechanism of ordinary PC concrete at army airbase [2,3,4]. These studies revealed that typical PC is highly attacked by synthetic hydrocarbon oils/fluids at elevated temperatures and causes saponification on the surface of the pavement concrete. The study illuminates the influence of alkali to FA ratios (AL/FA) on the durability of geopolymer under airfield environments

Geopolymer Ingredients and Preparation
Epoxy and PC Mortar Ingredients and Preparation
Durability Test Program
Cyclic Exposures to Elevated Temperature Only
Visual Observations after Exposure to the Replicated Conditions
Residual Compressive Strength of the Exposed Specimens
Mass Loss Due to Cyclic Thermal Exposures
Findings
FTIR Analysis of the Specimens
Conclusions
Full Text
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