Effect of Elevated Temperature on Compressive Strength and Physical Properties of Neem Seed Husk Ash Concrete.

Kizito Patrick Mwilongo,Yusufu Abeid Chande Jande,Revocatus Lazaro Machunda

doi:10.3390/ma13051198

Abstract

High temperature rise mostly caused by a fire outbreak is currently becoming a threat that endangers concrete’s structural performance for buildings and the safety of occupants. The behavior of concrete after fire subjection has been of much interest for the structural materials design purposes. This study investigated the physical properties and the compressive strength of M25 concrete incorporating Neem Seed Husk Ash (NSHA), exposed to and through targeted different levels of temperature (200 °C to 800 °C) for a period of three hours in an electric furnace. The NSHA was produced by calcining neem seed husks at 800 °C for six hours and then sieved through the 125 μm sieve. Different amounts of NSHA were investigated while considering the plain concrete as the control sample. 150 concrete cubes of 150 mm sizes were cast and properly cured for 7 and 28 days. The experimental results show that the compressive strength of the 5% NSHA concrete exposed to temperatures up to 400 °C is 21.3% and 23.8% better than the normal concrete at 7 and 28 curing days, respectively. Surface cracks and spalling are noticeable at 600 °C and 800 °C for all samples considered in this study.

Highlights

Concrete is a composite building material comprised of coarse and fine aggregates glued together with cement paste that results in the desired structure upon hardening
The Neem Seed Husk Ash (NSHA) used in this investigation was considered as pozzolanic material suitable for concrete, and can be classified as fly ash Class F, since the sum of silica, alumina and iron oxide exceeds 70% [33]
The present study examined the residual compressive strength and spalling effect of the cement-NSHA blended normal concrete subjected to elevated temperatures

Summary

Introduction

Concrete is a composite building material comprised of coarse and fine aggregates glued together with cement paste that results in the desired structure upon hardening. It is a material of choice for applications that require high-temperature-resistant materials. The current development of infrastructures due to urbanization has led to about 11 billion tons of concrete being consumed annually, and is likely to exceed 18 billion tons by the year 2050 [2]. This implies that its raw materials, more cement, are highly consumed. It is reported that in every ton of ordinary Portland cement (OPC) manufactured, approximately 900 kg of CO2 is produced, contributing to about 7% of the entire CO2 emissions worldwide [3]

Methods

Results

Conclusion