Abstract

India is one of the prominent producers of coconuts in the world. Along with the desired products, many undesirable by-products are also generated from the coconut and coir industry. Among the various by-products, coir pith and short coir fibres are the major ones and are obtained during the extraction of long coconut fibres. Raw coir pith was heated in a metallic vessel at 450 ℃ to obtain coir pith ash. In this study, the impact of the presence of CPA as a supplementary cementitious material, on the various mechanical and durability parameters are taken into consideration. The various parameters considered for assessing the mechanical performance include compressive strength, split tensile strength, flexural strength and Ultrasonic pulse velocity. Water absorption and resistance to sulphuric acid environments were considered to evaluate the durability of CPA blended concrete. The resistance of CPA blended concrete against sulphuric acid environment was evaluated by considering the variation in weight, water absorption and percentage loss in compressive strength. Five concrete mixes were used for the study with CPA content ranging from 0% to 20%. Indian standard method of concrete mix design with water-cement ratio 0.45 was adopted. To understand the effect of change in water-cement ratio on the durability parameters of concrete, the study also considered other water-cement ratios like 0.40 and 0.50. Results indicated that the mechanical and durability performance improves when CPA is used as supplementary cementitious material. Also, the specimens with water-cement ratio 0.40 performed better than other ratios.

Highlights

  • The utilization of by-products from industrial and agricultural sectors as supplementary cementitious materials (SCMs) are gaining popularity among numerous researchers across the globe

  • Though the durability of concrete can be assessed by compressive strength to some extent, it may not be entirely true that a strong concrete specimen or member is always durable since damage can occur due the harsh environmental conditions [8]

  • The coir pith ash (CPA) used for the study was prepared by heating coir pith at 400oC for 4 hours

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Summary

Introduction

The utilization of by-products from industrial and agricultural sectors as supplementary cementitious materials (SCMs) are gaining popularity among numerous researchers across the globe. The external factors include chemical attack and mechanical destruction induced by erosion, abrasion, impact and cavitation. Concrete is alkaline in nature and the acidic environment tends to impart neutralization reaction which reduces the alkalinity of concrete by reacting with hydration products to form calcium sulpho-aluminate (ettringite) and gypsum. These products possess low structural strength but require more space than the reagent compounds. The research aims to assess the performance of binary blended cement concrete containing CPA passing through 90 microns by considering mechanical and durability parameters. The coir pith ash (CPA) used for the study was prepared by heating coir pith at 400oC for 4 hours. The details of various chemical components of CPA are shown in table 1

Materials
Ultra Sonic Pulse Velocity Test
Compressive Strength Test
Flexural Strength Test
Water Absorption Test
Resistance Against Water Absorption
Variation in weight of Acid Attacked Specimens
Variation in Compressive strength
Compressive Strength of CPA Blended Concrete
Microstructural Analysis of CPA Blended Concrete by SEM
Split Tensile Strength of CPA Blended Concrete
Flexural Strength of CPA Blended Concrete
Water Absorption of CPA Blended Concrete
Ultra Sonic Pulse Velocity Test on CPA Blended Concrete
Resistance of CPA Concrete Against Acid Environments
Conclusion
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