Sunflower Stalks versus Corn Cobs as Raw Materials for Sustainable Concrete.

Cătălina Mihaela Grădinaru,Adrian Alexandru Șerbănoiu,Bogdan Vasile Șerbănoiu

doi:10.3390/ma14175078

Cătălina Mihaela Grădinaru, Adrian Alexandru Șerbănoiu + Show 1 more

Open Access

https://doi.org/10.3390/ma14175078

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Journal: Materials	Publication Date: Sep 5, 2021
Citations: 1	License type: CC BY 4.0

Affiliation: Gheorghe Asachi Technical University of Iași

Abstract

Concrete, the most common material in the building industry, involves the use of mineral aggregates that represent an exhaustible resource, despite their large availability. For a series of applications, these mineral aggregates can be replaced by vegetal ones, which represent an easy renewable natural resource. In this study, two types of vegetal raw materials, namely sunflower stalks and corn cobs, were used in developing 10 compositions of ecological microconcrete, with different percentages involved: 20%, 35%, 50%, 65% and 80%; they were analyzed from the perspectives of density, compressive strength, splitting tensile strength, resistance to repeated freeze-thaw cycles, modulus of elasticity and thermal conductivity. The results revealed that the microconcretes with sunflower stalks registered slightly higher densities and better results regarding the compressive strength, splitting tensile strength, modulus of elasticity, and freeze-thaw resistance than those with corn cobs. Lightweight concrete is obtained when more than 50% replacement rates of the mineral aggregates are used.

Highlights

Buildings and construction represent high-demand sectors in terms of energy consumption and CO2 emissions
Replacing 20% of mineral aggregates with aggregates from sunflower stalks reduced the density of the concrete by approx. 8%, while their replacement in rates of 35%, 50%, 65%
This research aimed to provide a comparative analysis between microconcrete compositions with aggregates from sunflower stalks and microconcrete compositions with aggregates from corn cobs

Summary

Introduction

Buildings and construction represent high-demand sectors in terms of energy consumption and CO2 emissions. In order to achieve high energy savings and emission reductions by 2050, the development of low-emission materials for this sector represent a solution to consider, besides net-zero buildings, deep renovations and low-emission energy supply [1]. Concrete represents the most used building material all over the world but it is a nonecological material by definition, if we take into account the amount of exhaustible raw materials used for its production, and the energy consumption involved in obtaining. To produce one ton of Portland cement, around 1.5 tons of raw materials are used (limestone, marl, clay, gypsum) [2]. Cement processing involves high fuel consumption to ensure a kiln temperature of 1450 ◦ C that results in emissions of over 500,000 tons/year of carbon monoxide, nitrogen oxide and sulfur dioxide [2], and around one ton of CO2 for each ton of cement produced [3]

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