Biochar Enriched Concrete for Carbon Sequestration

Abstract

In upcoming years , a lot of construction is going to happen leading to more cement consumption and more GHG’s emissions by default as an embodied carbon. Reduction of cement consumption is possible by partially repacing it with biochar which is a by-product of pyrolysis of biomass or adding it as an additive in cement mortar and concrete for carbon sequestration. Biochar is effective in carbon sequestration activity and results in high water and carbon dioxide holding capacity. Increase in biochar lead to increase in carbon sequestration . As pozzolanic activity lead to strength gaining characteristics and durability of concrete, this study focusses on investigating pozzolanic activity of biochar. Biomass considered in this study were walnut shells and pretreatment was done with 0.1 N HCl and and pozzolanic activity is checked by chapelle test by observing Ca(OH)2 fixation during the titration. It was observed that increase in temperature or Normality of HCl in pretreatment does not enhance pozzolanic activity of biochar . Hence pretreatment with 0.1 N HCl at room temperature for an hour is sufficient to enhance the pozzolanic activity of biochar with much high carbon dioxide sorption as compared to usual concrete without compromising with the strength of concrete. This study reclaims the potential use of biochar in concrete is reliable for carbon sequestration.

Introduction

I. INTRODUCTION

 Building industry’s emissions currently account for 40 percent of total global annual CO2 emissions. Out of which the  third is attributable to embodied carbon. The anticipated growth and urbanization of the global population  will lead to growth of construction of new housings and other infrastructure in upcoming years. India holds second rank in production of cement for the construction work. While 8 % of world’s GHG’s emissions are due to cement production as in the production of cement large amount of  Carbon dioxide is released into the atmosphere known as Embodied carbon. Anything we will do to reduce the amount of cement in your concrete mix will have a significant impact on the overall embodied carbon of the concrete. Hence, Biochar is used as an partial replacement of cement in concrete   to reduce the amount of cement in your concrete mix, also post combustion carbon sequestration is possible resulting in toes towards going net zero emissions where concrete will act as a carbon sink. Previously various literatures were addressed explaining different enrichments in concrete as  a repacement of cement like Metakaolin [1][2] ,Fly ash [3][4], Bottom Ash [5], Rice husk Ash [1], Silica Fume [6][7], Palm oil Fuel Ash [8][9] Bagasse Ash [10] etc. Pyrolysis and Gasification  of biomass are most used method by which the Biochar is formed. Materials like food waste, Poltry waste [11], Agricultural waste  etc. can be considered as Biomass .

In recent times Biochar has been used for enhancing soil properties. Though  The importance of biochar is mainly on Carbon sequestration Activity. This paper Focusses on use of walnut shell Biochar as partial replacement of cement . This study deals with the walnut biochar in cement concrete as a partial replacement of cement  for carbon sequestration .Building material acting as a carbon sink can be a better solution to reduce GHG’s emissions and reduction in Embodied carbon by default. Biochar is a material proved to be having high water  as well as carbon holding capacity which leads to  internal curing action  and Carbon sequestration. Still there will always be a scrutiny regarding the strength of cement mortar or concrete when there will be the talk of replacement of cement. As strength property is known to  be depended on pozzolanic activity of that material which can be enhanced by 0.1 N HCl  Pre-treatment. [11] Increase in normality and Temperature are considered in this study to  check its effect on pozzolanic activity of Biochar.

II. MATERIALS AND METHODS

A. Biochar Production

Walnut shells are generally  utilized for deflashing and cleaning parts,also as low-cost adsorbent materials in an anaerobic filter medium of a De-centralized wastewater treatment system [12] but still there are no much effective ways for  utilization of walnut shells.

In this study Walnut shells are collected from market and converted to biochar by pyrolysis process at a controlled temperature in  the range of 400?C to 450?C.Biochar is then Grounded manually to the size less than 180 microns.

Table shows that  pretreated walnut shell biochar  enrichment in concrete does not compromise with strength of concrete actually it is observed to be increasing strength instead.

Conclusion

The entire study where walnut shell biochar has been used as an replacement in concrete and mortar is reasonable to increase in pozzolanic activity with pretreatment . Also it is liable to carbon sequestration t as increase in pretreated biochar increasing the carbon sequestration without compromising with strength of the concrete. This study concludes that pretreated walnut shell biochar can make building a carbon sink and it is reliable for reduction of cement consumption and to lay hand in pollution combat From cement industry.

References

[1] Gill A S and Siddique R 2018 Durability properties of self-compacting concrete incorporating metakaolin and rice husk ash Constr. Build. Mater. 176 323–32 [2] Coopamootoo K and Masoero E 2018 Cement pastes with UV-irradiated polypropylene: fracture energy and the benefit of adding metakaolin Constr. Build. Mater. 165 303–9 [3] Wang D, Zhou X, Meng Y and Chen Z 2017 Durability of concrete containing fly ash and silica fume against combined freezing-thawing and sulphate attack Constr. Build. Mater. 147 398–406 [4] Bentz D P and Ferraris C F 2010 Rheology and setting of high-volume fly ash mixtures Cem. Concr.Compos. 32 265–70 [5] Minane J R, Becquart F, Abriak N E and Deboffe C 2017 Upgraded mineral sand fraction from MSWI bottom ash: an alternative solution for the substitution of natural aggregates in concrete applications Procedia Eng. 180 1213–20 [6] Wang D, Zhou X, Meng Y and Chen Z 2017 Durability of concrete containing fly ash and silica fume against combined freezing-thawing and sulphate attack Constr. Build. Mater. 147 398–406 [7] Rossen J E, Lothenbach B and Scrivener K L 2015 Composition of C–S–H in pastes with increasing levels of silica fume addition Cem. Concr. Res. 75 14–22 [8] Thomas B S, Kumar S and Arel H S 2017 Sustainable concrete containing palm oil fuel ash as a supplementary cementitious material – a review Renew. Sustain. Energy Rev. 80 550–61 [9] Jumaat M Z, Alengaram U J, Ahmmad R, Bahri S, Islam A B M S 2015 Characteristics of palm oil clinker as replacement for oil palm shell in lightweight concrete subjected to elevated temperature Constr. Build. Mater. 101 942–51 [10] Manu vijay,”Experimental study of concrete strength by replacing baggase ash by marble dust”, May 2015, [11] Zeidabadi Z A, Bhakhtiari S, Abbaslou H and Ghanizadeh A R 2018 Synthesis characterization and evaluation of biochar from agricultural waste biomass for use in building materials Construction and Building Material 181 301–8 [12] Zaheer M., Shaham Ali M.,Huang N. and Aqeel Ashraf M., “Using walnut shells, as a low cost adsorbent material in a anaerobic filter medium of DWATS” Chemosphere elsevier volume 341, November 2023. [13] Nair J.,Shika S., and Sreedharan V., “Biochar amended concrete for carbon sequestration”International conference on Materials , mechanics and structures 2020. [14] Neamah F., Intisar M. and Zainab K., “ Capable of gas sensor MQ-135 to monitor the air quality with Arduino Uno” International journal of Engineering , research and technology, November 2020.

Copyright

Copyright © 2024 Vikram R. Tirpude. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.