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GREENING THE LOCAL CONSTRUCTION MATERIALS BY INTEGRATING AGRO-WASTE FIBRES INTO CONCRETE

Authors: Y Raghoo, H Ramasawmy, M Gooroochurn, J Chummun, A Seeboo, N Brown

Presenter: Ms Y Raghoo

MPhil/PhD

University of Mauritius

University of Mauritius Research Week 2021

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Outline of Presentation

The Local Construction Industry
The Raw Materials used in Concrete Making
Concrete Masonry Unit
Natural Fibre Use
Aim of Research Study
Mechanical strength
Thermal Insulation
Current Experimental Modalities
Conclusion

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The Local Construction Industry

(Source: Saker., 2019)

(Source: l’express.mu., 2021)

(Source: NHDC., 2021)

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The Raw Materials used in Concrete Making

Mainly from mineral reserves; involving exhaustive extraction and much transportation

(a) Mineral resources extraction

(b) Transportation of materials

(d) Transportation of materials to concrete processing plant

(e)Concrete Masonry Units

Figure: The process of concrete block making

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Concrete Masonry Unit

Generic term – concrete blocks;
Mainly used for residential and commercial building envelopes and partitioning walls;
Owing to the resource-depleting and polluting nature of the concrete making process, a shift in the use of traditional construction materials to sustainable ones is urged;
SDG 11 – Sustainable Cities and Communities empowered.

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Natural Fibre Use

Extraction from locally available agro-wastes;
A series of beneficial traits:

Figure: Advantages for the use of Natural Fibres

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Aim of Research Study

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The Integration of Natural Fibres in Concrete Masonry Units and investigate the potential improvements on the overall mechanical strength and thermal performance of these units

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Mechanical Strength

Promising results from literature for use of natural fibres in concrete masonry units;
Amongst the various fibres reviewed, sugarcane bagasse and banana fibres are considered;
Sugarcane Bagasse fibre: Increase in compressive strength of the blocks by 3% at volume fraction of 1%;
Banana fibre: Rise in compressive strength of the blocks by 6.7% at volume fraction of 2.5%.

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Thermal Insulation

Fluctuating weather patterns in Mauritius with peak temperature in summer at 36°C;
120 000 units of AC were installed in 2011 for 255 230 concrete buildings;
Presently, 365 000 households contributing to additional energy needs for installation of HVAC systems;
Low thermal conductivity – intrinsic property of natural fibre;
Investigations needed to characterize thermal conductivity of building fabric with natural fibres.

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Current Experimental Modalities

Banana fibres chosen –

-Ease of extraction of fibres from agro-waste;

-locally availability;

-desired technical properties;

Experimental procedures led to the following findings:

�Fibre Length	0.5 m to 1.5 m
Fibre Yield	1.0% to 1.8%
Tensile Strength

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Current Experimental Modalities (cont.)

Undesired fibre properties: surface impurities impacting on strength and hydrophilic nature impacting on durability;
NaOH alkaline treatment – commonly used fibre treatment approach – non-sustainable method: by-products from the treatment;
Environmental-friendly treatment currently under investigation;
New approach: Increase of 45% in treated fibre tensile strength;
Better compressive strength and thermal performance of the banana fibre concrete masonry unit expected.

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Conclusion

New infrastructural projects in Mauritius under the construction sector;
Concrete – an important material in this industry;
Unsustainable nature of concrete blocks regarding materials’ sourcing and manufacturing calls for a better ecological approach;
Use of Natural fibres in concrete blocks;
Literature findings for improved compressive strength of natural fibres in concrete blocks;
Natural fibre possess low thermal conductivity for enhancing the fabric’s insulation potential;
Investigations conducted for banana fibre yield and tensile strength;
A novel eco-friendly fibre treatment approach to replace the conventional sodium hydroxide treatment in progress with promising tensile strength results;
Natural fibre combined with an environmental-friendly treatment promises a more sustainable construction pattern for our local industry.