Mechanical and thermal properties of lime and hemp concrete (“hempcrete”) manufactured by a projection process

Elfordy, S.; Lucas, Francisco Manuel Demera; Tancret, Franck; Scudeller, Y.; Goudet, L.

doi:10.1016/j.conbuildmat.2007.07.016

Cited by 286 publications

(165 citation statements)

References 14 publications

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“…The density distribution through specimens of sprayed hemp-lime has been assessed previously and found to vary with depth [15]. In addition it has been observed elsewhere that cylinders of hemp lime cast in three layers will tend to fail in compression in the top third [17], suggesting of a lower density of material in this area.…”

Section: Introductionmentioning

confidence: 86%

“…The methods and specimen ages from casting were chosen based on combination of the British Standards for compressive strength testing of concrete and insulation products [24,25], as well as preceding studies on hemp-lime [8,11,15,17]. All specimens were removed from the temperature and humidity controlled curing room and tested at 28 days after casting.…”

Section: Methodsmentioning

confidence: 99%

“…The results are attributed to a reduction of inter particle voids that would reduce the volume fraction of thermally resistive air and increase the volume fraction of structural binder. It is proposed elsewhere [11][12][13][14][15][16] and widely accepted that compressive strength and thermal conductivity of hemp-lime follows an approximate linear relation to density for this reason.…”

Section: Introductionmentioning

confidence: 99%

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The influence of the casting process on the internal structure and physical properties of hemp-lime

2016

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Bio-aggregate composites such as hemplime offer a more sustainable alternative to traditional walling infill material. Hemp-lime, whether in situ or prefabricated, is generally either cast or sprayed, which results in a directionally dependent, typically layered, physical structure. This paper considers the impact of compaction and layering on the directional thermal conductivity, compressive strength and internal structure of the material through use of a novel image analysis method. The results presented indicate that production variables have a significant, and crucially, directionally dependent impact on the thermal and mechanical properties of cast hemp-lime.

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Section: Introductionmentioning

confidence: 86%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The influence of the casting process on the internal structure and physical properties of hemp-lime

2016

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“…Recently, the hotspot interest in the use of rapidly renewable raw materials resources such as vegetable fibers with high tensile strength as a good reinforcing component and/or organic filler into composite materials for automotive [1] and building sector [2,3] is recorded. For utilization of natural materials in buildings, their thermal stability has to be taken into account.…”

Section: Introductionmentioning

confidence: 99%

Thermal degradation of natural and treated hemp hurds under air and nitrogen atmosphere

Števulová

Estokova

Cigasova

et al. 2016

J Therm Anal Calorim

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Sustainability goals are essential driving principles for the development of innovative materials in the construction industry. Natural fibers represent an attractive alternative as reinforcing material due to good mechanical properties and sustainability prerequisites. The study has been focused on the comparative investigation of chemical and physical treatments of hemp hurds and their influence on the thermal behavior of main hemp constituents in air and nitrogen atmosphere. Thermal decomposition of hemp hurds involves several parallel reactions related to heat and mass transfer processes. A comparison of DSC and TG/ DTG results of hemp hurds samples before and after treatments demonstrates a better thermal stability for treated samples. It is caused by changes in chemical composition due to a partial removal of non-cellulosic components from hemp hurds structure, an increase in cellulose content and decrease in its degree of polymerization. The results show different thermal behavior of the hurds samples heated under nitrogen and air atmosphere. Based on DTG records, several-stage process of mass loss has been found for the samples under air, whereas only two-stage process under nitrogen.

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“…Hemp concrete, manufactured by a projection process, as shown by Elfordy et al (2008), has a conductivity that can reach 0.49 W/m K for a volumetric mass of 550 kg/m 3 . By comparison, hemp concrete is an excellent insulating material compared to pozzolan concrete, with a thermal conductivity value varying from 0.206 to 0.616 W/m K.…”

Section: Thermal Conductivitymentioning

confidence: 99%

Effect of Scoria on Various Specific Aspects of Lightweight Concrete

Rajaonarison

Gacoin

Randrianja

et al. 2017

Int J Concr Struct Mater

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Experimental research on the technical characteristics of lightweight concretes incorporating scoria was conducted. The objective of this research is to investigate the feasibility and effectiveness of the use of scoria, in lightweight concretes. Coarse scoria of 5/10 and 10/20 mm were used. A portion of the aggregate mixtures had an average particle size B100 lm. Scorias are often used as the constituents of structural concrete and insulating materials. The usability of the concretes tested in this study broadens as the porosity of the mixtures decreased and the cement dosage increased. According to the cement dosage and frequency types, the absorption coefficients of concretes ranged from 0.14 to 0.47. A compressive strength of 19 MPa corresponded to a density of 1800 kg/m 3 ; compressive strengths from 10 to 18 MPa mapped to densities ranging from 1300 to 1700 kg/ m 3 . The thermal conductivity of mixed concretes without scoria reached a maximum value of 0.268 W/m K. The thermal conductivity values of the concretes mixed without sand were below 0.403 W/m K. As sand content increased, the conductivity evolved from 0.565 to 0.657 W/m K. Freeze-thaw stability tests were conducted for 400 cycles or until specimens deteriorated. The experimental results helped in determining the optimum mixing conditions for the inclusion of scoria in cement to produce lightweight concretes.

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Mechanical and thermal properties of lime and hemp concrete (“hempcrete”) manufactured by a projection process

Cited by 286 publications

References 14 publications

The influence of the casting process on the internal structure and physical properties of hemp-lime

The influence of the casting process on the internal structure and physical properties of hemp-lime

Thermal degradation of natural and treated hemp hurds under air and nitrogen atmosphere

Effect of Scoria on Various Specific Aspects of Lightweight Concrete

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