Mechanical, Thermal and Fire Behaviour of Hemp-Based Composites with Different Binders for Sustainable Building Applications

Anilcan Aygun; Fahri Birinci; Selim Aytac; Ali Kemal Ayan; Hasan Alp Sahin; and Ibrahim Isildak

doi:10.29187/2458-973X.1216

Article Open Access1 January 2026

Mechanical, Thermal and Fire Behaviour of Hemp-Based Composites with Different Binders for Sustainable Building Applications

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Anilcan Aygun¹, Fahri Birinci², Selim Aytac ³, Ali Kemal Ayan ⁴, Hasan Alp Sahin ³, and Ibrahim Isildak ⁵

¹Eindhoven University of Technology, Department of the Built Environment, Eindhoven 5612 AE, the Netherlands

²Ondokuz Mayis University, Department of Engineering Faculty, Samsun 55270, Türkiye

³Ondokuz Mayis University, Institute of Hemp Research, Samsun 55270, Türkiye

⁴Ondokuz Mayis University, Department of Agriculture Faculty, Samsun 55270, Türkiye

⁵Yildiz Technical University, Department of Bioengineering, Istanbul 34349, Türkiye

Journal of Sustainable Construction Materials and Technologies 2026, Vol. 11, Issue 1, pp. 9; doi.org/10.29187/2458-973X.1216

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Abstract

This study investigates the physical, mechanical and thermal properties of hemp-based composites produced with traditional binders such as lime, cement, gypsum, clay, and water-based glue. Hemp fractions of different sizes (splinter, shiv, fiber and powder) were combined with these binders to manufacture cube and plate specimens, which were tested for physical, mechanical, thermal, and temperature resistance properties. The study aims to compare the mechanical, physical, thermal, and fire behaviour of these composites to assess their suitability for sustainable construction applications. The hemp-based composites were tested for unit weight, water absorption, compressive strength and thermal conductivity. Most specimens are lightweight (<1000 kg>/m3), and exhibit good thermal insulation performance and high compressive deformability, making them suitable for seismic-prone regions. The glue-based composite had the lowest unit weight, measured as 330 kg/m3. Thermal conductivity ranged from 0.051 to 0.243 W/m· K, with several mixtures performing better than natural pumice. While cement-based composites showed the highest compressive strength, ranging from 5.5 to 24.8 kg/cm2, natural hydraulic lime is the lowest. Water absorption was high, and moisture release occurred slowly across all hemp fractions. Combustion tests indicated that hemp-based materials have moderate temperature resistance, with charring temperatures ranging from 238–265°C for raw hemp and 300–385°C when mixed with binders. Overall, hemp-based composites are lightweight, eco-friendly, and suitable for non-load-bearing construction and insulation applications. However, improvements in moisture resistance and long-term durability are necessary to enhance their practical applicability.

Keywords: Binder; Building materials; Fire resistance; Hemp; Sustainability; Thermal conductivity

1. Introduction

Building materials are of vital importance in the construction industry and there is a growing trend to focus on sustainability and environmental friendliness. Hemp, known for its diversity, renewability and carbon-negative characteristics, has emerged as a potential alternative for producing environmen-

tally friendly building materials. Recent research has examined the physical and mechanical properties of hemp composites formed with diﬀerent binders, highlighting the potential of industrial hemp as a natural ﬁber source for construction purposes [1]. Additionally, studies on surface treatment of hemp ﬁbers to improve ﬁber/matrix interfacial bonding have contributed signiﬁcantly to

Received 10 February 2026; revised 10 March 2026; accepted 16 March 2026. Available online 21 March 2026 * Corresponding author. E-mail address: a.aygun@tue.nl (A. Aygun). https://doi.org/10.29187/2458-973X.1216 2458-973X/© 2026 Published by Yıldız Technical University Press, İstanbul, Türkiye. This is an open access article under the CC BY-NC 4.0 Licence (https://creativecommons.org/licenses/by-nc/4.0/).

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the mechanical performance of hemp composites [2]. Hempcrete, a hemp-lime mixture, is a well-known hemp-based material due to its favorable properties and low carbon proﬁle. Hempcrete houses have been built in many countries, and research on this topic has increased substantially [3]. Combining hemp shivs with lime-based binders provides eﬀective thermal and acoustic insulation, enabling construction without additional insulation layers [4–6]. Beyond lime, alternative binders such as gypsum, geopolymers and starch have also been explored to produce ecological building materials with low density and promising thermal conductivity [7]. Hemp materials can be manufactured in various forms and used in both construction and insulation applications [8]. Their total carbon emission balance is negative, and previous research shows that using organic materials in cement production reduces CO2 emissions [9]. Hempcrete walls also demonstrate a high CO2 absorption capacity [10], and bio-based insulation materials combining ﬂax and hemp oﬀer competitive thermal performance [11]. Furthermore, hemp blocks exhibit favorable thermal behaviour and ﬁre resistance, with ﬂaming combustion temperatures reaching up to 700 °C [12]. Previous work has investigated a wide variety of hemp-based composite conﬁgurations. Studies include polyethylene ﬁlm-coated hemp composites, evaluating water absorption, mechanical strength, and dynamic behaviour [13]; hemp ﬁber– polyurethane composites to determine critical ﬁber length [14]; and composites incorporating hemp ﬁber powder, which improves compressive strength [15, 16]. Layered hemp-based composites have also been shown to provide high-quality acoustic insulation. Hempcrete mixtures generally show a dry unit weight of 200–800 kg/m3 and thermal conductivity coeﬃcient between 0.06-0.12 W/m·K [17]. Additionally, the heat capacity of hemp-reinforced composites has been reported to be around 1500 J/kg·K [18]. Other studies have focused on the mechanical properties of hemp-reinforced polypropylene [19], physical properties of hemp shiv and ﬁber [20], and the suitability of hemp materials for installation insulation [21]. Research shows that using only cement as a binder in hempcrete can lead to design limitations, resulting in inferior performance compared to alternative natural binders such as clay and lime, and does not improve material strength. Hempcrete is nearly seven times lighter than traditional concrete [5], making it an attractive lightweight material for construction. With the increasing use of hemp in the construction sector, it has become important to determine its mechanical, thermal, and physical prop-

erties, particularly for non-load-bearing applications [22–24]. Studies have also examined the integration of hemp shivs with various binders in frame structures for both structural and insulation purposes [25]. This study aims to evaluate and compare the physical, mechanical, thermal, and ﬁre behaviour of hemp-based composites produced with diﬀerent traditional binders, in order to assess their suitability for sustainable building applications.

2. Material and methods

Industrial hemp was obtained from the Institute of Hemp at Ondokuz Mayis University. Five diﬀerent hemp fractions were used: coarse splinter (T1), medium shiv (T2), ﬁne shiv (T3), powder (T4), and ﬁber (T5). T1 represents the woody shredded hemp shiv with an average length of 15 mm, a width of 2 mm, and a thickness of 1.5 mm. T2 and T3 dimensions were obtained by reducing the dimensions of T1 length, while T4 consisted of particles smaller than 1 mm. Traditional binders used in the study included cement (CEM I 42.5), lime putty, natural hydraulic lime (NHL 3.5), plaster, clay, and polyvinyl acetate (PVAc) water-based glue, all used without chemical modiﬁcation. The proportions of hemp and binders were determined based on practical workability and traditional mixture ratios. Total hemp content ranged from 14% to 30% by weight in the mixtures. The quantities of materials used are presented in Tables 1 and 2.

2.1. Specimen preparation

The specimens for partition elements were produced as 15 cm cubes, while 20 × 30 cm and 30 × 30 cm plates with a thickness of 3 cm were prepared for cladding and insulation tests. For ﬁre-temperature resistance tests, 10 cm cube specimens were manufactured. All mixtures in Table 1 were prepared using a dynamic mixer and placed manually into molds. Plate-type specimens were compacted using a standard testing machine (capacity: 2000 kN) by applying pressures of 15 kg/cm2 (20 × 30 cm plates) and 20 kg/cm2 (30 × 30 cm plates). The specimens containing cement binder were removed from the molds after one day. They were cured by watering three times a day. All other specimens were demolded after three days. Minimum curing was applied to lime and gypsum mixtures (watering once per day). Specimens with water-based glue were air-dried without any additional curing. Clay-based specimens were kept in a closed environment for 1–2 days after demolding,

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Table 1. Quantities and proportions of hemp products and binders. Components

Coarse splinter (g) Coarse shiv (g) Medium shiv (g) Fine shiv (g) Powder (g) Fiber (g) Hemp (g) Binder (g) Water (g)

*The labels in the ingredients section are respectively (Cem-Cement, NHL-Natural Hydraulic Lime, GL-Polyvinyl Acetate Glue (PVAc glue), PL-Plaster, L-Lime), those ending with P1 indicate 30 × 30 × 3 cm plates, and those ending with K indicate 15 × 15 × 15 cm cubic blocks. Table 2. Summary of specimen groups, dimensions, binders, and relevant standards. Specimen Type

15 × 15 × 15 cm Cement, Lime Putty, NHL, Clay, Plaster, PVAc Glue Plate specimen 30 × 30 × 3 cm Cement, Lime Putty, Clay, Plaster, PVAc Glue Plate specimen 20 × 30 × 3 cm Cement, Lime Putty, Clay, Plaster, PVAc Glue Fire test specimen 10 × 10 × 10 cm Clay, Lime Putty, Plaster

Compressive strength, EN 12390-1 (standard deformation testing machine, 2000 kN) Thermal conductivity ISO 8302 (KD2 Pro)

ﬁed using the Kolmogorov–Smirnov test (p > 0.05), allowing the use of parametric methods based on split-plot experimental design. Signiﬁcant diﬀerences were further analyzed by the Duncan multiple comparison test.

3. Results

then allowed to dry under air circulation in a shaded area for an additional two days. They were rotated once or twice per day to improve moisture evaporation. After one month, all samples except the glue-based ones were oven-dried at 105°C for 48 hours. Glue-based specimens were dried at 50°C for 48 hours. The prepared specimen sets are shown in Fig. 1. Water absorption and water reabsorption behaviour of the hemp fractions were examined separately. For this purpose, 600 g of material (100 g from each fraction shown in Fig. 2) was dried at 105 °C for 48 hours, soaked for 48 hours, and weighed twice daily to monitor moisture releases. Statistical evaluations were conducted using IBM SPSS v25. Normal distribution of data was veri-

The results presented in this section provide the comparative mechanical, thermal, and ﬁre performance of hemp-based composites, directly supporting the main objective of evaluating their suitability for sustainable building applications.

3.1. Water absorption and moisture retention

The results of water absorption and reabsorption of hemp products at the end of 5, 7 and 10 days with reference to oven dry weights. In the experiments on water-moisture properties, it was observed that in the natural state of hemp products, the least moisture was found in the coarse splinter (10.07%) and the most moisture was found in the ﬁber (20.08%). In the water impregnation experiment (48 hours, mains water and 20–25 °C ambient temperature), the amount and rates of water absorption were found to be quite high (Table 2). Although the fraction of hemp presented high capacit of water absorption, ranging

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Fig. 2. Hemp products used for water/moisture properties. Table 3. Time-dependent water absorption and water return values of hemp.

Coarse splinter/stem 100 Coarse shiv (T1) 100 Medium shiv (T2) 100 Fine shiv (T3) 100 Powder (T4) 100 Fiber 100 Tot./Aver. 600

48 hours water absorbed 5 days dried 7 days dried 10 days dried Humidity, % Weight, g Water, % Weight, g Water, % Weight, g Water, % Weight, g Water, %

83.28. 20.08

from 63% (coarse splinter) to 315% (powder) after 2 days immersion, moisture release of ﬁne fractions was relatively slow, retaining up to 96% moisture after 10 days drying. The result of water absorption and moisture retention was shown in Table 3.

3.2. Unit weights

The dry unit weights of hemp-based composites ranged from 330 to 1050 kg/m3 , indicating that all materials fall within the lightweight category (Table 4). The lowest unit weight was observed in the glue-based composite (330 kg/m3 , followed by lime

putty and natural hydraulic lime composites (<500 kg/m3 ). Only one mixture exceeded 1000 kg/m3 , which was the clay-based cubes. The relationship between diﬀerent binder materials and dry unit weights of the specimens formed using traditional binders with hemp additives was examined and the statistical diﬀerence between diﬀerent binders and dry unit weights was found to be very signiﬁcant (p < 0.01). As a result of the multiple comparison analysis performed to determine this difference, it was determined that the dry unit weight values of the clay binder material were statistically lower than those of the other binder materials.

GLK LK1 NHLK1 CLP1 LP2 PLK LK2 NHLP1 NHLK2 NHLP3 NHLP2 CLP2 CemK LP1 CLK1

Glue + hemp-cube Lime putty+hemp-cube1 Natural hydraulic lime+hemp-cube1 Clay-hemp-platter1 Lime putty+hemp-platter2 Plaster + hemp-cube Lime putty+hemp-cube2 Natural hydraulic lime+hemp -platter1 Natural hydraulic lime+hemp -cube2 Natural hydraulic lime+hemp -platter3 Natural hydraulic lime+hemp -platter2 Clay+hemp-platter2 Cement + hemp-cube Lime putty+hemp-platter1 Clay+hemp-cube1

0.333 ± 0.006a 0.437 ± 0.006ab 0.457 ± 0.046ab 0.550 ± 0.010bc 0.613 ± 0.006cd 0.626 ± 0.086cd 0.635 ± 0.059cd 0.663 ± 0.067cd 0.703 ± 0.029de * 0.725 ± 0.044def 0.748 ± 0.010def 0.820 ± 0.020ef 0.870 ± 0.156f 1.055 ± 0.021g

* Plaques with P1 and P3 at the end are 30 × 30 × 3 cm, plaques with P2 are 30 × 20 × 3 cm, cubes with K, K1, K2, K3 are 15 × 15 × 15 cm. *There is a statistical diﬀerence between the averages shown in the same column with diﬀerent letters. *Natural hydraulic lime + hemp-plate3 (NHLP3) sample was not included in the statistical analysis because it was produced as a spare sample. 0.01 < p < 0.05 signiﬁcant * p < 0.01 very signiﬁcant **,

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3.4. Thermal conductivity coefficient “k”(W/m·K)

Fig. 3. Compressive strength test and longitudinal-transverse strain measurement.

3.3. Mechanical behaviour

The compressive strength tests were carried out using a standard testing machine (2000 kN capacity) in the laboratories of Ondokuz Mayıs University, Department of Civil Engineering. All tests were performed on cube specimens with a side length of 15 cm. Since the device was not equipped with longitudinal and transverse strain gauges, two needle dial gauges were mounted to measure vertical and horizontal strain (Fig. 3). According to the mechanical properties obtained, the transverse and longitudinal strain rates, Poisson’s ratios and compressive stress changes of the specimens are presented in Fig. 4. According to the compressive test results, the average proportional changes in the volume and dimensions of the specimens are shown in Fig. 5. The highest compressive strength was found to be 24.8 kg/cm2 (2.43 MPa) in the set produced from cement and hemp products, whereas the lowest tensile value was 5.5 kg/cm2 (0.54 MPa) in the set using natural hydraulic lime. The average strengths of the other specimens produced were 6 kg/cm2 (0.59 MPa) for glued, 9 kg/cm2 (0.88 MPa) for plastered, 12 kg/cm2 (1.18 MPa) for lime, 13 kg/cm2 (1.27 MPa) for lime + silica sand + brick clay and 18 kg/cm2 (1.77 MPa) for clay specimen.

The coeﬃcient of thermal conductivity was measured with a KD2 Pro device. The obtained coeﬃcients were compared with the coeﬃcient of thermal conductivity (k) of 10 diﬀerent materials with good insulation properties or directly used as “insulation materials”. Samples used as reference for determining the coeﬃcient of thermal conductivity values are given in Fig. 6. The average values of the measurement results made on the samples and the reference material measurements are given in Table 5. Four diﬀerent hemp samples have a thermal conductivity coeﬃcient between 0.065–0.069, and ﬁve diﬀerent hemp samples have a thermal conductivity coeﬃcient between 0.072–0.085 W/m·K (equivalent to the measured natural pumice) and are considered as materials that can be reproduced as “insulation materials”. Only ﬁve of the 15 diﬀerent hemp samples had a thermal conductivity coeﬃcient in the range of 0.115-0.243 W/m·K. The sample with the highest thermal conductivity coeﬃcient of 0.243 W/m·K was the sample produced with water-based glue with the lowest unit volume weight (330 kg/m3 ). Although the glue-based composite had the lowest unit weight (330 kg/m3 ), it exhibited the highest thermal conductivity (0.243 W/m·K). This counterintuitive result is related to the polymeric PVAc binder, which forms continuous solid bridges between hemp particles. These solid bridges create uninterrupted heat-transfer pathways despite the low bulk density. Similar behaviour has been observed in bio-based composites containing organic adhesives, where polymer continuity increases thermal conductivity independent of density. When the results of the study on the determination of the usability of the samples formed using traditional binders with hemp additives as insulation elements were examined, the relationship between

Fig. 4. Variation of mechanical properties in the error bars.

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Fig. 5. Size and volume changes of the mixtures with pressure.

Fig. 6. Materials for which reference measurements were made for thermal conductivity (a: Iso-wall, b: Sandwich panel, c: Bims hollow core, d: Fiberboard, e: PS foam-cement coated). Table 5. Average thermal conductivity coefficients of hemp and reference samples. Description Heat 24–26 °C, Specimen r2 = 0.9984–0.9999 name* (k = W/m·K)

Thermal conductivity Reference (Heat 26 °C, value (aver. ± Average r2 = 0.9961–0.9996) std. deviation k = W/m·K (k = W/m·K))

LK2 CLP1 LP1 NHLK2 NHLP2 NHLK1 PLK CLP2 NHLP3 LK1 NHLP1 CemK LP2 CLK1 GLK

0.07. ± 0.0001abc

0.073 ± 0.0058abcd 0.077 ± 0.0058abcd 0.083 ± 0.0153abcd 0.084 ± 0.0055abcd 0.087 ± 0.0116abcde

0.13. ± 0.0001e

Lime putty+hemp-cube2 Clay+hemp-platter1 Lime putty+hemp-platter1 Natural hydraulic lime+hemp-cube2 Natural hydraulic lime+hemp -platter2 Natural hydraulic lime+hemp-cube1 Plaster + hemp-cube Clay+hemp-platter2 Natural hydraulic lime+hemp -platter3 Lime putty+hemp-cube1 Natural hydraulic lime+hemp -platter1 Cement + hemp-cube Lime putty+hemp-platter2 Clay+hemp-cube1 Glue + hemp-cube

Iso-wall-PS Foam-White Sandwich panel-Foam ﬁller PS Foam-Cement covered Iso-wall-XPS Foam-blue PS Foam- Cement Covered-Range Iso-wall-Natural pumice Bims Hollow Styrofoam reinforced concrete Fibreboard (2.5 cm) Cement Binder Pumice

Average k = W/m·K 0.027 0.029 0.033 0.034 0.059 0.074 0.104 0.143 0.152 0.172

*The nomenclature given in the components section refers to the materials that make up the components (Cem-Cement, CL-Clay, NHL-Natural hydraulic lime, GL- Polyvinyl Acetate Glue, PL-Plaster, L-Lime putty), P1 indicates a 30 × 30 × 3 cm plate and K indicates a 15 × 15 × 15 cm cube.

the diﬀerent binder materials used and the thermal coeﬃcient values was examined and the statistical diﬀerence between the diﬀerent binders and the thermal coeﬃcient values was found to be very signiﬁcant (p < 0.01). As a result of the multiple comparison analysis performed to determine this diﬀerence, it was determined that the internal carbonization progression of lime binder material was statistically higher than the other binder materials.

3.5. Fire performance

The temperature resistance of the hemp products used in the experiments (staple types, ﬁbers and splinters) were tested in their natural state and in the binder/compounding agent. This study was carried out to determine the relationship between ﬂaming combustion temperature and non-ﬂaming combustion temperature studied in the literature.

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Table 6. Burning temperature resistance of hemp products. Combustion temperature (°C)

In order to determine the combustion values of hemp products, the staple types and ﬁber samples were subjected to incineration in a muﬄe furnace. T1 (Thick), T2 (Medium), T3 (Fine), T4 (Very ﬁne powder), T5 (Fiber) and T6 Splinter (Stalk) samples were used in the study. These samples were prepared without using any binder/compounding agent and 5 grams of material was used. Before the start of the experiment, the muﬄe furnace was preheated at 200°C and all materials were placed in the muﬄe furnace at the same time. The combustion temperature of the materials used in the experiment was taken as the temperature values at which partial or complete charring was observed. The obtained combustion/charring temperatures are given in Table 6. No ﬂaming combustion was observed since the experiment was conducted in a closed environment. In order to exemplify the building materials that can be obtained by mixing hemp products with binder/combining materials, clay was used as a binder, lime (lime putty and powdered plaster lime) and plaster plaster were used as binders. Considering that a muﬄe furnace will be used in the study, the samples were produced as 10 × 10 × 10 cm cubes. The combustion temperature of the four diﬀerent types of materials subjected to the experiment was recorded as the tempera-

ture at which charring was observed. The obtained combustion/charring temperatures are given in Table 6. At the determined carbonization temperature, it was observed that the samples carbonized by decreasing from the outside to the inside. Therefore, the eﬀect of gradual temperature increase was investigated to determine the amount of charring progression. Plaster plaster specimens were not included in the next experimental group because they lost their integrity at 300°C. 8 specimens of each combination with 3 diﬀerent combinations were prepared and subjected to the experiment with an initial temperature of 260°C, increasing by 20°C up to 400°C and waiting for 20 minutes at each temperature value. Before the materials were placed in the muﬄe furnace, they were dried in an oven at 105°C for 48 hours and their dry weights were measured. Protection was provided with aluminum foil to prevent material loss in the muﬄe furnace (foil weight was eliminated in weighing). Each sample set was placed in the muﬄe furnace at the speciﬁed temperature for 20 minutes, then removed, cooled and weighed. The weight values obtained are given in Table 7. It was observed that there was a linear relationship in the weight changes of the clay-hemp blended samples against temperature and the weight changes of the samples

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Table 7. Weights (g) of dry samples at 260–400 °C temperature and 20 min time. Clay+Hemp

Fig. 7. Weight changes of the samples for 260–400 °C temperature and 20 min time.

decreased as the temperature value increased. There was no linear relationship between temperature and weight changes in the lime putty-hemp and powdered lime-hemp mixtures. It could not be determined whether the temperature eﬀect was directly eﬀective on weight changes. The weight change rates of the samples at the end of the determined temperature and time are given in Fig. 7. Visual inspection of the samples removed from the muﬄe furnace and weighed according to the gradual temperature increase showed that the charring progress was not the same everywhere. For this reason, it was decided to determine the progression values of this carbonization with larger (10 × 10 × 10 cm cube) samples. At 400 °C constant temperature, charring progress values were determined and recorded for 20, 40 and 60 minutes. The carbonization progress of the samples was found by taking 5 measurements from the sample surface. The carbonization forms of the samples are given in Table 8 and the average measurements of the carbonization progress are given in Table 9. As a result of the multiple comparison analysis performed to determine this diﬀerence, it was de-

Table 8. Visuals of the combustion state of 10 × 10 × 10 cm cube samples at 400 °C. Waiting time (min)

termined that the internal carbonization progress of lime binder material was statistically higher than the other binder materials. The statistical data of the combustion progress of the binder materials are given in Table 10.

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Table 9. Burning distances of 10 × 10 × 10 cm Cube samples from outside to inside at 400 oC. Clay + Hemp

Table 10. Statistical representation of the combustion progress of the materials. Specimen

* Diﬀerent superscript letters in the same row indicate statistically signiﬁcant diﬀerences (p < 0.05).

0.01. < p < 0.05: signiﬁcant (); p < 0.01: very signiﬁcant (**).*

Table 11. Statistical data of charring at different holding times at 400 °C constant temperature. Holding time (min)

* Diﬀerent superscript letters in the same row indicate statistically signiﬁcant diﬀerences (p < 0.05). Table 12. Statistical data for different holding times and material combustion interaction at constant temperature. Parameter Edge

1.555c ± 0.395 3.600ab ± 0.659 0.495d ± 0.324 2.005c ± 1.003 3.895b ± 0.605

1.380cd ± 0.379 3.985a ± 0.857 0.600d ± 0.441 3.215b ± 0.677 4.890a ± 0.155

2.500bc ± 0.412 3.000ab ± 0.515 0.930d ± 0.466 4.000ab ± 0.320 4.500ab ± 0.280

Diﬀerent superscript letters in the same row indicate statistically signiﬁcant diﬀerences (p < 0.05).

0.01. < p < 0.05: signiﬁcant (*); p < 0.01: very signiﬁcant (**).*

The statistical diﬀerence between the diﬀerent holding times of the samples at constant temperature was found to be very signiﬁcant (p < 0.01) for both internal and edge charring progress. As a result of the multiple comparison analysis performed to determine this diﬀerence, it was found that the holding time of 60 minutes at 400 °C resulted in statistically higher inner and edge charring progress compared to the other holding times. The statistical data for the holding time at constant temperature are given in Table 11. The statistical diﬀerence between the materials was found to be very signiﬁcant (p < 0.01) for internal carbonization progression and signiﬁcant (p < 0.05) for edge progression. As a result of the multiple comparison analysis, it was determined that the lime binder material showed statistically higher internal carbonization progression at constant temperature compared to the other binder materials. The statistical data for the interaction between different holding times and materials are presented in Table 12.

3.6. Statistical analysis

The study investigated the usability of samples produced with traditional binders incorporating hemp additives as insulation materials. The relationship between the type of binder used and the resulting compressive strength was analyzed. Regression analysis was conducted to examine the correlation between the compressive stress values of samples prepared with diﬀerent binders across various pressure ranges and the predicted strength values at those pressures. Based on the regression analysis, predictive equations for compressive strength at diﬀerent pressure ranges were established. The statistical data corresponding to these predictive equations are presented in Table 13. The compressive stress values at diﬀerent pressure ranges were found to be statistically signiﬁcant (p < 0.01) in mixtures prepared with all binder materials. In order to determine the relationship between diﬀerent pressure ranges and compressive stress, regression analysis results were analyzed and linear equation

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Table 13. Prediction equations obtained as a result of regression analysis. Binder Cement Lineer Glue Lineer Lime Lineer Plaster Lineer Lime putty Lineer Lime putty + silica Lineer

estimation was performed for each binder material. The obtained pressure-tension graphs are given in Fig. 8.

4. Discussion

The results indicate that hemp-based materials absorb water rapidly but release moisture more slowly. Fine hemp fractions showed particularly high water absorption rates and slower moisture release, aligning with previous ﬁndings on the hydrophilic nature of hemp [1]. This behaviour suggests that hemp-based materials may require additional precautions in high-humidity environments, yet they remain suitable for applications in low-humidity or interior conditions. Overall, the water-moisture performance conﬁrms the importance of improving

long-term durability through appropriate binder selection or surface modiﬁcation. Tests on composite specimens produced with diﬀerent binders showed that unit volume weight remained below 1000 kg/m3 in 14 out of 15 mixtures. In three mixtures, those incorporating water-based, lime putty, or natural hydraulic lime, the unit weight dropped 500 kg/m3 . These ﬁndings are consistent with previous hempcrete studies reporting similarly low densities [26, 27]. Lightweight materials are advantageous for seismic-prone regions, as reduced mass contributes to lower inertial forces. Therefore, the low density of the composites supports their potential use in lightweight partition walls or non-load-bearing structural elements. Mechanical test results showed that cementbased composites exhibited the highest compressive strength (24.8 kg/cm2 ≈ 2.43 MPa), aligning with a previous study [16]. Natural hydraulic lime produced the lowest strength values (5.5 kg/cm2 ≈ 0.54 MPa), while glue, gypsum, and clay-based composites exhibited intermediate performance. The inclusion of hemp increased deformability and improved elastic response, as all mixtures exceeded the deformation limits of the standard testing machine. Observed dimensional and volumetric changes also reﬂect the compressible nature of hemp ﬁbers within the matrix. Taken together, the mechanical ﬁndings indicate that while hemp composites are not suitable for loadbearing systems, they perform suﬃciently well for lightweight structural and architectural applications.

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Thermal conductivity values ranged broadly between 0.051 and 0.243 W/m·K. The sample with the lowest conductivity (0.051 W/m·K) contained high hemp content and low lime putty, and was compacted under pressure, aligning with high-performance insulation materials reported in literature [23, 24]. Several mixtures (0.065–0.085 W/m·K) demonstrated thermal performance comparable to natural pumice. Conversely, the glue-based composite exhibited the highest thermal conductivity (0.243 W/m·K) despite having the lowest unit weight (330 kg/m3 ). This counterintuitive behaviour can be explained by the continuous polymer bridges formed by the PVAc binder, which create eﬀective heat-transfer pathways regardless of bulk density. Such phenomena have been similarly reported in organic adhesive– based composite systems. Overall, the results show that hemp-based composites can provide competitive insulation performance when appropriate binder proportions and compaction strategies are used. The calculated ignition temperature of hemp shiv (206 °C) aligns with studies reporting ignition thresholds slightly below those of wood and cellulose-based materials [28]. In this study, ﬂameless combustion tests showed that raw hemp charred at 238–265°C, while binder-based composites charred at 300–385°C. This improvement in charring resistance indicates that binder incorporation contributes to thermal stability and may oﬀer additional protection in ﬁre scenarios. The controlled charring depths observed in larger specimens provide valuable insight into ﬁre-related material behaviour, which should be considered in future design guidelines. Overall, the discussion conﬁrms that the physical, mechanical, thermal, and ﬁre performance results collectively support the main objective of the study: evaluating the suitability of hemp-based composites produced with traditional binders for sustainable and lightweight building applications. The varying performance across binder types demonstrates the importance of binder selection, mixture ratio optimization, and moisture management strategies. While the composites show strong potential for insulation, partitioning, and low-impact structural use, further improvements in moisture resistance and long-term durability are required for broader practical implementation.

5. Conclusion

This study investigated the physical, mechanical, thermal, and ﬁre behaviour of hemp-based composites, produced with six diﬀerent traditional binders. All mixtures exhibited lightweight characteristics

with unit weights ranging from 330 to 1050 kg/m3 . The glue-based composite had the lowest unit weight (330 kg/m3 ), followed by mixtures containing lime putty and natural hydraulic lime (<500 kg/m3 ). Thermal conductivity values varied between 0.051 and 0.243 W/m·K, and six mixtures showed lower conductivity than natural pumice (k = 0.074 W/m·K). The best thermal performance was observed in limeputty composites (0.051 W/m·K). In contrast, the glue-based composite showed the highest thermal conductivity despite its low density, which is attributed to the continuous polymer bridges created by the PVAc binder. Combustion tests revealed that raw hemp materials char between 238-265°C, while binder-based composites indicated increased charring resistance (300–385 °C). For 10 × 10 × 10 cm cube samples exposed to 400 °C, charring progression ranged from 3 to 5 cm after 60 minutes. Compressive strengths ranged between 5.67 kg/cm2 (0.56 MPa) and 24.69 kg/cm2 (2.42 MPa), with cement-based composites achieving the highest values. Due to the deformation limits of the testing device, measured values represent minimum strengths rather than ultimate capacities. The inclusion of hemp contributed to greater deformability and improved elasticity in all mixtures. Overall, the ﬁndings conﬁrm that hemp-based composites oﬀer promising performance for nonload-bearing construction, insulation applications, and lightweight building elements, particularly in seismic-prone regions where reduced mass is advantageous. However, high water absorption and slower moisture release underline the need for further improvement in durability. Future research should focus on enhancing moisture resistance, optimizing binder combinations, and investigating long-term hygrothermal performance to support wider application in sustainable building systems.

Acknowledgments

This study was supported by Ondokuz Mayıs University with the project number PYO.MUH. 1908.21.014. We would like to thank the Rectorate of Ondokuz Mayıs University for the support. We would like to thank Ali Galip Baş, General Manager of Samsun Makina Sanayi for the steel sample mold production support. We would like to thank Prof. Dr. Mustafa Özbey and Research Assistant Prof. Fevzi Şahin.

Conflicts of interest

JOURNAL OF SUSTAINABLE CONSTRUCTION MATERIALS AND TECHNOLOGIES 2026;11:186–198

Author contributions

Conceptualization, A.A. and F.B.; methodology, S.A. and H.A.S.; investigation, A.A. and A.K.A.; data curation, A.A.; writing-original draft preparation, A.A.; writing-review and editing, F.B. and I.I.; supervision, F.B. All authors have read and agreed to the published version of the manuscript.

Data availability statement

The data supporting this study are available from the corresponding author upon reasonable request.

This research was supported by Ondokuz Mayıs University (Project No. PYO.MUH.1908.21.014).

Use of AI for writing assistance AI tools (ChatGPT and Gemini) were used solely for grammar checking and language editing. All scientiﬁc content, analysis, and conclusions were generated by the authors.

Not applicable. All data generated or analysed during this study are included in this published article. 17.

1. Stevulova N, Cigasova J, Estokova A, Terpakova E, Geﬀert

A, Kacik F, et al. Properties Characterization of Chemically Modiﬁed Hemp Hurds. Materials. 2014 Dec;7(12):8131–50. doi:10.3390/ma7128131.

2. Shahzad A. Hemp ﬁber and its composites – a review.

J Compos Mater. 2012 Apr 1;46(8):973–86. doi:10.1177/ 0021998311413623. 3. Magniont C. Contribution à la formulation et à la caractérisation d’un écomatériau de construction à base d’agroressources [thesis] [Internet]. Toulouse 3; 2010 [cited 2025 Nov 13]. Available from: https://theses.fr/2010TOU30101.

4. Stevulova N, Schwarzova I. Inﬂuence of alternative binder on

the properties of hemp hurds composites. Czas Inż La˛dowej Śr Archit J Civ Eng Environ Archit. 2017;z. 64, nr 4/I. doi:10. 7862/rb.2017.192.

5. Nováková P. Use of technical hemp in the construction

industry. MATEC Web Conf. 2018;146:03011. doi:10.1051/ matecconf/201814603011.

6. Arrigoni A, Pelosato R, Melià P, Ruggieri G, Sabbadini S,

Dotelli G. Life cycle assessment of natural building materials:

the role of carbonation, mixture components and transport in the environmental impacts of hempcrete blocks. J Clean Prod. 2017 Apr 15;149:1051–61. doi:10.1016/j.jclepro.2017. 02.161. Bumanis G, Vitola L, Pundiene I, Sinka M, Bajare D. Gypsum, Geopolymers, and Starch—Alternative Binders for Bio-Based Building Materials: A Review and Life-Cycle Assessment. Sustainability. 2020 Jan;12(14):5666. doi:10.3390/su121456 66. Souza E. ArchDaily [Internet]. 2020 [cited 2025 Nov 13]. Hemp Concrete: From Roman Bridges to a Possible Material of the Future. Available from: https://www.archdaily.com/ 944429/hemp-concrete-from-roman-bridges-to-a-possiblematerial-of-the-future. Demir İ, ElmalıM. Organi̇k Atiklarin Yapi Malzemesi̇ Olarak Kullanabi̇li̇rli̇ği̇ni̇n Araştirilmasi. Mühendis Bilim Ve Tasar Derg. 2020 Dec 25;8(4):1303–11. doi:10.21923/jesd.781554. Arslan MA, Aktaş M. İnşaat Sektöründe Kullanılan Yalıtım Malzemelerinin Isıve Ses YalıtımıAçısından Değerlendirilmesi. Politek Derg. 2018 Jun 1;21(2):299–320. doi:10.2339/politeknik.407257. Ip K, Miller A. Life cycle greenhouse gas emissions of hemp– lime wall constructions in the UK. Resour Conserv Recycl. 2012 Dec 1;69:1–9. doi:10.1016/j.resconrec.2012.09.001. Shewalul YW, Quiroz NF, Streicher D, Walls R. Fire behavior of hemp blocks: A biomass-based construction material. J Build Eng. 2023 Dec 1;80:108147. doi:10.1016/j.jobe.2023. 108147. Wu Y, Xia C, Cai L, Shi SQ, Cheng J. Water-resistant hemp ﬁber-reinforced composites: In-situ surface protection by polyethylene ﬁlm. Ind Crops Prod. 2018 Feb 1;112:210–6. doi:10.1016/j.indcrop.2017.12.014. Haghighatnia T, Abbasian A, Morshedian J. Hemp ﬁber reinforced thermoplastic polyurethane composite: An investigation in mechanical properties. Ind Crops Prod. 2017 Dec 1;108:853–63. doi:10.1016/j.indcrop.2017.07.020. Acikel H. The use of miscanthus (Giganteus) as a plant ﬁber in concrete production. Çomak B, Bideci A, Salli Bideci Ö. Eﬀects of hemp ﬁbers on characteristics of cement based mortar. Constr Build Mater. 2018 Apr 30;169:794–9. doi:10.1016/j.conbuildmat.2018.03. 029. Arnaud L, Gourlay E. Experimental study of parameters inﬂuencing mechanical properties of hemp concretes. Constr Build Mater. 2012 Mar 1;28(1):50–6. doi:10.1016/j.conbuildmat. 2011.07.052. Evrard A, Herde AD, Minet J. Dynamical interactions between heat and mass ﬂows in Lime-Hemp Concrete. In: Research in Building Physics and Building Engineering. CRC Press; 2006. Tajvidi M, Motie N, Rassam G, Falk RH, Felton C. Mechanical Performance of Hemp Fiber Polypropylene Composites at Diﬀerent Operating Temperatures. J Reinf Plast Compos. 2010 Mar 1;29(5):664–74. doi:10.1177/0731684408100266. Nguyen TT, Picandet V, Amziane S, Baley C. Inﬂuence of compactness and hemp hurd characteristics on the mechanical properties of lime and hemp concrete. Eur J Environ Civ Eng. 2009 Oct 1;13(9):1039–50. doi:10.1080/19648189. 2009.9693171. Kaya S, Oğuz ME. TESİSAT YALITIMINDA UYGUN MALZEME SEÇİMİ. 2015. Delannoy G, Marceau S, Glé P, Gourlay E, Guéguen-Minerbe M, Amziane S, et al. Durability of hemp concretes exposed to accelerated environmental aging. Constr Build Mater. 2020 Aug 20;252:119043. doi:10.1016/j.conbuildmat.2020. 119043.

JOURNAL OF SUSTAINABLE CONSTRUCTION MATERIALS AND TECHNOLOGIES 2026;11:186–198

23. Pretot S, Collet F, Garnier C. Life cycle assessment of a hemp

concrete wall: Impact of thickness and coating. Build Environ. 2014 Feb 1;72:223–31. doi:10.1016/j.buildenv.2013.11.010.

24. Shea A, Lawrence M, Walker P. Hygrothermal performance of

an experimental hemp–lime building. Constr Build Mater. 2012 Nov 1;36:270–5. doi:10.1016/j.conbuildmat.2012.04.123.

25. Vėjelis S, Lekūnaitė-Lukošiūnė L, Šeputytė-Jucikė J. Loose Fill

Material from Hemp Shives and Binding Material for Thermal Insulation and Structural Use. Mater Sci Forum. 2017;908:134– 8. doi:10.4028/www.scientiﬁc.net/MSF.908.134.

26. Barbhuiya S, Bhusan Das B. A comprehensive review on

the use of hemp in concrete. Constr Build Mater. 2022 Jul 25;341:127857. doi:10.1016/j.conbuildmat.2022.127857.

27. Magwood C. Essential Hempcrete Construction: The Complete

Step-by-Step Guide. New Society Publishers. 2016. 123 p. 28. Babrauskas V. Ignition Handbook: Principles and applications to ﬁre safety engineering, ﬁre investigation, risk management and forensic science [Internet]. 2014 [cited 2025 Dec 1]. Available from: http://elpub.bib.uni-wuppertal. dereceive/duepublico_mods_00000783.

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Aygun, A.; Birinci, F.; Aytac, S.; Ayan, A.K.; Sahin, H.A.; Isildak, A.I. Mechanical, Thermal and Fire Behaviour of Hemp-Based Composites with Different Binders for Sustainable Building Applications. Journal of Sustainable Construction Materials and Technologies 2026, Vol. 11, pp. 9. https://doi.org/10.29187/2458-973X.1216

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Mechanical, Thermal and Fire Behaviour of Hemp-Based Composites with Different Binders for Sustainable Building Applications

Abstract

1. Introduction

2. Material and methods

2.1. Specimen preparation

3. Results

3.1. Water absorption and moisture retention

83.28. 20.08

3.2. Unit weights

3.4. Thermal conductivity coefficient “k”(W/m·K)

3.3. Mechanical behaviour

0.07. ± 0.0001abc

0.13. ± 0.0001e

3.5. Fire performance

0.01. < p < 0.05: signiﬁcant (); p < 0.01: very signiﬁcant (**).*

0.01. < p < 0.05: signiﬁcant (*); p < 0.01: very signiﬁcant (**).*

3.6. Statistical analysis

4. Discussion

5. Conclusion

Acknowledgments

Conflicts of interest

Author contributions

Data availability statement

1. Stevulova N, Cigasova J, Estokova A, Terpakova E, Geﬀert

2. Shahzad A. Hemp ﬁber and its composites – a review.

4. Stevulova N, Schwarzova I. Inﬂuence of alternative binder on

5. Nováková P. Use of technical hemp in the construction

6. Arrigoni A, Pelosato R, Melià P, Ruggieri G, Sabbadini S,

23. Pretot S, Collet F, Garnier C. Life cycle assessment of a hemp

24. Shea A, Lawrence M, Walker P. Hygrothermal performance of

25. Vėjelis S, Lekūnaitė-Lukošiūnė L, Šeputytė-Jucikė J. Loose Fill

26. Barbhuiya S, Bhusan Das B. A comprehensive review on

27. Magwood C. Essential Hempcrete Construction: The Complete

Share and Cite

Related Articles

Mechanical, Thermal and Fire Behaviour of Hemp-Based Composites with Different Binders for Sustainable Building Applications

Abstract

1. Introduction

2. Material and methods

2.1. Specimen preparation

3. Results

3.1. Water absorption and moisture retention

83.28. 20.08

3.2. Unit weights

3.4. Thermal conductivity coefficient “k”(W/m·K)

3.3. Mechanical behaviour

0.07. ± 0.0001abc

0.13. ± 0.0001e

3.5. Fire performance

0.01. < p < 0.05: signiﬁcant (); p < 0.01: very signiﬁcant (**).*

0.01. < p < 0.05: signiﬁcant (*); p < 0.01: very signiﬁcant (**).*

3.6. Statistical analysis

4. Discussion

5. Conclusion

Acknowledgments

Conflicts of interest

Author contributions

Data availability statement

1. Stevulova N, Cigasova J, Estokova A, Terpakova E, Geﬀert

2. Shahzad A. Hemp ﬁber and its composites – a review.

4. Stevulova N, Schwarzova I. Inﬂuence of alternative binder on

5. Nováková P. Use of technical hemp in the construction

6. Arrigoni A, Pelosato R, Melià P, Ruggieri G, Sabbadini S,

23. Pretot S, Collet F, Garnier C. Life cycle assessment of a hemp

24. Shea A, Lawrence M, Walker P. Hygrothermal performance of

25. Vėjelis S, Lekūnaitė-Lukošiūnė L, Šeputytė-Jucikė J. Loose Fill

26. Barbhuiya S, Bhusan Das B. A comprehensive review on

27. Magwood C. Essential Hempcrete Construction: The Complete

Share and Cite

Related Articles