Resilient hemp shiv aggregates with engineered hygroscopic properties for the building industry

Hussain, Atif; Calabria-Holley, Juliana; Lawrence, Michael B.; Jiang, Yunhong

doi:10.1016/j.conbuildmat.2019.03.327

Cited by 11 publications

(7 citation statements)

References 34 publications

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“…In contrast, the EAPP mix shows almost negligible adsorption of water vapor on the surface at lower humidity levels. Moreover, the hysteresis between adsorption and desorption curves is hardly noticeable in the EAPP mix, meaning that microencapsulation has been able to protect the APP particles and eliminate their hygroscopic property responsible for their sensitivity to moisture [34]. The water vapor sorption isotherms of the intumescent powders are shown in Figure 3.…”

Section: Resultsmentioning

confidence: 99%

Fire Performance of Intumescent Waterborne Coatings with Encapsulated APP for Wood Constructions

et al. 2021

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In this work, intumescent coatings were prepared for protection of wood from fire. The fire-retardant chemical ammonium polyphosphate (APP) is known to have poor resistance to water and high humidity as it is hygroscopic in nature. To improve the water resistance, durability and fire resistance of the intumescent coating, APP was modified using a hybrid organic-inorganic polysiloxane encapsulation shell prepared by the sol–gel method. The physical and chemical properties of the intumescent mix containing microencapsulated ammonium polyphosphate (EAPP) particles were characterized by X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), water absorption, dynamic vapor sorption (DVS) and thermogravimetric analysis (TGA). The EAPP mix showed 50% reduction in water absorption, 75% reduction in water vapor sorption and increased thermal stability when compared to the APP mix. The intumescent coatings were applied on wood samples, and their fire performance was evaluated using a cone calorimeter test. The intumescent coatings containing EAPP mix showed better fire retarding properties with longer time to ignition, lower heat release rate and shorter heat release peak when compared to the coating without EAPP mix. The prepared intumescent coating shows higher resistance to water and moisture, and it has great potential to be used in bio-based construction industry for enhancing the fire resistance of wood.

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Section: Resultsmentioning

confidence: 99%

Fire Performance of Intumescent Waterborne Coatings with Encapsulated APP for Wood Constructions

et al. 2021

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“…Being highly porous, hemp shive exhibits excellent water absorption behaviour [28,46,47,51,52]; test results showed that shives are capable of absorbing water equivalent to two-thirds of their own weight within 10 min of immersion reaching a saturation level of 95% [28]. This behaviour can be attributed to the presence of the macro pores due to the hemicellulose and lignin content.…”

Section: Absorption Behaviourmentioning

confidence: 99%

“…This behaviour can be attributed to the presence of the macro pores due to the hemicellulose and lignin content. Presence of larger macro pores in hemp shive allows it to absorb water at a faster rate than a smaller pore size that slowly fills up with water [28,46,47,51,52]. Properties of other common internal curing agents such as LWA, which have smaller pore structure, suggest they will continue to absorb water for three days, but will likely reach their maximum after 48 h [29].…”

Section: Absorption Behaviourmentioning

confidence: 99%

An Experimental Evaluation of Hemp as an Internal Curing Agent in Concrete Materials

Nazmul,

Sainsbury,

Al-Deen

et al. 2023

Materials

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The construction industry is facing increased demand for adopting sustainable ‘green’ building materials to minimise the carbon footprint of the infrastructure sector to meet the United Nations 2030 Sustainability Goals. Natural bio-composite materials such as timber and bamboo have been widely used in construction for centuries. Hemp has also been used in different forms in the construction sector for decades for its thermal and acoustic insulation capability owing to its moisture buffering capacity and thermal conductivity. The current research aims to explore the possible application of hydrophilic hemp shives for assisting the internal curing of concrete materials as a biodegradable alternative to currently used chemical products. The properties of hemp have been assessed based on their water absorption and desorption properties associated with their characteristic sizes. It was observed that, in addition to its excellent moisture absorption capacity, hemp released most of its absorbed moisture into the surroundings under a high relative humidity (>93%); the best outcome was observed for smaller hemp particles (<2.36 mm). Furthermore, when compared to typical internal curing agents such as lightweight aggregates, hemp showed a similar behaviour in releasing its absorbed moisture to the surroundings indicating its potential application as a natural internal curing agent for concrete materials. An estimate of the volume of hemp shives required to provide a similar curing response to traditional internal curing techniques has been proposed.

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“…In the capillary condensation domain (> 85% RH), the water uptake for corn bark was the highest due to the presence of a greater number of smaller pores inside it. Notably, only the sorption curves are shown in Figure 13; however, several authors [7,24,28,45,78,149] also took desorption measurements. All the authors observed a hysteresis phenomenon between the sorption and desorption curves.…”

Section: Figure 12mentioning

confidence: 99%

A Review of the Multi-Physical Characteristics of Plant Aggregates and Their Effects on the Properties of Plant-Based Concrete

Ratsimbazafy¹,

Laborel-Préneron²,

Magniont³

et al. 2021

RPM

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The use of plant aggregates obtained from agricultural co-products mixed with mineral binders to form eco-friendly insulating building materials has been initiated for a few years to bring environmentally friendly solutions to the construction sector. Several studies on different agro-resources have already been carried out, providing various information about the properties of plant aggregates and plant-based concrete. However, the characteristics of the agricultural co-product, which allow it to qualify as a plant aggregate for plant-based concrete, are not yet very clear despite the multitude of data, especially on hemp concrete. Therefore, it is important to gather numerous but very disparate pieces of information available in the literature concerning the properties of plant aggregates and their correlations with composites. This review is based on the results of 120 articles and aims to identify the characterization methods and the multi-physical properties of plant aggregates affecting those of plant-based concrete and to propose additional factors that could influence the properties of the composites. A total of 18 plant aggregates of different origins used for plant-based concrete have been listed in the literature. In France, hemp shiv is the most studied one, but its quantity is quite low unlike cereal or oilseed straws and wood transformation residues. With the existence of several characterization methods, properties like microstructure, particle size distribution, bulk density, water absorption capacity, and chemical composition of aggregates are easily and frequently determined. In contrast, data on the apparent density of particles, the skeleton density, and the hygro-thermal properties of aggregates are rare. The particle size, density, and porosity have been identified as important parameters influencing the properties of the composites. Other parameters related to the behavior of the aggregates under wet compaction and compression of their stacking can also predict the physical and mechanical properties of the obtained plant-based concrete. Dosages of the constituents should be preferred as formulation parameters for future studies assessing the impact of the aggregate properties on the composites.

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Resilient hemp shiv aggregates with engineered hygroscopic properties for the building industry

Cited by 11 publications

References 34 publications

Fire Performance of Intumescent Waterborne Coatings with Encapsulated APP for Wood Constructions

Fire Performance of Intumescent Waterborne Coatings with Encapsulated APP for Wood Constructions

An Experimental Evaluation of Hemp as an Internal Curing Agent in Concrete Materials

A Review of the Multi-Physical Characteristics of Plant Aggregates and Their Effects on the Properties of Plant-Based Concrete

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