Mechanical and Microstructural Characterization of Rammed Earth Stabilized with Five Biopolymers

This study aims to check the compatibility of a selection of waste and recycled biopolymers for rammed earth applications in order to replace the more common cement-based stabilization. Five formulations of stabilized rammed earth were prepared with different biopolymers: lignin sulfonate, tannin, sheep wool fibers, citrus pomace and grape-seed flour. The microstructure of the different formulations was characterized by investigating the interactions between earth and stabilizers through mercury intrusion porosimetry (MIP), nitrogen soprtion isotherm, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The unconfined compressive strength (UCS) was also evaluated for all stabilized specimens. Three out of five biopolymers were considered suitable as rammed earth stabilizers. The use of wool increased the UCS by 6%, probably thanks to the combined effect of the length of the fibers and the roughness of their surfaces, which gives a contribution in binding clay particles higher than citrus and grape-seed flour. Lignin sulfonate and tannin increased the UCS by 38% and 13%, respectively, suggesting the additives’ ability to fill pores, coat soil grains and form aggregates; this capability is confirmed by the reduction in the specific surface area and the pore volume in the nano-and micropore zones

Compositional characterization of Etruscan earthen architecture and ceramic production

This study presents the results of new research into Etruscan technology for earthen architecture as well as ceramic production in the upper Tiber Valley in central Italy, using as a case study the Etruscan settlement of Col di Marzo (Perugia). It determines the compositional differences of the raw material employed as building material and for ceramic production by X-ray powder diffraction (XRD), thermogravimetric analysis and differential thermal analysis (TG-DTG), Fourier-transform infrared analysis (FTIR) and geotechnical analyses. The research also advances the knowledge of ceramic manufacturing technology, with a focus on impasto production, at Col di Marzo between the fifth and mid-third centuries bce and the surrounding territory on the left bank of the River Tiber. The compositional analysis of building material compared with the ceramics provides answers to questions related to their sourcing and deepens the understanding of the exploitation of natural resources

Compositional characterization of Etruscan earthen architecture and ceramic production

The purpose of this paper is to present the results of new research into Etruscan technology for earthen architecture as well as ceramic production in the upper Tiber valley in Central Italy, using as case-study the Etruscan settlement of Col di Marzo (Perugia). The study aims to determine the compositional differences of the raw material employed as building material and for ceramic production by XRD, TG-DTG, FTIR and geotechnical analyses. The research also advances the knowledge of ceramic manufacturing technology, with a focus on impasto production, at Col di Marzo between the 5th to the mid-3rd century BC and the surrounding territory on the left bank of the Tiber. The compositional analysis of building material compared to the ceramics provides answers to questions related to their sourcing and deepens the understanding of the exploitation of natural resources

Hemplime Blocks: Innovative Solution for Green Buildings in Italy

In the last years, the attention to an eco-friendly development of the building sector has increased the use of green materials, mainly because the construction sector is one of the most polluting. The hemplime block represents a valid option in this direction: it is a valuable product to improve the sustainability of the building. Like any new product, the main issues are given by the absence of specific rules, starting from the production phase until the installation. For this reason, themain objective of thiswork is to take a first step toward the long process of identifying possible guidelines for the production and the testing phase of the products to achieve a CE (European Commission) certification. Another essential aspect to clarify is the definition of indications for the laying phase of the prefabricated blocks. This study significantly contributes to reduce uncertainties and skepticism about this technology. With these objectives, some experimental tests have been carried out to verify the reliability of the data declared in the datasheets of hemplime blocks produced in Italy, justifying any incongruity. This study also investigates other aspects of hemplime block, such as the main pathologies that may affect this technology during its lifetime and themaintenance operations necessary to restore the product. Furthermore, the thermal performance of a wall was studied in a climatic chamber to study its behavior in conditions similar to service life

Hygrothermal behaviour of hemp-lime walls: the effect of binder carbonation over time

Bio-based building materials are produced by recovering agricultural biomasses which are used as vegetal aggregate to replace traditional ones and realize more sustainable building materials. This study focuses on hemp-lime that is made by mixing a lime-based binder with hemp shives i.e. the waste of industrial hemp cultivation. The work aims to evaluate the effect of the maturation of hemp-lime on its hygrothermal performances. Specifically, the binder undergoes carbonation reaction through which the strength of the material and its hygrothermal properties develop. With this aim, two experimental campaigns were carried out on an experimental wall built using prefabricated hemp-lime blocks: the first few months after the construction and the second one after 3 years. The wall, equipped with hygrothermal sensors, was subjected to cycles at varying relative humidity values and fixed temperatures applied with the help of a climatic chamber. The cycles were performed at 23 °C and 35 °C to focus on the performances of the material in conditions comparable to those of the Mediterranean climate. The results prove that hygrothermal performances improve with maturation, which could be due to the carbonation of the binder and to the reduction of the initial moisture content. Numerical simulations of the experimental tests were implemented using the software WUFI® aiming at confirming the experimental methodology and also the possibility of simulating the behavior of such innovative material in dynamic regime. The proceeding of carbonation was proved through X-ray diffraction (XRD) and thermogravimetric (TG-DTG) analyses of samples having different maturation times

Hemp-lime buildings: thermo-hygrometric behaviour of two case studies in North and South Italy

In the framework of Circular Economy policies aimed at reducing the consumption of raw materials, shives, an agricultural by-product of hemp cultivation, have gained a renovated life in the construction sector; new building materials, suitable for various executive techniques, have been developed exploiting the excellent thermal insulating properties of shives. When this vegetal material is mixed with a mineral binder such as lime or cement, the mixture is usually referred to as hemp-lime. In Italy, the use of hemp-lime blocks and the development of new production chains dates back only to about the last decade, while other European countries have more long-lasting experiences. In order to assess the potential benefits of hemp-lime blocks in the construction sector, it is necessary to evaluate the performance of these materials in situ, i.e. on the construction site, to obtain fundamental data to ensure that consumers and designers receive trustworthy and relevant information on products and their durability. This research work aims to be a solid base for the development of future guidelines and/or regulations at national and international level, in order to guarantee the maximum diffusion of this type of product. Then, a study plan has been carried out regarding the functionality of hemp-lime blocks in masonry, layered with finishing plaster made of fine hemp shives, to evaluate the in situ thermo-hygrometric building performance. In particular, experimental methods were developed and measurements were carried out on two structures, one in northern Italy and one in southern Italy, and precisely in Sicily, focusing the study on the performances of the walls subjected to warm Mediterranean climates