Reduction of rammed earth's hygroscopic performance under stabilisation: an experimental investigation

Abstract

a b s t r a c tOne of the acknowledged qualities of rammed earth (RE) is its moisture buffering capacity. Recently, stabilisation of RE has become a common practice to improve the mechanical resistance but very little is known about the effect that stabilisation has on hygroscopic properties. The present study aims to fill this gap by understanding the role that stabilisation plays in the buffering and sorption capacity of RE. The use of alternative stabilisers such as fly ash and calcium carbide residue and a comparison with traditional unstabilised RE (URE) have also been investigated. Moreover, the effect of weathering, simulated by cyclic wetting-drying, on hygroscopic performance has been analysed. Moisture Buffer Value (MBV) testing, moisture and nitrogen adsorption-desorption isotherms and mercury intrusion porosimetry were performed on stabilised samples to examine microstructural phenomena responsible for behavioural changes. URE was confirmed to be a good-to-excellent passive air conditioner according to the MBV scale but its performance seemed to be highly influenced by the soil particle size distribution and mineralogy. Based on the experimental outcomes of the mixtures investigated, stabilisation had a detrimental effect on the moisture buffer capacity of rammed earth, likely due to the inhibition of the physico-chemical interactivity between moisture and clays. Weathering had a variable effect on the buffering capacity, depending on the availability of unreacted particles in the matrix.

Life cycle analysis of environmental impact vs. durability of stabilised rammed earth

“…A summary of all mixes is given in Table 1. Extensive microstructural investigations of Mixes 4, 5 and 6 were presented by the authors in [14,15]. CL, RCA and ELS particle size distributions (PSDs) are presented in Fig.…”

Assessing Cement Stabilized Rammed Earth Durability in A Humid Continental Climate

“…On the other hand, adding cement to the soil mix reduces the possibility of recycling the material [6]. Furthermore, the stabilization by cement reduces the passive air conditioning ability of earthen walls [7]. The cement industry is one of the two largest producers of carbon dioxide (CO 2 ), creating up to 8% of worldwide man-made emissions of this gas [1].…”

“…A surprisingly small number of documents include requirements regarding durability. On the other hand, in scientific literature there are a number of non-standard features related to durability and ecology, such as hygroscopic performance [7], ecological performance [33], hydrothermal properties [34], and water absorption [35]. The analysis of the table indicates that the most frequently standardized durability characteristics are resistance to erosion and linear shrinkage, regardless of the climatic zone of the country where a given standard was created.…”

Shear Parameters of Rammed Earth Material: Results from Different Approaches

“…e di raction patterns were recorded with a Bruker D8 di ractometer. e result (shown in Figure 3) reveals the presence of quartz (72.6%), albite (15.1%), illite (11%), and trace of vermiculite (1.3%) [24]. e Proctor optimum water content is of 12% (by weight), determined following the French standard [25].…”