Search

In order to meet sustainable development goals, global policies are strongly oriented towards the recovery of local materials such as agricultural waste. In this context, a new biosourced compressed earth brick (CEB) has been produced with bio-shell aggregates of Cocos nucifera (CN) and Canarium schweinfurthii (CS), added in equal proportions for various mixtures. The main objective is to study, on one hand, the effect of CN and CS aggregates on the mechanical behaviour and the thermo-physical properties of the CEB. On the other hand, durability of CEB was investigated in terms of hydric stability, abrasion resistance and hygro-thermomechanical behaviour. Mixtures were prepared using earthen material and 0, 5, 10 and 15 wt% CNCS, with 8 wt% cement CEM II-B-LL 42.5, respectively. Wet and dry compressive strengths are evaluated versus compaction pressure (2.5, 5, 7 and 10 MPa). The increase of CNCS aggregate content induced a reduction of the compressive strength in both wet a\nd dry situations whatever the compaction pressure. The samples with 5 wt % CNCS and 8 wt % cement, however, offered performances close to reference samples without CNCS aggregates. The reverse trend was found for thermal conductivity: thermal conductivity of the bio-sourced CEB is below 1 W·m-2·K-1 which means good insulating performances. It is noted that the modified CEB have relatively low water absorption, which contribute to a good durability. Hygro- and thermo-mechanical tests showed however a quasi-linear decrease of compressive strength when the humidity of the environment increases but also when the temperature rises. At the end, to obtain more accurate properties by prediction, some machine learning models were used. [ABSTRACT FROM AUTHOR]

This work presents an extensive experimental characterization of two different ceramic brick blocks with hydraulic contact interface (cement mortar or lime mortar), at different heights, during the drying process. First, a laboratory characterization of the building material used (ceramic bricks and different mortars) was carried out to determine their hygrothermal, mechanical and thermal properties, namely, bulk porosity and density, water vapor permeability, capillary absorption, retention curve, moisture diffusivity as a function of moisture content and thermal conductivity. Finally, the moisture transfer in multi-layered systems was analyzed in detail taking into account the hydraulic contact between the building elements. The results showed an increase of the drying time constant for the materials with cement mortar interface compared to the lime mortars materials, and that as further away from the base the interface is located, higher is the drying time constant. The hydraulic interface (imperfect contact) could significantly retard the flow of moisture transport. i.e., the assumption of perfect hydraulic contact may result in significant error in predicting moisture transport in building materials. [ABSTRACT FROM AUTHOR]

The paper aims to present a new insulating material based on cork aggregates and cement designed for building applications. Samples are prepared by mixing natural cork aggregates, sand, cement and water. Four cork volume dosages are considered, 0, 25, 50 and 75% (relative to the sand). Samples are characterised in terms of hardened density, compressive and flexural strength, as well as thermal conductivity and hydric properties (moisture content, vapour permeability, moisture buffering value and absorption by partial immersion). Results show that increasing cork granule amount tends to increase moisture retention and buffering value but decreases density, thermal conductivity and mechanical properties. Depending on the cork content, cork concrete mixture can be used as thermal insulator or as a structural component. [ABSTRACT FROM AUTHOR]