A methodology for the mix design of earth bedding mortar

Abstract

Earth masonry is a good alternative to more conventional materials in order to reduce the environmental impact of building materials. However earth construction techniques mostly rely on bricklayers' experience, which is a hindrance to industrial development of this traditional know-how. This article proposes a methodology for the mix design of unstabilized earth bedding mortar based on mechanical criteria of the masonry and rheological criteria of fresh mortar. A test to characterize the shear strength of the masonry interface is specially investigated. The mechanical performances of the formulated mortar are then validated with laboratory scale characterization.

Shake table tests on 1:2 reduced scale masonry house with the application of horizontal seismic bands

“…Table 4 summarizes the shear resistance values for different interfaces. For the extruded earth block samples, the shear resistance was found to be 6.02 MPa, which is close to the cohesion value, c = 14 -15 kPa obtained for similar extruded earth blocks (Duriez et al, 2020;Reyes et al, 2019). The failure occurred at the interface between the mortar joint and block unit, but never within the mortar joints.…”

“…The coefficient value of 0.4, which represents the contribution of the shear strength due to compressive stress in the wall, is used as a constant for all types of masonry (Tomaževič, 2009) in cases where the frictional coefficient is unknown. However, the friction angle obtained from the shear test experiment at various normal stress using extruded earth block from same manufacturer and mud mortar was found to be 42ᵒ (Duriez et al, 2020). Given this friction angle, the coefficient value for frictional contribution to the shear strength would be 0.9 instead of 0.4 in Equation 1, which is close to the average coefficient of friction between brick and masonry used in the numerical model by (Gaetano et al, 2022).…”

“…To determine the shear resistance of the interface, three sandwich specimens were prepared using extruded earth block and mortar, and three samples were prepared using extruded earth block-concrete brick sandwiched with mortar. Due to the weak interface between the earth block and mortar, a simplified testing technique involving bucket loading tests (Duriez, Vieux-Champagne, Trad, Maillard, & Aubert, 2020) was utilized. The maximum force at the failure of the interface was recorded for each test.…”

Effect of paste content on long-term strength and durability performance of green mortars

“…To enhance the quality of mortar, several researchers have proposed different methods to design mortar mixtures [9][10][11][12]. Besides, the densified mixture design algorithm (DMDA) has been recognized as an effective method to improve the strength and durability of concrete [13], which may apply for mix design of the green mortars with consideration on both long-term strength and durability performance.…”