Experimental Investigation on the Bond Behavior of a Compatible TRM-based Solution for Rammed Earth Heritage

ABSTRACT

Despite the current awareness of the high seismic risk of earthen structures, little has been done so far to develop proper strengthening solutions for the rammed earth heritage. Based on the effectiveness of TRM for masonry buildings, the strengthening of rammed earth walls with externally bonded fibers using earth-based mortar is being proposed as a compatible solution. In this context, the investigation of bond behavior was conducted by means of direct tensile tests, pull-out tests and single lap-shear tests. The specimens were prepared using earth-based mortars and two different types of meshes (glass and nylon) while considering different-bonded lengths. The direct tensile tests on TRM coupons showed the high capacity of the nylon mesh in transferring stresses after cracking of the mortar. The pull-out tests highlighted that in the case of glass fiber mesh, the bond was granted by friction, while the mechanical anchorage promoted by the transversal yarns granted the bond of the nylon mesh. Finally, the single lap-shear tests showed that the adopted earth-based mortar seems to limit the performance of the strengthening.

KEYWORDS:

• Bonded length
• compatible strengthening
• direct tensile test
• pull-out test
• rammed earth
• single lap-shear test
• textile reinforced mortar

Acknowledgments

This work was partly financed by FEDER funds through the Operational Programme Competitiveness Factors (COMPETE 2020) and by national funds through the Foundation for Science and Technology (FCT) within the scope of project SafEarth - PTDC/ECM-EST/2777/2014 (POCI-01-0145-FEDER-016737). The support from grants SFRH/BD/131006/2017 and SFRH/BPD/97082/2013 is also acknowledged. Acknowledgments are addressed to master students Cristina Barroso, Aidarbek Stamov and Reza Talakoobi.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Fundação para a Ciência e a Tecnologia [PTDC/ECM-EST/2777/2014,SFRH/BD/131006/2017,SFRH/BPD/97082/2013].