NOGUEIRA, RITA1; FERREIRA PINTO, ANA PAULA2; GOMES, AUGUSTO3

1) Research Assistant, IST-ICIST, Department of Civil Engineering, Architecture and Georesources, rita.nogueira@tecnico.ulisboa.pt

2) Assistant Professor, IST-ICIST, Department of Civil Engineering, Architecture and Georesources, anapinto@civil.ist.utl.pt

3 Associate Professor, IST-ICIST, Department of Civil Engineering, Architecture and Georesources, augusto@civil.ist.utl.pt

The drilling resistance test is a valuable tool, suitable for in situ characterization, as it provides the material strength profile in depth, with little intrusion. This unique feature enables assessing the strength and thickness of the layers in multilayer renders. Additionally, information about the bond quality between layers and between the whole render and masonry is provided. In this paper, four lime mortar renders in multilayer systems of two coats, were tested. Based on the analysis of the average values and dispersion of the drilling force measurements distribution, properties of each layer were assessed. Additionally, drilling resistance in layers was compared with drilling resistance and compressive strength both obtained in prisms and with superficial hardness in layers. The study enabled a better understanding of the important factors influencing drilling results.

Keywords: drilling resistance, lime mortars, multilayer renders, in situ characterization