Bond strength characterization of commercially available grouts for masonry

Abstract

h i g h l i g h t sBond strength is one of the most important properties of grout injection technique. Strength depends significantly on the substrate and its condition. Different results were obtained for the same grout varying the support and the moisture content of the substrate. An average tensile bond strength of 0.8 MPa at 28 days was obtain for three types of stone for one of the studied grouts. A higher compression strength does not necessarily mean higher values of bond strength capacity. a b s t r a c tHeritage masonry structures often show signs of deterioration due to ageing, soil settlements, extreme events or other actions. Repairing these structures using grout injection is an interesting technique since it preserves the historical character of the existing materials, even if filling voids and bringing a bonding addition. A high-performance grout for use in these structural repairs should meet several performance criteria, including fluidity, strength, compatibility and durability. The main objective of this study is to assess the bond characteristics of four commercially available (CA) grouts available in Europe, as this is possibly the most needed mechanical performance of grouts. The bond mechanism was studied in composite grout/stone specimens, as the shear bond strength of the grout-stone interface is the main property affecting the behaviour of grouted walls. In-depth characterization of the tensile strength of the interface between grout and stone required the preparation of specimens with the selected CA grouts and three usual stones in historical buildings: limestone, schist and yellow granite. The moisture content of the stones was also varied, as this is difficult to control in real case studies. Therefore, the tests were performed with dry, moist and saturated stones. Significant differences were found between the different grouts, stressing the need for adequate material selection.

Preliminary Valorization of Climatic Conditions Effects on Curing of Air Lime-Based Mortars for Restorative Applications in the Pasargadae and Persepolis World Heritage Sites

“…Bond strength is one of the most important properties of the restorative materials and a preliminary valorization check of bonding had to be placed prior to more detailed laboratorial characterizations. Bonding, strength, and durability of restorative mortars for real applications depend significantly on the substrate and its condition [24]. Bond strength depends significantly on the substrate and its condition.…”

Rehabilitation of Porous Building Components and Masonry by MICP Injection Method

“…Moreover, the different pore structures of the masonry could be the reason for the different results. It is important that the injection material is compatible with the sample, which depends on a number of factors such as the characteristics of the pores [26]. The pore size plays a role and determines the capacity of water absorption [27].…”

Enhanced Documentation and Evaluation of Grouting Process, through the Fusion of Non-Destructive Testing and Evaluation Information—The Case Study of the Katholikon of the Monastery of Panagia Varnakova

“…Grouting is a non-reversible intervention, in the sense that once the grout is solidified within the masonry internal void network, it is impossible to remove it without disassembling the masonry. Hence, significant research for historic structures is being conducted regarding the composition [34][35][36][37][38][39], the physicochemical [39,40] and rheological characteristics of the grouts [41][42][43], their impact on the mechanical behavior of the grouted masonry [44][45][46][47], the criteria for the compatibility of the grouts with historic materials and the issues of sustainability [48][49][50][51], as well as the grouting procedure. The assessment of the efficacy of grouting is largely based on laboratory testing of the grout prior to grouting, in conjunction with in situ mainly destructive testing post-grouting [31,33].…”