Global database of FRP-to-masonry bond strength tests

Quantifying the bond strength between fibre-reinforced-polymer (FRP) composites and substrates is essential to the design of FRP retrofit systems. This paper collates a database of 1583 individual tests across 56 published experimental campaigns investigating the FRP-to-masonry bond strength through shear pull-tests. Included in the database is all available information characterizing the test arrangement, geometric and mechanical properties of the constituents, as well as the failure load and failure mode.


a b s t r a c t
Quantifying the bond strength between fibre-reinforced-polymer (FRP) composites and substrates is essential to the design of FRP retrofit systems. This paper collates a database of 1583 individual tests across 56 published experimental campaigns investigating the FRP-to-masonry bond strength through shear pull-tests. Included in the database is all available information characterizing the test arrangement, geometric and mechanical properties of the constituents, as well as the failure load and failure mode.

Data
Through an extensive literature review, an experimental database of 1583 individual shear pulltests on masonry specimens was compiled from across 56 published studies .

Description of a pull-test
A generic pull-test specimen consists of a fibre-reinforced-polymer (FRP) composite plate adhesively bonded to a substrate prism over a particular lap length. The substrate prism can be either a unit prism consisting of a single brick or block, or a masonry prism consisting of individual units bonded together using mortar joints. Both of these are shown in Fig. 1.
A test is performed by applying an increasing tensile force to the FRP plate until the plate eventually debonds from the prism. Typical debonding failure involves the detachment of the plate along with a layer of the substrate material. Alternate failure modes (other than substrate debonding can include FRP rupture, failure at the adhesive, prism material failure (compression, tension or shear), or a combination of these.
The test results summarised in the compiled database include the maximum load and a description of the observed failure mode. Note that the various possible forms of instrumentation can include the measurement of strain along the plate using strain gauges, slip (displacement) between the plate and the prism, or full-field deformation by techniques such as digital image correlation. However, as the focus of the database is the bond strength, these are beyond the scope of the data.

Substrate materials
Tested substrate materials include clay brick, limestone, tuff, concrete block, calcium silicate brick, sandstone, and mortar specimens. Data for each test includes the mechanical properties of the substrate material including its compressive and tensile strength. The tensile strength is further subcategorised in terms of the type of test performed as either direct, flexural, splitting, or unspecified.

FRP materials
The database covers both externally-bonded (EB) and near-surface-mounted (NSM) retrofits, as shown in Fig. 2. The different possible reinforcement shapes include EB sheets (a.k.a. fabrics) installed by wet lay-up (see Fig. 2a), and pre-formed rectangular strips and round bars used in NSM applications ( Fig. 2b and c).

Test arrangements
Tests within the database are split approximately evenly between single-lap and double-lap arrangements, with the latter being further subcategorised into a single block and a double block variant. Each of these are shown in Fig. 3. Note that for double-lap arrangement the reported ultimate load corresponds to the load in a single lap, P as shown in Fig. 3.
The majority of tests in the database use monotonic loading. However, a small number of tests used cyclic loading comprising separate loading, unloading and reloading phases. Failure Mode Reported failure mode(s): "Substrate Debonding", "FRP rupture", "Adhesive failure", "Prism failure", or a combination. 38 Comment Provides comment regarding any provided information that differs from the original paper

Data inclusion/exclusion criteria
The database includes only tests conducted under standard conditions, that is, where the plate is bonded directly to the masonry substrate and subjected to quasi-static loading. The data therefore excludes the following: Specimens subjected to effects such as temperature and moisture [5,25,29,33,41,46,51,52]; Tests in which additional anchorage between the FRP and substrate was provided. For example those with nails, fans or cogs [9,18,24,30,32,55]; Tests in which the FRP was bonded to plaster instead of directly to the masonry substrate [9,39,42,55,56]; Non-quasi-static loading conditions such as impulse loads [54]; and Plates manufactured from textile-reinforced mortars or fibre-reinforced cementitious mortars.
These exclusion criteria were applied to individual tests, and as such, control specimens found in the aforementioned studies are still included. Note that some studies have intentionally opted not to report the failure load for tests where the mode of failure was not by interfacial debonding-such tests are still included as long as the mode of failure was reported. Additionally, where the same tests were identified to have been reported in multiple sources, they are only included once.
The database also includes tests with the following special conditions, which are specifically identified in the database: Tests with confining pre-compression (30 tests) [13,19]; Curved specimens (10 tests) [18]; and Specimens that were repaired after an initial test and re-tested (98 tests) [34,40,50].

Description of information provided in the database
The compiled database is provided as a CSV (comma separated variable) spreadsheet in Supplementary Material accompanying this article. Table 1 summarises the data provided for each individual pull-test. Note that fields entered as '-' mean that the data is either not relevant to the particular test or that it was not specified in the original paper.

Transparency document. Supporting information
Transparency data associated with this article can be found in the online version at https://doi.org/ 10.1016/j.dib.2018.08.111.

Appendix A. Supporting information
Supplementary data associated with this article can be found in the online version at https://doi. org/10.1016/j.dib.2018.08.111.