Injection Grout Laboratory Testing

A component of Injection Grouts for the Conservation of Architectural Surfaces: Research and Evaluation
Two people in lab coats hold a tube attached to an instrument in a laboratory

Beril Bicer-Simsir (left) GCI Associate Scientist, and Giorgio Torraca, conservation scientist, testing injectability device, which assesses the degree of ease with which a grout can be injected through a column of crushed brick, travertine, or sand

In 2006 the project team initiated a laboratory testing program, which included the following stages.

Stage 1

Tests of Injection Grouts for Architectural Surfaces

In most cases, standardized tests—including ASTM, DIN, EN, UNI, among others— have been developed for portland cement–based mortars and grouts but not specifically for injection grouts used in the conservation of architectural surfaces that are mostly lime- or hydraulic lime-based. The team identified existing test methods for mortars and grouts, evaluated the properties under investigation and grouped them under four areas. In some cases, more than one standard test method was evaluated for determining a specific property of the hydraulic lime-based injection grouts. The test methods examined in this study are as follows:

Materials analysis:

  • elemental analysis (X-ray fluorescence, environmental scanning electron microscopy coupled with energy-dispersive X-ray analysis)
  • compositional analysis (X-ray diffraction)
  • soluble salt content analysis (ion chromatography)
  • surface area (gas adsorption–BET)
  • particle size distribution (laser diffraction spectrometry)
  • organic compound analysis (Fourier-transform infrared spectroscopy)

Testing of working properties:

  • injectability (NF EN 1771)
  • flow by Marsh cone (ASTM C 393, UNI 11152, EN 196-3)
  • viscosity (ASTM D 4016, DIN 53018, UNI 11152)
  • water retention (DIN 18 555-7, ASTM C 1506)
  • expansion and bleeding (ASTM C 940)

Testing of properties during setting and curing:

  • initial setting time by Vicat needle (ASTM C 191, C 807, C 953, EN 196-3, UNI 11152)
  • shrinkage (ASTM C 474)

Testing of cured-state properties:

  • shear bond strength
  • flexural-tensile and compressive strength (EN 196-1)
  • splitting-tensile strength (NF EN 1771)
  • content of soluble salts (IC)
  • water absorption (Normal 7/81, 11/85)
  • porosity (RILEM I.1)
  • water vapor permeability (Normal 21/85)

Stage 2

Selection of Grouts to Evaluate Test Methods

The commercial and custom-mixed grouts were selected to provide a wide range of working and performance properties to evaluate the effectiveness of test methods and for their availability and common use in the field.

Stage 3

Determination of Modifications to Existing Testing Protocols

Many standard tests are not immediately suitable for testing injection grouts used in the conservation of architectural surfaces. When possible, existing standard test methods were modified and adapted for this purpose.

Stage 4

Development of New Test Methods

Project team developed laboratory and field test methods when no tests were available to evaluate specific properties of injection grouts or when modifications to existing methods were not found to be satisfactory.

Stage 5

Compilation and Publication of Test Results

Based on the testing development carried out, the project team prepared a series of test methods for laboratory and field use.

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