Measurement of grout parameters
Table A.1 presents the measuring conditions, measuring devices, test procedures and units for measuring the principal grout parameters.
|1||Outflow time (Cone viscosity)||[s]||Marsh cone (funnel diameter = 4,75 mm),
Other flow cones (diameter = 8, 10, 12 mm)
|lab and site||N/A||A||A||see R1|
|2||Viscosity (dynamic or apparent)||[Pa·s]||Coaxial viscometer
lab and site
|A||A||N/A||see R1 and R2|
Baroïd mud balance
|lab and site||A||A||A|
|4||Cohesion, Yield, Shear strength||[Pa]||Coaxial viscometer, Rheometer,
Plate cohesion meter,
|lab lab and site||N/A||A||N/A||see R4|
|5||Water retention capacity||[m3]||Baroïd filter press (low pressure)||lab and site||N/A||A||A|
|6||Bleeding rate, Sedimentation||[%] or [m3/m3 ] for 2 hr||Measuring cylinder||lab and site||N/A||A||A||see R6|
|7||Workability||[mm]||Abrams cone||lab and site||N/A||N/A||A||see R7|
|8||Setting time||[s]||Overturned glass beaker, Vicat needle||lab and site||A||A||A||see R8|
|9||Hardening time||[s]||Vane test
Unconfined compression test
|lab and site||A||A||A||see R9|
|10||Hardening Deformation Final strength||Unconfined compression test with stress-strain record,
Triaxial test, Point load tests
|11||Durability||Mechanical: flow test
|12||Thixotropy||Rheometer, Viscometer, Hydrometer||lab||N/A||A||N/A||see R12|
|13||Syneresis||[Vol %]||Volume of water expelled from sample with time||lab||A||N/A||N/A||see R13|
|14||Shrinkage/expansion||[%] of vol, length||Shrinkage limit determination||lab and site||A||A||A||see R14|
|15||Granulometry||Particle size measurement||lab and site||N/A||A||A||see R15|
Sand column test
|site lab||A||A||N/A||see R16|
|N/A = not applicable/not generally used, A = applicable|
(R1) The rheological properties of a grout may be determined with the following equipment:
- flow cone (viscosity);
- rotary viscometer (viscosity and cohesion);
- dipping plate or pipe, ball harp, kasumeter (cohesion).
The air temperature, the temperature of the grout, the dimensions of the flow cone, the fill height and the outflow volume shall be stated. The value obtained is a function of viscosity and cohesion, and it should be noted that different combinations of viscosity and yield point can result in the same outflow time.
Mortars used for compaction grouting are not concerned.
(R2) The air temperature and the temperature of the grout shall be stated. The viscosity may be determined for a given rotational velocity or torque. Torque controlled rotary viscometers should be employed to assess the flow properties at low velocities and hence the penetrability of the grout. Where coaxial viscometers are not available on site, a correlation with cone values previously established in the laboratory may be used.
(R4) The design shall specify the apparatus to be used and the values to be achieved. Rheometers used for "cohesion" measurements should be torque controlled.
(R5) The design shall specify the pressure and duration of the test.
(R6) The bleeding (sedimentation) rate shall be determined in a cylinder of 1 000 ml volume with an inner diameter of 60 mm.
(R7) The testing method shall follow EN ISO 4109 and prEN 12382:1996.
(R8) The setting time is both temperature and volume dependent. According to the grouting application and the grout type, different tests are used to characterize this property:
- tilting or inverting the test cylinder and noting when the grout no longer behaves as a liquid;
- shaking the test receptacle slightly to see if the grout or gel comes away from the sides;
- carrying out a scaled down penetration test, with for example, the Vicat needle. The apparatus to be used and the values to be achieved shall be stated in the design.
(R9) The hardening time shall be defined in relation to a design strength value. The design shall specify the dimensions of the samples to be tested and the conditions of testing (rate of stress application, etc.).
(R10) The design shall specify the dimensions of the samples to be tested and the conditions of testing (rate of stress application, etc.).
(R11) The chemical and mechanical durability of a grout and the hardened grout shall be investigated under the in situ conditions of pH.
The mechanical stability can be determined in a flow test whereby water flows through a bore in a sample of hardened grout and the amount of material collected in a container is weighed after the test.
The chemical stability can be determined by a grinding test whereby the specimen is finely ground, kept for a few days in the aggressive ground water, and the volume measured at the end.
(R12) For determining the thixotropy, the rheometer shall allow recording of two continuous curves.
(R13) This test is applicable for sodium silicate gels.
(R14) Refer to national standards for the determination of shrinkage limits and expansion.
(R15) This parameter is of prime importance when using microfine products. The increase in size of grout particles due to hydration shall be taken into account when considering the particle size distribution curves of grouting constituents.
(R16) Penetrability tests may serve to demonstrate the ability of a given grout to penetrate a given ground, or as a means of quality control. An example of penetrability tests is given in the French Standard NF P 18 891.