EN 1170 Precast Concrete Products - Test Method for Glass Fibre Reinforced Cement

The European standard “EN 1170 Precast concrete products - Test method for glass fibre reinforced cement” consists of the following subsections published under the same title:

• The standard “EN 1170-1 Part 1: Measurement of matrix consistency - Slump test method” describes a test method that allows to check the workability of the mixture and the suitability of the water/cement ratio (suitability for pumping and compaction) in glass fibre reinforced cement. For the purposes of this standard, matrix refers to the composition of glass fibre reinforced cement without fibres. It consists of a mixture of sand, cement, water and any admixtures and additives. When interpreting the results, the optimum value is determined according to the production method and the type of product to be produced. It is defined during the creation of the mix design. If the result obtained does not comply with the defined optimum value, a second test is carried out to verify the result before changing the composition (e.g. without changing the amount of water).
• The standard “EN 1170-2 Part 2: Measurement of fibre content in fresh glass fibre reinforced cement - Washing test” describes a test method for verifying the fibre content and uniformity of distribution in finished products and for monitoring fibre consumption. The optimum value for interpreting the results is determined by the specification and is a function of the end use. If the result obtained does not comply with the specified value, a second test is carried out to verify the information before making adjustments to the process. The deviation between the measured values ​​can be evaluated for each of the three sieves as shown in the standard appendix (Annex B).
• The standard “EN 1170-3 Part 3: Measurement of the fibre content of sprayed glass fibre reinforced cement” describes a test method for verifying the fibre content of sprayed glass fibre reinforced cement during production. The fibre content expressed as a percentage by weight is determined by the equation given in the standard. The optimum value for interpreting the results is determined by the specification and is a function of the end use. If the result obtained does not agree with the specified value, a second test is carried out to verify the information before making any adjustments to the process. The specified fibre content (average fibre content) is determined by the manufacturer as a function of the production variability so that the glass fibre content of the products is at least equal to the specified value (Annex A).
• The standard “EN 1170-4 Part 4: Measurement of flexural strength - Simplified flexural test method” describes a test method to be applied to glass fibre reinforced cement, to verify compliance with the flexural strength specification, to assess the smoothness of the production process and to control the uniformity of compaction.

At the start of the test, a sample panel without a mounting layer (i.e., made entirely of glass fiber reinforced cement ) is prepared by spraying or premixing onto a flat board under the same conditions as the actual production it represents. After 24 hours, it is demolded and stored under the same conditions as the actual production it represents until it is six days old. Eight test pieces are cut at 50 mm from the edges at the locations shown in the standard. Test pieces can also be cut on the day of demolding. The dimensions of the test pieces, in width and length, are given in this standard for a testing machine with a fixed distance between supports and for a testing machine with an adjustable distance between supports. When the eight test pieces have been stored for six days, they are immersed in a tank filled with water at 20 degrees plus/minus 2 degrees for 24 hours, thus being stored for seven days during the test. The test should be performed no more than half an hour after the test pieces are removed from the water. The fracture stress due to bending is calculated in megapascals using the equation given in the standard.

• The standard “EN 1170-5 Part 5: Measurement of flexural strength - Full bending test method” describes a test method for determining the stress and deformation performance at the limit of proportionality and at failure of a glass fibre reinforced cement composition subjected to bending. This method is also used to determine the relationship between the 28-day conventional strength and the 7-day strength for a given glass fibre reinforced cement composition.

At the beginning of the test, sample panels are prepared successively on two flat boards, without any coating layer (solid glass fiber reinforced cement only), under the same conditions as the actual production they represent, with spray or premix. After 24 hours, the two sample panels are removed from the mold and stored for 6 days under the same conditions as the actual production they represent. The test pieces can also be cut on the day of demoulding. Eight test pieces are cut at 50 mm from the edges from the positions shown in the figure given in the standard. The dimensions of the test pieces are shown in width and length. The changes in the thickness of the test pieces should not exceed 5 percent and should be limited to 0,5 mm. The thickness of the test piece may need to be changed to meet this requirement.

When the test pieces from the first panel are kept for six days, they are immersed in a tank filled with water at 20 degrees plus/minus 2 degrees for 24 hours, thus allowing seven days for the test. When the test pieces from the second panel are kept for six days, they are kept in the laboratory for 20 days at 3 degrees plus/minus 60 degrees and 5 percent plus/minus 21 percent relative humidity, thus allowing 27 days. Then, for the 28-day test, they are immersed in water for 20 hours at 2 degrees plus/minus 24 degrees. In either case, the test should be carried out no more than half an hour after the test pieces are removed from the water. After removal from the water and before the test, the test pieces are wiped with a damp cloth to remove any water from their surfaces.

The standard “EN 1170-6 Part 6: Determination of water absorption by immersion and determination of dry density” describes a test method for determining the dry density and water absorption of a specific glass fiber reinforced cement composition. When interpreting the results of the immersion water absorption test, the immersion water absorption, expressed as a percentage by mass, is determined using the equation given in the standard . For polymer-containing formulations, it is calculated for 24 hours and 7 days. When interpreting the dry density test results, the equation given in the standard is used. The results depend on the properties (such as sand granulometry, polymer content) and workmanship (compaction) of the glass fiber reinforced cement composition.

• The standard “EN 1170-7 Part 7: Measurement of extremes of dimensional change due to moisture content” describes a test method to determine the maximum dimensional changes (permanent hydraulic shrinkage and reversible expansion) of a glass fibre reinforced cement composition attributable to changes in water content to which products exposed to the elements can be subjected.

At the beginning of the test, two location pads (on both faces of each test piece) are attached using an epoxy resin suitable for gauge fixation. Each face is marked. Each test piece is weighed. The distance between the pads on each test piece face is measured.

When measuring residual shrinkage from drying, three test pieces are placed in a ventilated oven set at 33 degrees plus/minus 3 degrees. The test pieces are placed aside so that the hot air can circulate properly over the two measuring surfaces. After 21 days, the test pieces are removed from the oven and placed in the laboratory at 20 degrees plus/minus 3 degrees. After 6 hours of fixation, each test piece is weighed and the distance between the pads on each side is measured.

When measuring reversible expansion by immersion, three test pieces are placed in a tank filled with water at 20 degrees plus/minus 2 degrees. The test pieces are set aside and the test pieces are completely immersed. After 20 hours of immersion in water at 2 degrees plus/minus 96 degrees, the test pieces are removed and wiped with a damp cloth. Then, each test piece is weighed and the distance between the pads on each side is measured.

When interpreting the shrinkage value results, the residual shrinkage value of each test piece is the arithmetic average of the value obtained for each surface and is calculated by the equation given in the standard. The shrinkage value of the glass fiber reinforced cement composition is characterized by the arithmetic average of the shrinkage values ​​of three test pieces.

When interpreting the expansion value results, the expansion value of each test piece is equal to the arithmetic mean of two values, each calculated from the equation given in the standard. The expansion value of the glass fiber reinforced cement composition is characterized by the arithmetic mean of the expansion values ​​of three test pieces.

• The standard “EN 1170-8 Part 8: Cyclic abrasion type test” describes a test method to determine the influence of environmental factors such as water and temperature on the change of mechanical properties for a given glass fibre reinforced cement formulation (components in the formulation and their proportions). For other exposure conditions, for example where freezing, thawing and the effect of dissolving salt occur, this test method is adapted.

When starting the test, 2 x 8 test pieces are taken as shown in the figure “Location and identification of test pieces” given in the standard. EN 1170-5 standard is valid for taking the test pieces and determining their lengths.

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