BS/EN 1544-2006 pdf download.Products and systems for the protection and repair of concrete structures — Test methods — Determination of creep under sustained tensile load for synthetic resin products (PC) for anchoring of reinforcing bars.
4.11 An apparatus capable of applying a sustained tensile load over a period of time (A typical apparatus is given in Figurel).
NOTE Any systems providing a permanent tensile load of (50 ± 1.0) kN can be used.
4.12 A device, interlocked with the rebar during the whole test, connected to one or more displacement sensors capable of measuring relative movement between the anchored bar and a fixed reference point on the test block to an accuracy of ± 0.01 mm.
5 Specimen preparation
5.1 Composition of the concrete test specimens
The test specimens shall be cast from concrete type C (0,40) as specified in EN 1766.
5.2 Preparation of moulds
Test specimens shall be produced in a room or chamber maintained at (21 ± 2) °C.
Moulds shall be non-deformable and of minimum dimensions 400 mm x 400 mm x 250 mm for a single test, or in multiples of the 400 mm dimensions for more than one test. Before filling the inner surface of the mould it should be covered with a thin film of non reactive release material to prevent the concrete from adhering to the mould.
5.3 Preparation of concrete test blocks
The concrete shall be placed and immediately compacted in three layers of approximately equal thickness and vibrated using a 25 mm diameter concrete vibrator in such a way as to produce full compaction of the concrete with neither excessive segregation nor laitance. For a block for a single test the vibratory operation shall be carried out at four points, each position being equidistant and at about 125mm from the two adjacent faces. For larger blocks with dimensions greater than 400 mm x 400 mm x 250 mm vibration shall be carried out at the same four positions, and also at intermediate points on a square grid pattern of approximately 150 mm.
The vibration should be applied for the minimum time necessary for the full compaction of the concrete. The vibrator should be in a vertical position and not allowed to touch the sides or bottom of the mould.
The concrete specimens shall be cured in the moulds for at least 72 h after casting at (21 ± 2) C, either under polyethyiene sheeting or at not less than 95 % relative humidity, then demoulded and cured until at least 28 days after casting. During curing the test blocks shall be stored at (21 ± 2) °C, in air at a relative humidity of not less than 95 %.
The anchoring product is prepared in accordance with the manufacturers instructions.
Before mixing up the anchoring product, the constituents are stored under standard laboratory climate
(21 ± 2) °C and (60± 10) % RH for at least 24 h.
5.4.2 Preparation of the concrete for anchoring
Seven days before carrying out the anchoring operation, each concrete test-piece shall be removed from the humidity chamber or room and then stored in a chamber or room maintained at (21 ± 2) C and (60 ± 10) % relative humidity.
On the day of the intended anchoring operation, a hole shall be drilled by a rotary percussive or diamond drill, as specified by the manufacturer, in the centre of the 400 mm x 400 mm face of the block. For larger blocks (for multiple tests) holes are drilled at a minimum distance of 200 mm from any edge and at least 400 mm from any other hole.
Holes shall be drilled to a depth of (150 ± 3) mm. The hole diameter shall be 20 mm, unless specified otherwise by the manufacturer.
Immediately after the drilling operation the hole(s) shall be cleaned in accordance with manufacturers instructions: the anchoring operation shall then be undertaken.
6 Procedure
6.1 CarryIng out the anchoring operation
Before use the rebars shall be prepared in accordance with manufacturers instructions; the prepared rebars, the anchoring product, and the equipment and tools required for mixing and placing shall be stored for at least 24 h in a room or chamber maintained at (21 ± 2) C and (60 ±10) % relative humidity.
The product shall be mixed and placed, and the rebars installed, strictly In accordance with the manufacturer’s instructions.
Each rebar, set to the base of its hole, shall be located and supported along the centre line of the hole by the centering device.
NOTE The efficacy of the product is dependent on the care exercised during use, and therefore the manufacturer’s recommendations should be followed
6.2 Storage of test-pieces after carrying out the anchoring operation
The test pieces shall be stored undisturbed for the minimum curing time recommended by the manufacturer. and then up to the time of the test, at (21 ± 2) C and (60 ±10) % relative humidity.BS/EN 1544-2006 pdf download.