GB/T 36262-2018Fiber reinforced polymer composite grids for civil engineering (English PDF)

3.1 Fiber reinforced polymer composite grids

a continuous grid-shaped composite product which is produced with continuous fiber by a certain process, such as pultrusion, pressure forming and vacuum forming, usually in the orthogonal bi-directional […]

7.3 Sampling rules

7.3.1 For appearance inspection and dimensional deviation, use single sampling and take 6 rolls randomly from each batch.

7.3.2 For tensile property and alkali resistance, use double sampling and take 6 rolls randomly each time.

7.4 Determination rules

7.4.1 When single sampling is used for appearance inspection and dimensional deviation, a batch is a pass if all samples taken are as required or only 1 roll is not as required; or else, it is a fail.

7.4.2 When all samples taken for the first time for tensile property and alkali resistance property are as required, then the batch is a pass; and when there are 2 rolls or more are not as required, then it is a fail. When 1 roll is not as required, then a second sampling is carried out, and it is a pass if the total number of samples not as required in two samplings is 1; or else, it is a fail.

8.2 Packaging

Composite grids shall be packaged using strong, flexible packaging materials.

Products shall be tied together closely to prevent impact and abrasion. The package shall be accompanied by product compliance certificate.

A.1 Scope

This test method specifies the test principle, test equipment, test piece preparation, test conditions, test procedures, calculation and result handling for the tensile property of composite grids.

This test method applies to the determination of tensile strength, tensile elasticity modulus and elongation at break of composite grids for civil engineering.

A.2 Test principle

Apply a tensile load at a constant speed along the axial direction of test pieces until it breaks or achieves the predetermined elongation.

A.3 Test equipment

A.3.1 Testing machine

The relative error of testing machine shall not exceed ± 1%.

A.3.2 Strain measurement equipment

The relative error of extensometer or strain gage for the measurement of elongation of composite grids shall not exceed ± 1%.

A.3.3 Sampling frequency

The sampling frequency of data acquisition system shall be less than 1 Hz.

A.4 Test piece preparation

A.4.1 Test pieces consists of a test part and an anchor part.

A.4.2 Test part. take not less than 40 times of grid segment width from test pieces as the measuring length.

A.4.3 Anchor part. fastener shall be fit for the geometrical shape of the section cut from composite grids' test piece, with the single-side anchoring length not less than 300 mm. […]

B.4.2 pH meter

pH meter for laboratory use, with the measuring range 0 ~ 14.00 and accuracy 0.01.

B.5 Test solution

The proportion of test solution is that each 1 L of deionized water is added with 118.5 g of Ca(OH)2, 0.9 g of NaOH and 4.2 g of KOH to prepare an alkaline solution; and the pH of the solution is 12.6 ~ 13.0. The chemical reagents used are all analytically pure.

B.6 Test procedures

B.6.1 Prepare the alkaline solution for test; fully soak test pieces.

B.6.2 Place test pieces in the thermostat soaking tank, with the distance between test pieces, between test pieces and the thermostat soaking tank, and between test pieces and the liquid surface, at least 10 mm. Maintain the temperature of the alkaline solution within (55 ± 3)°C.

B.6.3 Soak test pieces in the alkaline for 7 days. During the soaking process, stir the alkaline solution once every 12 h; use a pH meter for determination; record the pH of the liquid; and maintain the pH constant during test. The liquid and test pieces shall be kept in a dark place.

B.6.4 After soaking for 7 days, take out test pieces; use clear water to rinse the residual alkaline solution thoroughly on test pieces; wipe them dry and store for 7 days at room temperature; and carry out tensile property test for the soaked composite grids as required in Annex A.

B.7 Calculation

B.7.1 Load (stress)-strain curve

Load (stress)-strain curve is obtained using the date acquired by the data acquisition system.

B.7.2 Tensile strength retention rate

Calculate tensile strength retention rate in accordance with Formula B.1; take the […]