GB/T 17671-2021 cement mortar strength test method (ISO method) Compared with GB/T17671-1999, in addition to structural adjustment and editorial changes, the main technical changes are as follows:

a) The scope has been changed to include the circumstances in which this document does not apply (see chapter 1, 1999 edition, chapter 1);

b) Substitute molding equipment and vibration table are written side-by-side (see 5.6.4.2,1999 version 11.7);

c) The requirements for compressive strength testing machines have been changed (see 5.6.6,1999 version 4.2.7);

d) The provisions of the Chinese ISO standard sand "single-stage sub-packaging" are deleted, and the storage requirements are increased (see 6.1.3. 1999 version 5.1.3);

e) The requirement for cement samples to be "evenly mixed before testing" has been added (see 6.2);

f) Changes to water requirements in the event of acceptance tests or disputes (see 6.3. 1999 version 5.3);

g) Changed molding and smoothing operations (see 8.2.1,1999 version 7.2.1);

h) The numbering method of the test was changed (see 8.2.1,1999 version 8.1);

i) Added the requirement to cover the die during maintenance (see 9.1);

j) Added the requirement that water change not exceed 50 per cent during maintenance (see 9.3);

k) Changes to the rules for breaking strength data (see 11.1.1. 10 from the 1999 edition.2.1);

l) Changed the rules for the rejection of compressive strength data (see 11.2.1. 10 from the 1999 edition.2.2);

m) The provision for accreditation of laboratories has been deleted，Added the acceptance test provisions;The method of overshoot processing of comparative test data is changed.Changed the acceptance method and procedure of China ISO standard sand;Added provisions for quality reporting and content of Chinese ISO standard sand and alternative molding equipment (see Chapter 12)，Chapter 11 of the 1999 edition)。

Recommended model

      2024欧洲杯买球Electronic compression and folding testing machine controlled by microcomputer。