1 Scope
This standard specifies instruments, materials, mortar constituents, test conditions, operation procedures and result calculation for the reference test method of cement mortar strength. The measured results of compressive strength are identical to the results of ISO 679.Alternative standard sand and compaction table is listed. Any disagreement in the results after alternation is subject to the reference method.
This standard is applicable to the portland cement, ordinary portland cement, slag portland cement, portland fly-ash cement, compound portland cement, limestone portland cement, flexural strength and compressive strength inspection. When other cement adopts this standard, the applicability of this standard must be studied.
2 Normative References
The following standards contain provisions which, through reference in this text, constitute provisions of this standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the standards listed below.
GB/T 6003-1985 Test sieves
JC/T 681-1997 Mixer for mixing mortars
JC/T 682-1997 Jolting table for compacting mortars specimen
JC/T 683-1997 40mm x 40mm Jig for cement compressive strength test machine
JC/T 723-1982(1996) Apparatus for physical test of cement-mortar vibration compaction equipment
JC/T 724-1982(1996) Apparatus for physical test of cement-electrically driven flexure testing device
JC/T 726-1997 Mould for cement mortars
3 Principal Features of Method
The method comprises the determination of the compressive, and optionally the flexural, strength of prismatic test specimens 40 mm*40 mm*160 mm in size.
These specimens are cast from a batch of plastic mortar containing one part by mass of cement and three parts by mass of standard sand with a water/cement ratio of 0.5. Standard sands from various sources and countries may be used provided that they have been shown to give cement strength results which do not differ significantly from those obtained using the ISO Reference sand (see Chapter 11).
The mortar is prepared by mechanical mixing and is compacted in a mould using standard jolting apparatus, or the jolting apparatus with 0.75mm amplitude and 2800~3000 t/m frequency can be used (see Chapter 11).
The specimens in the mould are stored in a moist atmosphere for 24 h and then the demoulded specimens are stored under water until strength testing.
At the required age, the specimens are taken from their wet storage, broken in flexure into two halves and each half tested for strength in compression.
Foreword
ISO Foreword
1 Scope
2 Normative References
3 Principal Features of Method
4 Laboratory and Equipment
5 Mortar Constituents
6 Preparation of Mortar
7 Preparation of Test Specimens
8 Curing of Test Specimens
9 Test Procedure
10 Compliance Testing of Cement
11 Acceptance Testing of Sand and of Alternative Equipment
