Standard No.:	GB 751-1981
Chinese Name:	水泥胶砂干缩试验方法
English Name:	Test method for drying shrinkage of cement mortar
Professional Classification:	GB National Standard
Issued by:
Issued on:	1981-10-01
Implemented on:	1981-10-01
Status:	VALID
Language:	English
File Format:	PDF
Word Count:	2500 words
Price(USD):	180 (USD)
Delivery:	via email in 1 business day

This standard is applicable to the comparison of drying shrinkage performance of different cements.

The drying shrinkage of cement mortar measured in this standard is determined by measuring the length change of 1:2.5 plastic mortar specimen of 25×25×280mm (both ends are equipped with spherical nail head) with comparator after the specimen is cured in dry air.

When the specimen used for determination of drying shrinkage performance is placed in dry air, the temperature is 20±3℃ and the relative humidity is 60±5%. The temperature and humidity shall be checked and recorded every day.

I. Instruments

1. Mortar mixer

See the requirements of GB 177-77 Test method for strength of cement mortar, clause 1, article 1.

2. Shock table, truncated-cone round mold and mold sleeve, cylindrical tamper and caliper, which shall all meet the requirements of GB 2419-81 Test method for fluidity of cement mortar, clause 1.