4.1. The strength of concrete for compression should be determined in accordance with GOST 10180 on a series of samples made of a concrete mixture of working composition and stored under conditions specified in GOST 18105.
When testing foundation blocks with non-destructive methods, the actual yield strength of concrete for compression should be determined by ultrasonic method in accordance with GOST 17624 or mechanical action devices in accordance with GOST 22690, as well as other methods provided for by standards for concrete testing methods.
(Changed edition, Amendment No. 1).
4.2. (Excluded, Amend No. 1).
4.3. Concrete grade for frost resistance should be determined in accordance with GOST 10060.
4.4. Water resistance of concrete foundation blocks should be determined in accordance with GOST 12730.0 and GOST 12730.5 on a series of samples made of a concrete mixture of working composition.
(Changed edition, Amendment No. 1).
4.4.1. (Excluded, Amend No. 1).
4.5. Water absorption of concrete foundation blocks intended for use in conditions of exposure to corrosive environments should be determined in accordance with the requirements of GOST 12730.0 and GOST 12730.3 on a series of samples made of a concrete mixture of working composition.
(Changed edition, Amendment No. 1).
4.6. (Excluded, Amend No. 1).
4.7. The moisture content of lightweight concrete should be determined according to GOST 12730.0 and GOST 12730.2 by testing samples taken from finished foundation blocks.
From each unit should be selected at least two samples.
It is allowed to determine the moisture content of concrete foundation blocks using the dielectric method in accordance with GOST 21718.
(Changed edition, Amendment No. 1).
4.8. The dimensions and deviations from the straightness of the foundation blocks, the position of the mounting loops, the width of the opening of the technological cracks, the dimensions of the shells, the inroads and the concrete blocks of the foundation blocks should be checked by the methods established in GOST 26433.0 and GOST 26433.1.
(Changed edition, Amendment No. 1).