ASTM freeze-thaw

ASTM Freez -thaw (neat material 80 durability) 89.7/300 cycles... 

Fig. 3.1 The effect of 300 freeze-thaw cycles (according to ASTM C666 Procedure B) on air-entrained (right) and plain concrete (left).

This test followed ASTM C 1152-90 Standard Test Method for Acid-Soluble Chloride in Mortar and Concrete. The chloride content was investigated for the samples subjected to the deicing scaling test. Chloride measurements were taken after 25 freeze-thaw cycles. With an electric rotary-hammer powder samples were taken from concrete at four different depths 0 to 12mm, 12 to 25mm, 25 to 38mm, and 38 to 50mm. 

However, new AC174 (effective July 1, 2006, Section 5.1.1) says When compliance with SBC code requirements is desired, the following test loads in ASTM D 7032 shall be increased. The stated in-fill load in Section 6.2.2 of ASTM D 7032 shall be increased to 400 Ibf (1.78 KN), plus any adjustments required (temperature and moisture, UV light, and freeze-thaw effects). This means that, the load requirements were increased by at least 3.2 times. 

Section 4.7 Freeze-Thaw Resistance Test of ASTM D 7032 essentially repeats the above description from ASTM D 6662, with a couple of changes. First, not 15, but five specimens are required for the procedure of D 7032. Second, after completion... 

The beams, fabricated in the material testing laboratory, having dimensions of 7.5 cm x 7.5 cm X 30 cm were tested for relative dynamic modulus in accordance with ASTM C 666-97. Three-inch cubes were sawn from each of the beams after the relative dynamic modulus test. The cubes were tested using procedures presented in ASTM C 116-90, Test Method for Compressive Strength of Concrete Using Portions of Beams Broken in Flexure. When the specimens were 28 days old, the freeze-thaw durability specimens were cured in lime-saturated water until testing was begun. 

A work targeted specifically to civil infrastructure application has reported mechanical data on freeze-thaw tests conducted on isophthalic polyester and vinyl ester pultruded/glass fiber RPs (Chapter 3). Specimens were aged in accordance with ASTM C666 (namely, 40F to OF followed by a hold at OF and a ramp up to 40F followed by a hold) while submerged in 2% sodium chloride and water. Specimens were removed after every 50 cycles and tested in ASTM 3-point flexure mode. The results clearly indicated a reduction in flexure strength and modulus after 300 cycles. 

In this study, micro-structured polypropylene and glass fibers were both used sep>arately and in combination with macro-structured steel fibers in the concrete. Experiments were conducted in order to determine weight-loss and durability factor based on ultrasoimd pulse velocity of 12 different concrete series produced according to ASTM C-666. The separate and combined effects of the fibers used in the concrete in terms of the rapad freeze-thaw period were investigated. 

Freeze-thaw tests in the concrete series were conducted according to ASTM C 666 (Procedure B rapid freeze-thaw under air conditions). It was applied on standard prismatic specimens at the dimensions of 80x80x360 mm. The experiment was conducted after the specimens had been cured for 28 days. Heat transfer calculations were made in order to determine how long the heat in the specimens would take to reach the optimal heat required for the experiment so that the freeze-thaw test could be made in the deep frost according to ASTM C 666. Therefore, the central heat of the specimens (20 °C) was lowered to -20 °C. The central heat of the specimens left in the water was increased to 5.4 °C. 30 cycles were made altogether, with the central heat adjusted in such a way that it would vary between -20 °C (2 hours and 40 minutes) and 5.4 °C (36 minutes). 

This consists of the production of six cylindrical specimens and testing their indirect tensile strength according to ASTM D 4867 (2009) or AASHTO T 283 (2011). The specimens are compacted to 7% voids. One set of three specimens is partially saturated using a vacuum chamber, followed by optional freeze/thaw conditioning cycle and 24 h heating at 60°C. Then, all specimens are tested for determination of tensile strength. 

The evaluation of moisture susceptibility is carried out in the mixture with the optimum bitumen content and is determined by the tensile strength test carried out in accordance to ASTM D 4867 (2009) (AASHTO T 283 2011). However, the relevant modification to the specimen compaction (use 50 gyrations) and specimen conditioning (use of five freeze/thaw cycles), as stated in ASTM D 7064/D 7064M (2008), is applied. 

Standardized accelerated tests are useful for carrying out comparative tests of different composite materials. It is easier to determine which material is better than to forecast its effective durability. For example, it is believed that freeze-thaw tests as imposed by ASTM (2003) or other standardization institutions could ensure acceptable durability of cement-based materials in natural conditions during their lifetime in the climate of Northern America and Central Europe, even if the validity of simulation of natural conditions is doubtful. The possibility of using accelerated tests for glass-fibre-reinforced composites are discussed in Chapter 4. 

Freeze/thaw stability (cycles to fail), ASTM D 2243 >5 1... 

Petrographic examination. Petrographic examination is a microscopic analysis of concrete, performed on core samples removed from the structure. Further details may be foimd in the ASTM C856 standard. It yields information such as the depth of carbonation, density of the cement paste, air content, freeze-thaw damage, and direct attack of the concrete. 

The superior resistance to a vari ety of degrad i ng effects was reported by Bonneau etal. [59] for RPC freeze-thaw-durability factor equal or greater than 1 scaling-cumulative mass of scaling residue less than 0.03 kg/m (compared with a maximum of 0.80 kg/m allowed in the standards) chloride permeability (ASTM Cl 202) - less than 10 Coulomb (from a practical point of view this is impermeable concrete a range of 500-1000 Coulomb is considered as high performance concrete). The permeability under load conditions, in which cracks are induced, was evaluated by Charron et ai [60] showing that at strains of up to 0.13% the permeability was as low as that of the matrix. This is an indication of the durability potential of such composites under load. 

ASTM C666-97 Standard test method for resistance of concrete to rapid freezing and thawing. ASTM Book of Standards Volume 04.02, 2001. 

ASTM C666 freezing and thawing in water, was the test used. 

ASTM C 666-71, Resistance of Concrete to Rapid Freezing and Thawing, Part 10 (1973). 

ASTM D 560. 2003. Standard test methods for freezing and thawing compacted soil-cement mixtures (Withdrawn 2012). West Conshohocken, PA ASTM International. 

ASTM C 666/C666M -03 (2003) Standard Test Method for Resistance of Concrete to Rapid Freezing and Thawing , Annual Book of ASTM Standards 2004, 04(02), ASTM International. 

---