Study On The Frost Resistance Of Concrete Under Axialcompressive Loading

High-strength concrete is rapidly developed, and being more and moreused in the project. However, the most widely used concrete in engineeringis medium and low strength concrete. How to improve the frost resistance,in order to extend the service life, is becoming one of the major facingproblems. While the frost resistance of concrete under sustained load is thekey to this question, according to this direction, a device is designed tomake concrete suffer the deterioration of sustained axial compressiveloading and freeze-thaw cycle.Via relative dynamic elastic modulus, flexural strength, compressivecapacity, the transverse relative dynamic elastic modulus, and thecumulative damage factor discussed in this research, the conclusions are asfollowing:1.By setting the different parameters (diameter, sizes,surface) of thereinforced in the concrete specimens to assess the effects on the frequencytest. The conclusion is that this influence can be ignored to someextent(6%). That’s what makes the specimen under sustained axialcompressive loading to freeze-thaw cycle deterioration own a base foundation.2. According to the air content, condensation time and the hardenedconcrete strength test in GB8076, an optimal dosage of Modified Camelliasaponins air entraining agent is determined as0.1‰.3. Taking the size effecting factor into the freeze-thaw cyclesdeterioration, an amendment was made on the freeze-thaw damage criteriafor the original《concrete long-term performance and durability testmethods standard》, and a new relative dynamic elastic modulus value iscorrected from0.6to0.75, which is used in this whole research.4. No matter it is ordinary concrete or air-entrained concrete, theinitial transverse relative dynamic elastic modulus of sustained axialcompressive loading specimens is much higher than no loading specimens,especially for the specimen under a stress/strength=0.25. Its downwardtrend of transverse relative dynamic elastic modulus is also significantlyfaster than the the specimens under load stress/strength=0,0.5.5. The transverse relative dynamic elastic modulus of ordinaryconcrete under a stress/strength=0.25is much sharper than thestress/strength=0,0.5. While the air-entrained concrete gives a gentledownward trend performance.6. The application of cumulative damage factor in the ordinaryconcrete and air-entrained concrete under sustained load is proved via thetrend of flexural strength, compressive capacity,...