高海拔寒冷地区混凝土抗裂性试验研究

Experimental Study on Crack Resistance of Concrete in High Altitude Cold Area

为研究高海拔寒冷地区混凝土水化放热而导致的开裂问题,本文依托西藏某混凝土工程在现场制备了膨胀剂掺量分别为0%,8%,10%的3种高寒膨胀混凝土,通过平板抗裂试验观察了混凝土早期水化过程中的温度变化和开裂情况,力学试验记录了3d, 7d, 28d的抗压,抗折强度,得到不同膨胀剂掺量下高寒混凝土水化温度和力学性能变化规律,并对抗裂性能做出评价。结果表明:掺入膨胀剂可有效降低水化放热量,提高高寒混凝土的抗裂性能,膨胀剂掺量为8%和10%时抗裂性能升为Ⅲ级。同时,掺入膨胀剂高寒混凝土力学性能上升,且随着膨胀剂掺量增加呈先增后减的趋势,掺量为8%时强度较高。综合力学性能和抗裂性能,膨胀剂掺量为8%的高寒膨胀混凝土性能较好。

In order to study the cracking problem caused by the exothermic hydration of concrete in high altitude cold area,this paper relies on a concrete project in Tibet to prepare three kinds of alpine expansion concrete in the field with expansion agent dosage of 0%,8%and 10%respectively,and observes the temperature change and cracking in the process of concrete hydration in the early stage through the flat plate cracking test,and records the compressive and flexural strengths in the mechanical test of 3d,7d and 28d,and obtains the changing law of hydration temperature and mechanical property under different dosage of expansion agent,and evaluates the anti cracking property.The mechanical test recorded 3d,7d and 28d compressive and flexural strengths,and obtained the changing law of hydration temperature and mechanical properties of alpine concrete under different admixture of expansion agent,and evaluated the anti cracking performance.The results show that:the admixture of expansion agent can effectively reduce the hydration exotherm,improve the crack resistance of alpine concrete,expansion agent dosage of 8%and 10%of the crack resistance to rise to level III.At the same time,the mechanical properties of alpine concrete with expansion agent increased,and with the increase of expansion agent dosage showed a tendency of increasing and then decreasing,and the dosage of 8%was the highest strength.Comprehensive mechanical properties and anti cracking properties,expansion agent dosage of 8%of the alpine expansion concrete performance is the best.