试验方法对砖的干燥收缩的影响试验研究

Experimental Study on the Effect of Test Methods on Drying Shrinkage of Bricks

非烧结砌体干燥收缩导致墙体开裂,试验方法不同使测得的干燥收缩值相差很大.通过试验研究了温度、通风条件和干燥剂对试验环境相对湿度的影响,并分4组进行共40个混凝土砖的干燥收缩对比试验,研究了不同干燥收缩试验方法对砖的总干燥收缩的影响.试验表明,温度越高,相对湿度越小,试件干燥速度越快,干燥收缩越大.GB/T2542、GB/T4111和ASTM-C426方法测得的总干燥收缩值比BS/EN772-14测得的大28.6%,比AS/NZS 4456.12测得的小27.2%.建议取块体干燥收缩值的50%作为砌体结构设计规范的干燥收缩值.

Drying shr inkage of non sintered br ick masonry causes wall cracking and different test methods make the measured value of drying shrinkage vary greatly. The effects of temperature, ventilat ion conditions and desiccant on the relat ive humidi ty of the test environment were tested and the effects of test methods on the total drying shrinkage of brick were studied by 4 groups of 40 drying shrinkage specimen of concrete brick. The results showed that the higher the temperature, the lower the relat ive humidi ty, the faster the drying rate, the bigger the drying shr inkage. The total drying shrinkage measured by GB/T2542SGB/T4111 and ASTM-C426 method was 28. 6% larger than that of BS/EN 772-14, and 27. 2 % smaller than that of AS/NZS 4456. 12. The drying shrinkage value of the Chinese design code of masonry st ructure was sugges-ted to be 50% of the dry shrinkage value of the brick.