超高强水泥基灌浆材料力学性能尺寸效应

Size effect of mechanical properties of ultra-high strength cement-based grouting materials

超高强水泥基灌浆料具有大流态性、超高强、高弹模、高早强、抗疲劳性等性能,主要应用于海上风机基础灌浆连接结构部位。基于国内外检测标准,通过大量试验分析对比了超高强水泥基灌浆材料力学性能的尺寸效应。结果表明:超高强灌浆料抗压强度、静弹性模量、抗折强度以及劈拉强度等力学性能,因测试规范及试块尺寸差异,具有显著的尺寸效应;对于灌浆料抗压强度,立方体试块尺寸效应明显低于圆柱体试块,相较与基准组?准100×200 mm、Ф150×300 mm圆柱体试块换算系数仅为0.58和0.49;灌浆料抗折强度早期增长较快,7 d龄期已达到28 d龄期的87%,热养护制度下灌浆料抗折强度显著低于标准养护制度,高温环境产生热损失效应劣化灌浆料微观结构及力学性能,抗折强度衰减26.3%。依据国内相关标准,灌浆料静弹性模量测试值为55 GPa,而采用国外Ф100×200 mm圆柱体测试静弹模可增加10 GPa左右;超高强灌浆料无应变硬化现象,标准养护下早期劈拉强度迅速增,长1 d接近6 MPa、28 d后基本趋于稳定,相较劈拉强度,灌浆料轴心抗拉强度低于劈拉强度约7%,但试块制备要求较高,数据准确获取难度较大。

Ultra high strength ccment-based grouting material has the properties of large fluidity,super-high strength,high elastic modulus,high early strength and fatigue resistance,which is mainly used in the grouting connection structure of offshore fan foundation.The results show that the mechanical properties of ultra-high strength grouting material,such as compressive strength,static elastic modulus,flexural strength and splitting tensile strength,have significant size effect due to the test specifications and the size difference of test block.For the compressive strength of grouting material,the size effect of cube test block is significantly lower than that of cylinder test block,and the conversion coefficient ofФ100×200 mm andФ150×300 mm cylinder test block is only 0.58 and 0.49 compared with the reference group.The flexural strength of grouting materials increased rapidly in the early stage,and reached 87%of the 28 d age in the 7 d age.The flexural strength of grouting materials under the heat curing system was significantly lower than that under the standard curing system.The heat loss effect produced by high temperature environment deteriorated the microstructure and mechanical properties of grouting materials,and the flexural strength decreased by 26.3%.According to the relevant domestic standards,the test value of the static elastic modulus of grouting material is 55 GPa,while the test value of the static elastic modulus of foreign cylinder with diameter ofФ100×200 mm can increase about 10 GPa.The ultra-high strength grouting material has no strain hardening phenomenon,and the early splitting tensile strength increases rapidly under the standard curing,nearly 6 MPa for 1 d,and tends to be stable after 28 d.Compared with the splitting tensile strength,the axial tensile strength of the grouting material is about 7%lower than the splitting tensile strength,but the preparation requirements of the test block are high,and it is difficult to obtain the data accurately.