粗骨料含量对预拌成品超高性能混凝土抗压强度的影响

Effect of coarse aggregate on compressive strength of ready-mixed ultra-high performance concrete

为研究成品超高性能混凝土(UHPC)添加粗骨料后对其抗压强度的影响,以柳州欧维姆公司生产的袋装预拌成品超高性能混凝土为水泥基原料,通过添加2 cm内不同粒径和掺量的碎石,开展粗骨料含量对预拌成品UHPC抗压强度影响试验。研究表明:掺入筛分后碎石与掺入等量未筛分碎石的UHPC试块抗压强度相差不大,故可在实际应用中省去筛分过程,以提高生产效益;预拌成品UHPC试块抗压强度3 d/28 d均稳定在0.84~0.87之间,7 d/28 d均稳定在0.91~0.97之间,掺加粗骨料后的预拌成品UHPC可在短时间内形成较高且稳定的抗压强度值;当粗骨料含量为预拌成品UHPC质量的40%时抗压强度达到最大值,3、7、28 d强度分别为100.5、112.5、115.7 MPa;随着碎石掺量的增加,预拌成品UHPC抗压强度呈现先增大后减小的趋势,经济合理的掺量为40%。

In order to explore the effect of adding coarse aggregate on compressive strength of packaged ready-mixed ultra-high performance concrete,the packaged ready-mixed ultra-high performance concrete produced by Liuzhou OVM Machinery Co.,Ltd.was used as cement base,and the effect of coarse aggregate on compressive strength of finished UHPC was tested by adding gravel with different particle sizes and additives within 2 cm.The results show that there is little difference in the compressive strength of the test block mixed with the same amount of gravel and unscreened gravel,so the screening process can be omitted in practical application to improve production efficiency.The compressive strength of the ready-mixed UHPC test block 3 d/28 d is stable between 0.84 and 0.87,and the 7 d/28 d is stable between 0.91 and 0.97,and the ready-mixed UHPC with coarse aggregate could form a high and stable compressive strength value in a short time.When the content of coarse aggregate was 40%of the ready-mixed product UHPC,the compressive strength reached the maximum value,and the 3,7 and 28 d strengths were 100.5 MPa,112.5 MPa and 115.7 MPa,respectively.With the increase of the content of gravel,the compressive strength of the ready-mixed product UHPC first increased and then decreased.