The objective of this study is to examine the compressive strength and durability of very high-volume SCM concrete. The prepared 36 concrete specimens were classified into two groups according to their designed 28-day compressive strength. For the high-volume SCM, the FA level was fixed at a weight ratio of 0.4 and the GGBS level varied between the weight ratio of 0.3 and 0.5, which resulted in 70–90% replacement of OPC. To enhance the compressive strength of very high-volume SCM concrete at an early age, the unit water content was controlled to be less than 150 kg/m3, and a specially modified polycarboxylate-based water-reducing agent was added. Test results showed that as SCM ratio (R SCM) increased, the strength gain ratio at an early age relative to the 28-day strength tended to decrease, whereas that at a long-term age increased up to R SCM of 0.8, beyond which it decreased. In addition, the beneficial effect of SCMs on the freezing-and-thawing and chloride resistances of the concrete decreased at R SCM of 0.9. Hence, it is recommended that R SCM needs to be restricted to less than 0.8–0.85 in order to obtain a consistent positive influence on the compressive strength and durability of SCM concrete.
展开▼
机译:这项研究的目的是检查超大体积SCM混凝土的抗压强度和耐久性。根据设计的28天抗压强度,将准备好的36个混凝土试样分为两组。对于大批量的SCM,FA含量固定在0.4的重量比,而GGBS含量在0.3到0.5的重量比之间变化,这导致OPC的取代率为70-90%。为了提高超大体积SCM混凝土的早期抗压强度,将单位含水量控制在150 kg / m 3 sup>以下,并专门改性的聚羧酸盐基减水剂代理已添加。测试结果表明,随着SCM比(R SCM)的增加,早期强度相对于28天强度的强度增加率趋于降低,而长期年龄直至R SCM为0.8,则增加。它减少了。另外,在R SCM为0.9时,SCM对混凝土的抗冻融和抗氯化物的有益作用降低。因此,建议将R SCM限制在0.8-0.85以下,以对SCM混凝土的抗压强度和耐久性产生一致的积极影响。
展开▼