An experimental investigation on fracture parameters of self-compacting lightweight concrete containing magnetic water

This study describes an experimental research on the fracture parameters of self-compacting lightweight concrete (SCLC), which was mixed with tap and magnetic water (MW). Three-point bending tests were carried out on 90 notched beams with six mix compositions. The beams were made from mixes with three different water to cement (w/c) ratios of 0.37, 0.47 and 0.52; also, both tap and magnetic water were consumed in the concrete mixes separately. For all SCLC mixtures, common fracture parameters were specified by means of both work of fracture method (WFM) and the size effect method (SEM). The results of this research showed that by using MW in SCLC and decreasing w/c ratio from 0.52 to 0.37: (a) both initial fracture energy G_f and total fracture energy G_F increased, (b) the fracture toughness and the mechanical properties of SCLC improved. Additionally, the achieved data exhibited that there was a reasonable relation between the total fracture energy obtained by WFM and the initial fracture energy achieved through SEM. The average of G_F to G_f ratio in SCLC was 2.70. Furthermore, by using MW in SCLC mixtures, compressive strength, splitting tensile strength and modulus of elasticity increased up to 18%, 9% and 10%, respectively; also its self-compatibility in terms of fluidity increased about 5%.本研究针对掺加自来水与磁化水（magnetic water, MW）的自密实轻混凝土（self-compacting lightweight concrete, SCLC）的断裂参数开展试验研究。试验共设计6种配合比，制备90根带切口梁试件并开展三点弯曲试验；该6种配合比涵盖3组不同水灰比（water to cement, w/c），分别为0.37、0.47及0.52，且每组均分别采用自来水与磁化水拌制混凝土。针对所有SCLC配合比，分别采用断裂功法（work of fracture method, WFM）与尺寸效应法（size effect method, SEM）确定其常规断裂参数。研究结果表明，在SCLC中使用磁化水且将水灰比从0.52降至0.37时：(a) 初始断裂能G_f与总断裂能G_F均有所提升；(b) SCLC的断裂韧性与力学性能得到改善。此外，试验数据显示，采用断裂功法得到的总断裂能与通过尺寸效应法得到的初始断裂能之间存在合理的相关性；SCLC中G_F与G_f的平均比值为2.70。进一步而言，在SCLC配合比中使用磁化水时，其抗压强度、劈裂抗拉强度与弹性模量分别最高可提升18%、9%与10%；同时以流动度表征的自密实性能提升约5%。