Kubica Jan, Galman Iwona
Department of Structural Engineering, Silesian University of Technology, 44-100 Gliwice, Poland.
Materials (Basel). 2023 Mar 8;16(6):2171. doi: 10.3390/ma16062171.
In the present study, experimental investigations on the influence of mixing water content used for the preparation of mortar mix using factory-made dry-mix mortar dedicated to bricklaying with clinker masonry units are presented, as well as the curing time on flexural bond strength of masonry made of these two materials. The flexural bond strength was tested using the "wrench test" method. The masonry tests specimens were prepared using three volumes of mixing water as follows: 4.0 L (the value recommended by the mortar manufacturer); 4.5 L; and 5 L of tap water per one 25 kg bag of dry pre-mixed mortar. The influence of the mixing water content was analyzed in relation to curing time. All masonry specimens were tested in four series after 9, 14, 21, and 28 days of sample curing. The results showed that the use of 6 and 18% more mixing water than recommended by the manufacturer (4.5 and 5 L per bag) adversely affected flexural bond strength. Moreover, for all three mixing water amounts, it was found that the maximum values of bonding strength were reached after 9 days of curing, which decreased over time. The largest decreases (30-40%) were recorded after 14 days. After 21 days, these values continued to decrease, but more slowly. The final value of the ratio of bond strength to flexural strength of the mortar was similar for all amounts of mixing water and for the 28-day curing time, it oscillated around 0.2.
在本研究中，展示了关于使用工厂生产的用于与烧结砖砌体单元砌筑的干混砂浆制备砂浆混合物时的拌合水含量，以及养护时间对由这两种材料制成的砌体的弯曲粘结强度的影响的试验研究。弯曲粘结强度采用“扳手试验”方法进行测试。砌体试验试件按照每25千克袋装干混砂浆使用三档拌合水量制备：4.0升（砂浆制造商推荐的值）；4.5升；以及5升自来水。分析了拌合水含量相对于养护时间的影响。所有砌体试件在样品养护9天、14天、21天和28天后分四个系列进行测试。结果表明，使用比制造商推荐量多6%和18%的拌合水（每袋4.5升和5升）会对弯曲粘结强度产生不利影响。此外，对于所有三档拌合水量，发现粘结强度的最大值在养护9天后达到，随后随时间下降。在14天后记录到最大降幅（30 - 40%）。21天后，这些值继续下降，但速度较慢。对于所有拌合水量以及28天养护时间，砂浆粘结强度与弯曲强度之比的最终值相似，在0.2左右波动。
