Łątka Dawid
Faculty of Civil Engineering, Cracow University of Technology, Warszawska 24, 31-155 Kraków, Poland.
Materials (Basel). 2023 Mar 17;16(6):2402. doi: 10.3390/ma16062402.
The crucial task of the diagnosis of an existing masonry structure is to assess the current values of the mechanical parameters of the materials from which the structure was erected-usually bricks and mortar. The article presents the results of minor-destructive tests carried out on bed joints of three-brick-masonry prisms prepared in the laboratory. Three types of mortars used in the masonry were tested, which differ by the type and amount of binder. In order to determine mortar compression strength, three modern diagnostic methods were used: double punch test (DPT), standard penetrometric test (PT) and torque penetrometric test (TPT). Tests were carried out after 4, 12 and 90 weeks. The mortar strength determined in each of these tests was compared with the mortar reference strength determined on the beam specimen according to the methodology given in EN 1015-11. The results of the conducted tests confirmed the high usefulness of all three diagnostic methods. However, limitations in the application of the PT test were noticed-only lime mortars and weak cement-lime mortars can be tested with this method. In the case of mortars with an increased amount of cement binder, the impact energy is too low to estimate the compressive strength of the mortar in the brick wall joint. Technical limitations in the use of TPT and DPT tests were also indicated-weak lime mortars with low cohesion do not allow for obtaining reliable results. It was shown that DPT results strongly depend on two factors, specimen slenderness and mortar strength. Due to this fact, simple non-parameter conversion from mortar compressive strength according to the DPT test into mortar reference strength may lead to significant overestimation. As the results show, in newly built masonry, proper selection of diagnostic method is crucial due to the strong dependence of mortar curing dynamics on its location in the joint. This paper helps to match diagnostic techniques with the condition and type of mortar in the existing structure.
对现有砖石结构进行诊断的关键任务是评估建造该结构所用材料（通常是砖块和灰浆）的力学参数当前值。本文介绍了在实验室制备的三砖砌体棱柱体的水平灰缝上进行的微破损试验结果。对砌体中使用的三种类型的灰浆进行了测试，它们因粘结剂的类型和用量而有所不同。为了确定灰浆的抗压强度，使用了三种现代诊断方法：双冲试验（DPT）、标准贯入试验（PT）和扭矩贯入试验（TPT）。试验在4周、12周和90周后进行。将这些试验中确定的灰浆强度与根据EN 1015-11中给出的方法在梁试件上确定的灰浆参考强度进行了比较。所进行试验的结果证实了这三种诊断方法都具有很高的实用性。然而，注意到PT试验应用中的局限性——只有石灰砂浆和弱水泥石灰砂浆可以用这种方法进行测试。对于水泥粘结剂用量增加的灰浆，冲击能量过低，无法估计砖墙灰缝中灰浆的抗压强度。还指出了TPT和DPT试验使用中的技术局限性——内聚力低的弱石灰砂浆无法获得可靠结果。结果表明，DPT结果强烈依赖于两个因素，试件细长比和灰浆强度。由于这一事实，根据DPT试验从灰浆抗压强度简单地进行非参数转换为灰浆参考强度可能会导致显著高估。结果表明，在新建砌体中，由于灰浆固化动力学强烈依赖于其在灰缝中的位置，正确选择诊断方法至关重要。本文有助于使诊断技术与现有结构中灰浆的状况和类型相匹配。
