Pull-out behaviour of threaded anchors in fibre reinforced ordinary concrete and UHPC for machine tool constructions

Kalthoff, Matthias; Raupach, Michael

doi:10.1016/j.jobe.2020.101842

Cited by 9 publications

(5 citation statements)

References 20 publications

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“…The high temperatures results in the additional activation of silica fume. The same effect could also be observed, e.g., in [ 1 ]. The comparison of Series 12 and 13 also shows that subsequent water storage after initial heat curing at 105 °C results in a decrease in compressive strength.…”

Section: Resultssupporting

confidence: 80%

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Influence of High Temperature Curing and Surface Humidity on the Tensile Strength of UHPC

2021

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The objective of this study is an investigation of the different parameters that influence the tensile strength of ultra-high performance concrete (UHPC). Apart from the shrinkage and stiff-ness, the tensile strength is an important parameter for the design of crack-free concrete elements, e.g., in machine tool construction. One focus of our work is the influence of concrete curing and the great impact of the mechanical and physical characteristics of hydrated UHPC. For this reason, different curing regimes were investigated. The results show that even after heat treatment or autoclaving, the centric tensile strength of UHPC specimens is strongly influenced by the surrounding ambient humidity. Test specimens that were stored under water after a heat treatment or autoclaving and were still wet during the test had the highest tensile strengths. Storage at 20 °C and 65% relative humidity (rH), however, results in a 25% reduction in tensile strength. Alternating storage between water storage at 20 °C water and storage at 65% rH can also reduce the tensile strength dramatically by up to 70%. In particular, samples that were stored at 65% rH right before testing had very low tensile strengths. Surprisingly, the initially low tensile strength of previously dry stored UHPC can be restored by subsequent water storage. In the absence of any microstructural defects, e.g., microcracks, a possible explanation for this phenomenon can be the stress differences due to a humidity gradient between the core and surfaces and shrinkage combined with a continued reaction of the unhydrated binders of the UHPC.

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Section: Resultssupporting

confidence: 80%

“…The main objective of this work was the development of a suitable concrete composition that meets the high technical requirements of machine tool constructions [ 1 , 2 ]. During the use of machine tools, a drop in stiffness or even cracks in the construction has to be prevented.…”

Section: Introductionmentioning

confidence: 99%

Influence of High Temperature Curing and Surface Humidity on the Tensile Strength of UHPC

2021

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“…Fibre 1 represents a type of steel fibre that is commonly used in Europe for SFRC. In contrast, fibre 3 is recommended for use in UHPC, as presented in [ 67 ]. Fibre 2 was chosen due to its geometry, which is directly in between those of the other fibres.…”

Section: Methodsmentioning

confidence: 99%

Electrical Resistivity of Steel Fibre-Reinforced Concrete—Influencing Parameters

2021

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This paper presents a systematic study of the electrical resistivity of different steel fibre-reinforced concretes with fibre contents from 0 kg/m3 to 80 kg/m3 in order to identify possible effects of interactions among concrete composition and fibre type and content regarding electrical resistivity. Based on a literature review, four parameters, w/c ratio, binder content, ground granulated blast-furnace slag (GGBS) and fineness of cement, which show a significant influence on the electrical resistivity of plain concrete, were identified, and their influence on the electrical resistivity as well as interaction effects were investigated. The results of the experiments highlight that the addition of fibres leads to a significant decrease in electrical resistivity, independent of all additional parameters of the concrete composition. Additionally, it was shown that a higher porosity of the concrete, e.g., due to a higher w/c ratio, also results in a lower electrical resistivity. These results are in agreement with the literature review on plain concrete, while the influence of the concrete composition on the electrical resistivity is weaker with the increase in fibre content. The influence of fibre reinforcement is thus not affected by changes in the concrete composition. In general, a higher fibre dosage leads to a decrease in electrical resistivity, but the impact on the electrical resistivity varies slightly with different types of steel fibres. Based on this study, the potential of determining the fibre content using electrical resistivity measurements could be clearly presented.

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“…Threaded anchors can be broadly categorized into three main types based on their anchoring mechanisms: mechanical interlock, friction, and bond. These mechanisms play a crucial role in transferring loads to the surrounding construction [9,10,11,12,13]. In the case of mechanical interlock, the connection between the bolt head element and the adjacent concrete establishes a strong interlocking mechanism.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

Study On Interface Fracture And Failure Modes In Steel Plate And Concrete Embedment

Selva Ganesa Moorthi,

Appa Rao

2023

Proceedings of the 11th International Conference on Fracture Mechanics of Concrete and Concrete Structures

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Interface between connecting steel plates and concrete plays an important role on performance of precast reinforced concrete shear wall system. Embedded steel plate provides dry connection with prefabricated panels as bolted or welded plate connection via anchoring rods or bolts during fabrication process. Recently, prefabricated techniques gained momentum due to time and material savings, enhanced quality control and increased efficiency with sustainability. Connection in precast system alters failure mode of the entire system by improving damage resistance. This paper describes the pull-out bond tests performed on a steel plate embedded in concrete using three distinct methods of anchoring to analyze behavior of steel plate-concrete embedment under tension loading. The test specimen consists of steel plates embedded in concrete blocks with three different anchoring schemes by a) rod, b) bolt and c) bolt with washer nut arrangement as anchorage and different number of bolts. The steel plates were connected to a loading frame through bolts and nut system, and then transferred the load to the plate to measure the slip with reference to concrete surface. The loaddisplacement response of the connection has been monitored, and the failure modes were examined. The test results have been compared with the existing analytical model to determine the pull-out bond behaviour and influence of number of bolts and the concrete strength. Anchoring using bolt and washer nut system performed better than the other anchoring methods.

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Pull-out behaviour of threaded anchors in fibre reinforced ordinary concrete and UHPC for machine tool constructions

Cited by 9 publications

References 20 publications

Influence of High Temperature Curing and Surface Humidity on the Tensile Strength of UHPC

Influence of High Temperature Curing and Surface Humidity on the Tensile Strength of UHPC

Electrical Resistivity of Steel Fibre-Reinforced Concrete—Influencing Parameters

Study On Interface Fracture And Failure Modes In Steel Plate And Concrete Embedment

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