Effect of multilayer casting technology of self-compacting concrete slabs on the load-bearing capacity of a layer-to-layer joint

Dybeł, Piotr; Kucharska, Milena

doi:10.1016/j.jobe.2022.105655

Cited by 1 publication

(2 citation statements)

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“…Additionally, it was found that applying a second layer with a thickness significantly exceeding that recommended [100 mm] (15) was not adequate to achieve a shear effect between the two layers during a delay time of 60 minutes. Considering both the outcomes of this research and findings in the literature (13,14,16,17), the recommendation is to place successive layers of SCC mix in beam and wall elements with a thickness of ≥100 mm, allowing a delay of up to 30 minutes.…”

Section: Recommendationsmentioning

confidence: 99%

“…Studies conducted on the multilayer placing of slab elements have identified three factors contributing to a decrease in the load-bearing capacity of the joint between successive layers. These are as follows: the delay time, the distance from the mix casting point, and the first layer preparation technology (13). The most significant decrease in joint strength was identified in the technological variant where the mix freely flowed over the already placed layer.…”

Section: Introductionmentioning

confidence: 99%

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Effect of self-compacting concrete placement technology on the load-bearing capacity of the concrete-concrete and steel-concrete bond in layered elements

Dybeł

2023

Cement Wapno Beton

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The article presents a study on the technology of layered execution in self-compacting concrete structures. The research focused on 800×480×160 mm panel elements, cast in two layers from a single mix casting point. Three different delay times for delivering the second layer of mix were considered: 15, 30 and 60 minutes. Two technological variants of mix application were analysed: from the top and from the bottom of the mould. The study investigated the influence of the placement technology on the load bearing capacity of the concrete layer-to-layer joint and the rebar-to-concrete joint. The load-bearing capacity of the concrete layer-to-layer joint was determined through a splitting tensile strength test on core specimens extracted from panel elements. Notably, existing literature has primarily explored the load-bearing capacity of the concrete layer-to-layer joint on smaller elements and has not accounted for mix placing technologies diverging from the traditional one. A test of the rebar-to-concrete bond at the layer interface was conducted using the pull-out method. Substantial differences were identified in the mixing pattern of concrete layers, contingent on the placing technology employed. Top-down casting led to a reduction in the load-bearing capacity of the concrete layer-to-layer interface, coupled with decreased stiffness and bond strength of the rebar-to-concrete connection as the delay time of the second layer increased. Conversely, bottom-up concreting maintained the load-bearing capacity of the combined concrete layers at 90% of the strength of the monolithic specimen throughout the entire test range. The article recommends the utilization of bottom-up placing technology for executing elements in the multilayer casting of self-compacting concrete.

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Section: Recommendationsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%