Adhesion Between Concrete and Treated or Untreated Flat Metal Surfaces

Abstract

Modern construction techniques for floor and slab systems often make use of the composite action developed between steel and concrete. Knowledge of the magnitude of adhesive force, other than mechanical bond, is necessary in the design of permanent steel formwork, which ultimately becomes an integral part of the load bearing reinforced concrete structure. To investigate the extent of adhesion at the interface between concrete and flat metal surfaces, different treatments of the metal surfaces were considered. Results are presented for six types of treated and untreated metal plates when tested in a pull-off mode with conventional concrete. The mode and the type of failures were investigated, and those parameters, which are considered to be significant in the study of this phenomenon, evaluated

On functional signatures of bare and coated formwork skin surfaces

“…This layer formed in the skin asperities is an aqueous solution composed of the fine particles contained in the cement-filler mixture. The subsequent physicochemical interactions and mechanical anchoring of the concrete to the skin [2]- [6] cause the formation of many aesthetic defaults such as discoloration, micro-bulling, and concrete breaking [1] [3] that are visible on the surface of concrete walls after formwork removal operations. The required restoration operations are unfortunately costly and timeconsuming and are unnecessary if a weak negligible skin-concrete adhesion is achievable.…”

“…The adhesion of the concrete on the skin may possibly arise from electrical bonding [4] [5] and chemical bonding through the Ca(OH) 2 formation [4]- [6]. The interfacial bonding depends partly on the water-cement ratio [7], the polymer additives [5] [7] [8] and the filler substitutes [7].…”

“…Few works have investigated the effect of the skin superficial characteristics with the concrete ability to adhere to the skin. The adhesion is avoidable with a controlled skin roughness that is low enough to avoid mechanical anchoring and high enough to avoid capillary forces [2]- [5] or with a controlled skin chemistry using a special galvanized superficial treatment [6]. The wear resistance to the concrete abrasion is reduced by smoothing the surface [14].…”

An experimental study on adhesion between steel and cement pastes using particle probe scanning force microscopy

“…Enamel coated steel and concrete exhibited higher pull‐out strength than ordinary steel . Another experiment used to measure the steel‐cement adhesion is the pull‐off test . Steel and cement bulks are bonded over a flat surface, and tensile force is applied to pull them away from each other.…”

“…Khalaf and Page performed pull‐off tests to measure the bond strength between steel and cement mortars with various mixes and surface properties. Similar methods have been used by Montgomery and Samarin to study the bond strength between treated and untreated metal surfaces and cement. In addition to the two mechanical tests aforementioned, Zhang et al used the Brazilian nut disks to evaluate the bonding between steel and cement/mud system.…”