Bonding performance of steel plate aerated concrete blocks with different adhesive areas

A reinforced concrete subsoil granary has been the promising type in agricultural production in recent years. Among them, a steel plate is used as the waterproof layer, which is connected to the reinforced concrete silo wall by welded bolts on the contact side of the steel plate and the reinforced concrete silo wall. The moisture-proof layer is taken as the aerated concrete blocks using epoxy structural adhesive. Specially, the aerated concrete block is bonded to the steel plate, thus forming a structural layer of epoxy structural adhesive bonding the steel plate and aerated concrete block. This study aims to evaluate the safety and reliability of this structural layer under the horizontal lateral pressure and friction of grain. The results are as follows: 1) Once the adhesive area was the same, there was the increase in the deformation, ultimate bearing capacity and bond strength at the interface of steel plate aerated concrete block under horizontal-vertical bidirectional loading, compared with the vertical unidirectional loading. The better bonding performance was then achieved under the horizontal lateral pressure that generated by the grain storage in the silo; 2) The damage pattern of vertical unidirectional loading was obtained, where the aerated concrete blocks were peeled off from the epoxy structural adhesive; In horizontal-vertical bidirectional loading, a penetrating crack was formed in the aerated concrete blocks, and then the whole block moved downward under the horizontal load, but without peeling off. A comparison was made on the damage patterns of vertical unidirectional loading and horizontal-vertical bi-directional loading. Therefore, it was beneficial to the stabilization of the interface, in the case of aerated concrete blocks under vertical loading while applied horizontal lateral pressure. 3) The bond strength was closely related to the friction force on the silo wall, when the adhesive area was A, 0.8A, 0.5A (A was the contact area between a single aerated concrete block and a steel plate). Once the adhesive area was 0.5A, the smallest height of grain storage was achieved under the vertical unidirectional loading, indicating the larger than the actual height. Therefore, the structural layer with the gluing area of 0.5A was fully met the requirements of the bearing capacity and bonding strength under grain storage loads in the design of underground granaries. 4) It was feasible to adopt the construction practice of epoxy structural adhesive bonding steel plates and aerated concrete blocks for underground granaries under the horizontal lateral pressure and vertical friction of grain. 5) The bearing capacity and bond strength were fully met the requirements, when the bonding area of epoxy structural adhesive exceeded 50% of the total area of aerated concrete block. Further consideration should be given to the influence of the epoxy structural adhesive thickness and application mode on the displacement, bearing capacity, bond strength and damage pattern of the structural layer. The findings can provide a strong reference for the safety and reliability of the waterproof and moisture-proof structural layer in the new underground granary.