Mechanical Properties Of 3D Printed Concrete Permanent Formwork And Integrated Reinforced Concrete Components

The construction of reinforced concrete structures using traditional formwork is complicated,which requires long construction periods and high engineering costs.The non-recyclable use of traditional wood-based formwork causes a lot of resources’ waste and environmental pollution.In order to solve the above problems,various concrete permanent formworks were developed to replace the traditional wood formwork,aluminum formwork and glued formwork.However,these formworks have complicated manufacturing processes,which does not satisfy the requirements of reducing costs,saving resources and protecting the environment.Therefore,this paper used 3D printing technology to print permanent formwork with simple printing process and easy operation,which can realize the moldless manufacturing,achieving the requirement of sustainable development.As a part of the component,permanent formwork can combine the post-cast concrete into an integrity.Based on the 3D printing of permanent formwork,this paper mainly includes the following three parts: the bending performance of composite beam with permanent beam formwork and cast-in-place concrete,the shear performance of composite beam with permanent beam formwork and cast-in-place concrete,the axial compressive performance of composite column with permanent column formwork and cast-in-place concrete.(1)The bending behavior of composite beam with permanent formwork was experimentally tested.The test results show that the composite beam has the same failure mode as the integral cast-in-place beam with a same size,the cracking load of the composite beam is increased by 76.9% than that of the integral cast-in-place beam,and the crack development and crack width are limited by the permanent formwork.(2)The shear behavior of composite beam with permanent formwork was tested.The test results show that compared with integral cast-in-place beam,the crack load of the composite beam without web reinforcement is increased by 70.97%,and its ultimate load is increased by 18.2%;the cracking load of the composite beam with web reinforcement is increased by 78.2%,and its ultimate load is increased by 14.0%.To a certain extent,composite beam restrains the development of concrete cracks.The composite beam has a similar failure mode as the cast-in-place beam.(3)The axial compressive performance of composite column with permanent formwork was tested.The test results show that the carrying capacity of square composite column is 23.1% higher than that of cast-in-place column,and the carrying capacity of circular composite column is 36% higher than that of cast-in-place column.