| The advancement of science and technology has promoted the innovation of architectural methods.Brand-new architectural methods and a wide range of application scenarios have placed higher demands on the design and technology of concrete materials.The development direction of concrete in the future will be converted into a concrete design centered on the overall system,introducing new elements from raw materials to processes,and preparing subversive concrete with new characteristics and new functions.Based on the innovation of concrete design method,this paper redesigned a new type of concrete structure from the source of concrete design and process.A new type of aggregate and skeleton structure are prepared after designed.After that,functional aggregate are designed and manufactured.Light-cured 3D printing technology is used to prepare bionic aggregates and skeletons with shapeable design,adjustable particle size gradation and versatility.The influence of 3D printed aggregates and skeleton on concrete is studied,including mechanical properties,elastoplasticity,interface properties,and microstructure.More importantly,composites which is the first of its kind are made using functionalized bionic aggregates and phase-change materials.Some properties of concrete that made by 3D printing phase-change aggregates are studied in this paper,including mechanical properties,early hydration,thermal insulation performance.The main conclusions obtained in this article are as follows:（1）The cured photosensitive resin which is made layer by layer has a dense structure and high toughness.Under different stress directions,the photosensitive resin showed higher strength and ultimate strain.When pressed,the maximum strain of photosensitive resin is 0.47,and the compressive strength can reach 131.04 MPa.When under tension,the ultimate strain is 0.42×10-2,and the tensile strength is 66.09 MPa.The durability of photosensitive resin in alkaline solution is pretty good while its ductility increases slightly after immersion.The compressive strength and ultimate strain fluctuated in a small range with the increase of immersion time,and reached 119.28MPa and 52.96×10-2 respectively after 28 days immersion.The tensile strength and ultimate strain can reach 50.52 MPa and 3.47×10-2,respectively.（2）The designed 3D printed aggregate and the tentacle-like bionic structure distributed on its surface have a good energy dissipation effect during the concrete destruction process.The specific strength of the bionic aggregate concrete is 16.18k N·m/kg,which is only 24.3%lower than that of basalt aggregate,and 48.6%higher than that of normal spherical aggregate.The compressive peak strain of the bionic aggregate concrete is 17.85×10-3,which is 283.0%greater than that of basalt aggregate concrete.The three-dimensional network skeleton structure also increased the compressive peak strain of concrete,which is twice that of basalt concrete.The 3D printed skeleton concrete showed the characteristics of multi-slit cracking when tensile,the ultimate tensile strength reached0.85MPa,and the ultimate strain was about 0.055.（3）3D printed phase-change aggregate has good mechanical properties,which makes the destruction of concrete ductile.The compressive strength reached 21.18MPa,the specific strength was 11.48k N·m/kg,and the compressive peak strain was increased by 239.3%compared to basalt concrete.The splitting tensile strength is 1.45MPa and the ultimate strain is 11.69×10-3,which is nearly 13 times that of basalt aggregate concrete.3D printed phase change aggregate concrete has better thermal properties.It can reduced the early peak temperature rise of concrete by 7.1%,and increased the maximum temperature difference between the inner and outer surfaces of the concrete slab during one-sided heating by 61.2%.In the meantime,3D printed phase-change aggregate concrete has better thermal insulation properties,which can effectively reduce the temperature difference inside the house when the ambient temperature changes.It has been reduced by 28.8%and47.8%in the two processes of heating and cooling,respectively.In summary,a digital design method for concrete aggregates is proposed in this paper.Several structures of aggregate and skeleton are designed and manufactured using photocuring 3D printing technology.The properties of 3D printed aggregate concrete,skeleton concrete,and phase change concrete are studied,which provides a new idea for the application of 3D printing in concrete and has a guiding significance for the design and development of concrete. |
