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Preparation And Properties Of Cement Based Materials For 3D Printing Technology

Posted on:2018-10-19Degree:MasterType:Thesis
Country:ChinaCandidate:L XueFull Text:PDF
GTID:2321330563452355Subject:Materials engineering
Abstract/Summary:PDF Full Text Request
3D printing technology is a kind of rapid prototyping technology,which is based on the mathematical model,through the mechanical equipment will be printed material layer by layer.The technology is applied in different industries,in which the construction industry is in its infancy.3D printing technology has a great gap between the performance of cement based materials and the traditional forming process,and puts forward higher requirements for the performance of the material.At present,there is no systematic study on the performance requirements and evaluation methods of cement-based materials used in 3D printing technology.Therefore,it is imperative to study the cement based materials for 3D printing.The main properties of 3D cement based materials include: extrusion,constructability,printing time,mechanical properties and durability.This paper is mainly focused on the research of the performance before setting and hardening,and the selected materials are divided into two parts: the rheology adjusting component and the setting unit.The effects of various factors on the properties of cement based printing materials were studied,which were composed of temperature setting adhesive,hydroxypropyl methyl cellulose ether and latex powder.And put forward the test method of extrusion performance,stacking performance and bonding properties between layer and layer,explored the mortar slump,the fluidity and rheological property,the bleeding rate and extrusion properties and relations could be built directly.The influence of CQJSJ,the alkali liquid accelerator and the aluminum sulfate solution on the setting time,the slump and the early strength of the cement based printing material were studied.The results show that the hydroxypropyl methyl cellulose ether(HPMC)and Welan gum adhesive can effectively control the slump of cement mortar.Welan gum and hydroxypropyl methyl cellulose ether and redispersible powder could effectively reduce the bleeding phenomenon of cement-based materials,and could increase the bonding strength between the layers and the printing process,the bonding strength between the layers decreased with the increase of cement forming interval,initial bond strength before coagulation after the initial strength was greater than the coagulation,adding these three kinds of flow regulation group resulted in the loss of compressive strength.In the case of no bleeding,the cement base material doped Welan gum gel of slump in the range of 70-80 mm could be piled up best,adding amount of 0.35% for the viscosity of hydroxypropyl methyl cellulose ether 200 pa.s extrusion accumulation effect.The CQJSJ could control the initial setting time rang in 20-200 minutes,and could improve the early strength development of mortar.Alkali liquid accelerator could control the initial setting time rang in 3-130 minutes.With the addition of 10.0% CCQJSJ,the initial setting time was shortened to 2-19 minutes.It could increase compressive strength,and with the addition of 10.0% CCQJSJ,the strength were further increased,and the compressive strength of 3 hours was 1.0MPa.The initial setting time of the aluminum sulfate solution was controlled in 11-33 minutes,and the initial setting time of the 10.0% CCQJSJ was within 6-22 minutes.The early strength could also be improved with the aluminum sulfate solution,but the extrusion performance had some influence on.
Keywords/Search Tags:3D printing, cement based material, the rheological properties, the setting time, extrudability, buildability
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