Experimental Study of Mechanical Properties of 3D Printing Bricks with Construction Spoil During Extrusion

Abstract:

In this paper， the printability of 13 kinds of engineering spoil with different mix proportion in extrusion process was studied. Meanwhile， unconfined compressive strength test and direct shear test were carried out for spoil samples mixed with river sand and recycled powder respectively， and the feasibility of river sand and recycled powder as engineering spoil admixture was discussed. The experimental results show that the mixing proportion of clayey spoil will affect the extrusion effect of composite spoil. When the mixing proportion of clay reaches 50%， the extrusion effect is good. The addition of recycled powder can improve the unconfined compressive strength and elastic modulus of spoil. Beyond this range， the super water absorption of recycled powder will seriously affect the cohesion of spoil， resulting in the decrease of strength and the maintenance time of elastic deformation stage. On the premise of ensuring the strength improvement and extrudability of engineering spoil， it is suggested that the content of recycled powder is 5%， and the unconfined compressive strength of spoil can be increased by 22.5%， while the incorporation of river sand will reduce the unconfined compressive strength and elastic modulus of spoil as a whole， showing an inverse skeleton effect. In terms of reducing environmental pollution and promoting intelligent earth building， 3D printing extrusion technology is used to produce engineering 3D printing bricks that meet different requirements， which has high application value and potential.

Key words:construction spoil;bricks;3D printing;extrudability;unconfined compressive strength