Випробування бетонних сумішей для 3D-друку з доступних матеріалів

Abstract

UA: У статті наведено результати розроблення бетонної суміші для технології 3D-друку з використанням доступних у Харківській області матеріалів. Основну увагу приділено забезпеченню необхідних реологічних характеристик, які допомагають транспортувати суміш трубопроводами, сприяють її екструдуванню та формостійкості. Проаналізовано вплив типу і дозування суперпластифікаторів, а також поліпропіленової фібри на показники рухомості, щільності, міцності на стиск і згин. Наведено результати механічних випробувань зразків, виготовлених із експериментальної суміші, і визначено масштабний коефіцієнт для оцінювання міцності на балочках порівняно зі стандартними кубами. Розроблену суміш випробувано для друкування на промисловому 3D-принтері ТОВ «Геополімер», що дало змогу виявити низку технологічних особливостей, пов’язаних із застосуванням фібри.

EN: The article presents the results of developing and testing a concrete mixture suitable for 3D-printing using locally available materials from the Kharkiv region of Ukraine. The research aimed to design a composition that meets the specific rheological and mechanical requirements of additive construction technologies while maintaining economic feasibility and material accessibility under regional market conditions. The study focuses on achieving optimal workability, extrusion stability, and structural integrity of the printed layers. Particular attention is given to the influence of superplasticizers and polypropylene fiber on the rheological behavior, density, and strength parameters of the concrete mixture. Experimental studies were conducted to determine the effect of different dosages and types of superplasticizers (C-3 and Master Silk) on flowability using a VZ-1 viscometer, which allowed the identification of an optimal content of 0.8 % for Master Silk without the need to increase the water-to-cement ratio. The role of polypropylene fiber with a length of 12 mm was also analyzed. It was found that the inclusion of 300–600 g/m³ of fiber provides the most stable compressive strength results (430–460 kgf/cm²) while maintaining adequate rheological properties. However, longer fibers caused technological complications during extrusion, such as fiber entanglement on the screw feeder, leading to periodic cleaning interruptions. Comprehensive mechanical tests were performed on beam (4×4×16 cm) and cube (10×10×10 cm) specimens to establish a scaling coefficient between different sample geometries. The obtained coefficient (0.9– 0.95) allows reliable correlation between laboratory and standard testing results. The developed mixture achieved a compressive strength exceeding 400 kgf/cm² and a flexural strength above 68 kgf/cm², corresponding to concrete class C25/30 with satisfactory frost resistance (F75) and water absorption below 4 %. The mixture exhibited a mobility grade of P8 with a cone penetration depth of 65±3 mm, ensuring compatibility with the extrusion mechanism of the industrial 3D-printer. Experimental 3D-printing was carried out on the industrial printer developed by LLC «Geopolymer», confirming the printability and structural integrity of the proposed composition. The study also revealed that even using readily available, unmodified local materials can yield high-performance concrete mixtures suitable for additive construction. Future research will focus on optimizing fiber geometry (2–6 mm) to improve print stability and minimize mechanical interference during extrusion. The developed mixture thus represents a cost-effective and technologically adaptable solution for 3D-printed construction in resource-constrained or war-affected regions.