Kajian Perilaku Mekanik Kuat Lentur Out-of-Plane Dinding 3D Concrete Printing dengan Berbagai Pendekatan

Fitriandy Noor Prasangka, Prof. Ir. Iman Satyarno, M.E., Ph.D., IPU.; Ir. Suprapto Siswosukarto, Ph.D. IPM.

2026 | Tesis | S2 Teknik Sipil

Teknologi 3D Concrete Printing (3DCP) berkembang sebagai metode konstruksi inovatif yang memungkinkan proses pencetakan beton secara berlapis tanpa menggunakan bekisting. Keberhasilan penerapan teknologi ini sangat dipengaruhi oleh kemampuan mortar dalam memenuhi persyaratan printability, extrudability, dan buildability, serta memiliki sifat mekanik yang memadai. Penelitian ini bertujuan mengembangkan mortar 3DCP berbasis semen Portland Composite Cement (PCC) dengan penambahan silica fume, superplasticizer, viscosity modifying agent (VMA), dan serat polypropylene, serta mengevaluasi pengaruh metode perkuatan berupa tulangan baja, seismic coating, dan kombinasi keduanya terhadap perilaku mekanik elemen hasil cetak.

Karakteristik mortar segar dievaluasi menggunakan flow table test mengacu pada ASTM C1437, sedangkan sifat mekanik dianalisis melalui pengujian kuat tekan, modulus elastisitas, dan pengujian lentur empat titik (four-point bending test) pada umur 28 hari. Evaluasi dilakukan terhadap mortar dasar (BL), mortar dengan serat polypropylene (BLPP), mortar dengan tulangan baja (BLT), mortar dengan seismic coating (BLCT), serta kombinasi serat polypropylene dan tulangan baja (BLPPT) untuk menilai pengaruh variasi material dan metode perkuatan terhadap kinerja elemen 3DCP.

Hasil penelitian menunjukkan bahwa mortar yang dikembangkan memiliki kemampuan printability, extrudability, dan buildability yang baik dengan nilai flow sebesar 196,74–199,53 mm, tanpa mengalami segregasi maupun bleeding. Penambahan serat polypropylene meningkatkan nilai flow sebesar 2,79% serta membantu menjaga stabilitas lapisan selama proses pencetakan. Mortar BL menghasilkan kuat tekan efektif rata-rata sebesar 18,86 MPa dengan modulus elastisitas sebesar 15.505,03–16.886,39 MPa, yang menunjukkan kekakuan material yang baik. Pada pengujian lentur, BL memiliki kapasitas beban maksimum tertinggi sebesar 12,10 kN, namun mengalami keruntuhan getas. Penambahan tulangan baja mampu mempertahankan integritas elemen setelah retak awal, sedangkan seismic coating memberikan pengendalian retak paling efektif dengan lendutan terkecil sebesar 2,03 mm. Serat polypropylene berkontribusi melalui mekanisme crack bridging, sementara kombinasi perkuatan menghasilkan respons pasca-retak yang lebih stabil meskipun belum meningkatkan kapasitas lentur secara signifikan akibat keterbatasan ikatan mortar–tulangan. Pola keruntuhan didominasi oleh retak tarik lentur, disertai retak antarlapisan dan spalling lokal yang mencerminkan karakteristik anisotropi material 3DCP.

3D Concrete Printing (3DCP) has emerged as an innovative construction technology that enables automated layer-by-layer concrete fabrication without the need for conventional formwork. However, its successful implementation depends on the development of mortar that satisfies the requirements of printability, extrudability, and buildability while providing adequate mechanical performance. This study aimed to develop a PCC cement-based mortar incorporating silica fume, superplasticizer, viscosity-modifying agent (VMA), and polypropylene fibers, and to evaluate the effects of reinforcement strategies, including steel reinforcement, seismic coating, and their combination, on the mechanical behavior of 3D-printed elements.

Fresh mortar properties were evaluated using the flow table test in accordance with ASTM C1437, while hardened properties were assessed through 28-day compressive strength, modulus of elasticity, and four-point bending tests. The experimental program included the base mortar (BL), polypropylene fiber-reinforced mortar (BLPP), steel-reinforced mortar (BLT), seismic coating-reinforced mortar (BLCT), and the combined polypropylene fiber and steel reinforcement system (BLPPT) to investigate the influence of material modification and reinforcement methods on the performance of 3DCP elements.

The results demonstrated that the developed mortar exhibited excellent printability, extrudability, and buildability, with flow values ranging from 196.74 to 199.53 mm without segregation or bleeding. The incorporation of polypropylene fibers increased the flow value by 2.79% and improved layer stability during printing. The BL mixture achieved an average effective compressive strength of 18.86 MPa and a modulus of elasticity ranging from 15,505.03 to 16,886.39 MPa, indicating adequate stiffness and load-bearing capacity. Flexural testing showed that BL achieved the highest maximum load capacity (12.10 kN) but exhibited brittle failure. Steel reinforcement improved the post-cracking integrity of the printed elements, whereas seismic coating provided the most effective crack control, resulting in the lowest deflection (2.03 mm). Polypropylene fibers enhanced crack resistance through the crack-bridging mechanism, while the combined reinforcement system produced a more stable post-cracking response despite limited improvement in flexural capacity due to insufficient mortar–steel bond strength. Failure was predominantly characterized by flexural tensile cracking accompanied by interlayer cracking and localized spalling, reflecting the anisotropic behavior of 3D-printed mortar.

Kata Kunci : 3D Concrete Printing, mortar, polypropylene fiber, seismic coating, steel reinforcement, flexural strength.