Studi eksperimen variasi umur penyambungan beton lama dan beton baru pada balok ditinjau dari kuat lentur

Abstract

In reinforced concrete construction, beams are critical structural components designed to resist vertical and bending loads perpendicular to their axis. In field practice, the beam casting process is often constrained by factors such as weather and concrete delivery, necessitating staged casting with concrete joints connecting old and new concrete. This research investigated the flexural strength of staged-cast concrete beams joined with Sikacim Bonding Adhesive, evaluating the effectiveness of this material in bonding newly cast concrete to concrete that had already hardened at different ages. The study tested 3 normal beam specimens without joints and 9 jointed beams measuring 600 mm x 150 mm x 150 mm, with old concrete aged 3, 7, and 14 days. Beam bending tests were conducted at 28 days of concrete age, following SNI 4431–2011 standards. Results showed that normal beams achieved a bending strength of 3.396 MPa, while the bending strengths of beams joined at 3, 7, and 14 days were 1.652 MPa, 2.472 MPa, and 1.650 MPa, respectively, reflecting differences of -51.35%, -27.21%, and -51.41% compared to normal beams. These findings indicate that Sikacim Bonding Adhesive does not enable jointed beams to achieve or surpass the bending strength of normal beams, with the 7-day-old concrete joints showing the closest bending strength to that of beams without joints