Prediksi Kuat Tekan Beton Menggunakan Spesimen Kubus Berdasarkan Data Hammer Test - Partama, I Gusti Ngurah Eka (Civil Engineering Department, Universitas Muhammadiyah Yogyakarta, 2025)
Informasi kuat tekan pada saat pelaksanaan harus diketahui sedini mungkin untuk mengevaluasi mutu beton. Tuntutan hasil yang cepat dalam penentuan kuat tekan (f'ck) berbasis Compression Testing Machine sulit dipenuhi, apabila benda uji berada jauh dari laboratorium. Hammer Test yang dapat memprediksi kuat tekan dengan cepat untuk beton yang berumur minimal 14 hari perlu diadaptasi agar dapat digunakan untuk beton yang lebih muda. Penelitian bertujuan menganalisis hubungan nilai pantul Hammer Test untuk memprediksi f'ck pada benda uji kubus yang berumur kurang dari 14 hari. Data f'ck dan nilai pantulan palu (Rn) diambil berdasarkan 15 spesimen kubus 15x15x15cm3. Rn dan f'ck disusun berdasarkan uji tekan dan pantulan palu pada umur beton 3-28 hari. Rn diambil dari 16 titik pantul pada 3 sisi kubus dengan sumbu yang berbeda, kemudian Rn divariasikan dari rata-rata 16, 10, 8, 5, 4, dan 1 titik pantul. Korelasi yang paling tepat antara Rn dan f'ck ditentukan berdasarkan analisis regresi dengan faktor determinasi tertinggi (r²). Persamaan regresi tersebut, dikombinasikan dengan hasil eksperimen dan grafik ASTM serta penelitian dari 10 tahun terakhir, menunjukkan bahwa f'ck dapat diprediksi menggunakan Rn dari rata-rata 10 nilai pantul, α=-90° dari tiga sisi sumbu yang berbeda, dengan persamaan f'ck=2,449e0,0959Rn, r²=0,9997. Compressive strength information during implementation must be known as early as possible to evaluate the quality of concrete. The demand for fast results in determining compressive strength (f'ck) based on Compression Testing Machine is difficult to meet, if the test object is far from the laboratory. Hammer Test which can predict compressive strength quickly for concrete that is at least 14 days old needs to be adapted so that it can be used for younger concrete. This study was conducted using an experimental method that aims to adapt it so that it can be used to predict f'ck on cube test objects that are less than 14 days old. The f'ck data and hammer rebound values ​​(Rn) were taken based on 15 cube specimens of 15x15x15cm3. Rn and f'ck were compiled based on the hammer compression and rebound tests at the age of concrete 3-28 days. Rn was taken from 16 rebound points on 3 sides of the cube with different axes, then Rn was varied from an average of 16, 10, 8, 5, 4, and 1 rebound point. The most appropriate correlation between Rn and f'ck was determined based on a regression analysis with the highest determination factor (r²). This regression equation, combined with experimental results and ASTM graphs and research from the last 10 years, shows that f'ck can be predicted using Rn from the average of 10 reflectance values, α=90° from three different axis sides, with the equation f'ck=2.449e0.0959Rn, r²=0.9997