Correlating Natural, Dry, and Saturated Ultrasonic Pulse Velocities with the Mechanical Properties of Rock for Various Sample Diameters

P-wave velocity is employed in various fields of engineering to estimate the mechanical properties of rock, as its measurement is reliable, convenient, rapid, nondestructive, and economical. The present study aimed to (i) correlate natural, dry, and saturated P-wave velocities with the mechanical properties of limestone and (ii) investigate how the ultrasonic P-wave velocities and mechanical properties of limestone are affected by the sample diameter. This study reveals that P-wave velocities under different environmental conditions can be correlated with the mechanical properties of limestone. Further, the R-value variations with different P-wave velocities for a given sample diameter are (i) negligible in terms of the uniaxial compressive strength (UCS) excluding 63.2 mm, (ii) limited for the diametrical point load index (PLID) except for 53.9 mm, (iii) perceived in case of the axial point load index (PLIA) for 47.7 mm, (iv) observed for the indirect tensile strength (ITS), but generally insignificant, and (v) detected in terms of Schmidt hammer value (SHV) except for 47.7 mm.

PENGARUH KADAR FLY ASH TERHADAP KUAT TEKAN PADAHIGH VOLUME FLY ASH-SELFCOMPACTING CONCRETE (HVFA-SCC) BENDA UJI D 15 CM X 30 CM USIA 28 HARI.

<p>Dalam upaya mengurangi efek <em>global warming </em>akibat limbah CO₂ hasil pembakaran semen ditelitilah <em>fly ash </em>sebagai bahan subtitusi semen. Kandungan senyawa silika ditambah alumina akan mengikat senyawa sisa hasil hidrasi semen (kalsium hidroksida,Ca(OH)₂) yang tidak mempunyai kemampuan mengikat, menjadi senyawa baru yang mempunyai sifat <em>cementitious</em> (mengikat) sehingga <strong>meningkatkan kekuatan beton yang dihasilkan. <em>Fly ash </em>juga memiliki sifat <em>ball bearing effect</em> yang meningkatkan <em>workability.</em></strong><strong><em> </em></strong><strong>Pada penelitian ini akan dianalisis </strong>pengaruh kadar <em>fly ash</em> terhadap kuat tekan yang dihasilkan masing masing kadar <em>High Volume Fly Ash Self Compacting Concrete (HVFA-SCC)</em> <em>Fly Ash</em> sebagai subtitusi semen pada <em>High Volume Fly Ash Self Compacting Concrete</em> (HVFA SCC) memiliki kadar mulai dari 50%. Pengujian beton dilakukan dengan sample diameter 15 cm x 30 cm pada 28 hari. Pada penelitian ini dibandingkan 3 variasi kadar <em>fly ash </em>yaitu 50%, 60%, 70% dan beton normal. Hasil penelitian menunjukkan kuat tekan HVFA-SCC semakin besar kadar <em>fly ash</em> semakin rendah kuat tekan yang dihasilkan. Kuat tekan yang dihasilkan untuk kadar <em>fly ash </em>50%, 60%, 70% dan beton normal adalah 60.58 MPa, 45.86 MPa, 38.21 MPa, 62.47 MPa.</p>