Measurement of particle size distribution and specific surface area for crushed concrete aggregate fines

Abstract

Different methods for measuring particle size distribution (PSD) and specific surface area of crushed aggregate fines (≤ 250 µm), produced by high-speed vertical shaft impact (VSI) crushing of rock types from different quarries in Norway, have been investigated. Among all the methods studied, X-ray sedimentation is preferred because it has adequate resolution and requires fewer and more reliable input parameters. This combination makes it suitable for practical applications at hard rock quarries. X-ray microcomputed tomography (µCT) combined with spherical harmonic analysis was applied to estimate the actual error introduced when PSD measurements were used to calculate the specific surface area of the VSI crushed rock fines. The µCT results, to the limit of their resolution, show that the error in the calculated surface area caused by assuming spherical particles (a common assumption in PSD measurements) is of unexpectedly similar magnitude (-20 % to-30 %) over the entire investigated particle size range, which was approximately 3 µm to 200 µm. This finding is important, becauses it simplifies relative surface area determination and is thought to be quite general, since the crushed aggregate fines investigated were produced from 10 rock types that had a wide range of mineralogies.

Curcumin-Loaded Starch Micro/Nano Particles for Biomedical Application: The Effects of Preparation Parameters on Release Profile

“…This is due to the reduction effect of surfactant on particle size (Table ) which results in the specific surface area enlargement. As described elsewhere, considering two batches of the starch particles with different particle sizes but the same amounts, it is obvious that the number of the particles with smaller size is more than the number of the particles with larger size. Therefore, higher number of the particles would provide larger surface areas and thus more water penetration into the particles.…”

Research of the Operator’s Advisory System Based on Fuzzy Logic for Pelletizing Equipment

“…Continuously operating light [28,30] or strobe light [23,33] is used; • Sample pellets are illuminated from front [33,34] or from behind (backlight) [26,31,35]; • Pellet monolayer [23,30] or the pellet structure on conveyor or other surfaces is analysed [36][37][38][39][40][41]; and • Three-dimensional images [42,43] or complex data from hybrid (combining several measuring methods) systems are analysed [44].…”

Effects of Aggregate Micro Fines (AMF), Aluminum Sulfate and Polypropylene Fiber (PPF) on Properties of Machine-Made Sand Concrete

“…Compared to river sand, machine-made sand has several advantages, such as the existence of aggregate micro fines (AMF). There have been conflicting reports on the role of AMF [4][5][6][7] on the properties of machine-made sand concrete (MSC). Some researchers [8][9][10] reported a decreased slump and an increase in water demand in the MSC with an increase in AMF content.…”