scholarly journals Investigation on Comparison of Morphological Characteristics of Various Coarse Aggregates before and after Abrasion Test

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 492 ◽  
Author(s):  
Saisai Zhang ◽  
Jianzhong Pei ◽  
Rui Li ◽  
Yong Wen ◽  
Jiupeng Zhang
Keyword(s):  
Los Angeles ◽  
Surface Texture ◽  
High Performance ◽  
Morphological Characteristics ◽  
Repeated Loading ◽  
Abrasion Test ◽  
Coarse Aggregates ◽  
Los Angeles Abrasion ◽  
Before And After ◽  
Main Component

Under the repeated loading, the continuous impact and friction of tires on aggregates resulted in some changes in their morphology, which may cause rutting, decrease in skid resistance, and fatigue damage of the road. In order to explore specific changes in coarse aggregate morphology, the Los Angeles abrasion test was used to simulate the force exerted on coarse aggregates and the morphologies of different aggregates before and after abrasion were compared. Four types of coarse aggregates were selected and their mineral compositions were analyzed by X-Ray Diffraction (XRD). The morphological characteristics were measured using Aggregate Image Measurement System (AIMS-Ⅱ), including angularity, surface texture, sphericity and Flat and Elongation (F and E) ratio. Results showed that the angularity value for each type of aggregates significantly reduced after abrasion and the angularity reductions of various aggregates were consistent with the results of abrasion test, indicting the angularity reduction was the main component of abrasion loss. Whereas, there was no significant different between the surface texture of coarse aggregates before and after abrasion. For shape properties, both sphericity and F and E ratio results showed that aggregates with excessively high F and E ratio were easy to break, which might cause rutting and were harmful to pavement. Therefore, for pavements with high performance requirement, coarse aggregates with large angularity and low abrasion value should be preferred, whereas the quantity of particles with excessively high F and E ratio should be controlled.

scholarly journals Assessing the moisture susceptibility of aggregates with Los Angeles abrasion test

2017 ◽  
Author(s):  
Adelia Dwidarma Nataadmadja ◽  
Oki Setyandito ◽  
Eduardi Prahara ◽  
Ida Riyanti
Keyword(s):  
Los Angeles ◽  
Moisture Susceptibility ◽  
Abrasion Test ◽  
Los Angeles Abrasion

scholarly journals The effect of coarse aggregate hardness on the fracture toughness and compressive strength of concrete

2019 ◽  
Vol 258 ◽  
pp. 04011
Author(s):  
Atur P. N. Siregar ◽  
Emma L. Pasaribu ◽  
I Wayan Suarnita
Keyword(s):  
Fracture Toughness ◽  
Compressive Strength ◽  
Los Angeles ◽  
Coarse Aggregate ◽  
Concrete Aggregate ◽  
Beam Size ◽  
Intensity Factors ◽  
Coarse Aggregates ◽  
Los Angeles Abrasion ◽  
Compressive Strength Of Concrete

Coarse aggregate is the dominant constituent in concrete. Aggregate hardness is a variable needed to investigate in determining its effect on the critical stress intensity factors (KIC), dissipated fracture energy (Gf) and compressive strength (fc’) of the concrete. The hardness of coarse aggregate based on Los Angeles abrasion values of 16.7%., 22.6%, and 23.1% was used incorporated with Portland Composite Cement (PCC), and superplasticizer to create specimens. Cubes of 150x150x150 mm were employed to determine the fc’, and four beam sizes: 50x100x350 mm, 50x150x500 mm, 50x300x950 mm and 50x450x1250 mm were engaged to determine KIC and Gf. The fc’ and Gf of specimens manufactured by three different hardness of coarse aggregates were 45, 43, 40 MPa and 89.4, 54.0, 56.3 N/m respectively. KIC of specimens was 138.9, 119.4 and 114.1 MPa.mm1/2 for beam size of 50x100x350 mm; 148.2, 115.8 and 108.8 MPa.mm1/2 for beam size of 50x150x500 mm; 230.9, 183.1 and 157.9 MPa.mm1/2 for beam size of 50x300x950 mm; and 293.2, 248.1 and 244.3 MPa.mm1/2 for beam size of 50x450x1250 mm. Experimental results showed that decreasing hardness of coarse aggregate was found to have significant effect on the fracture toughness rather than on the compressive strength of concrete.

scholarly journals Weight loss of five commercially available denture teeth after toothbrushing with three different dentifrices

2006 ◽  
Vol 14 (4) ◽  
pp. 242-246 ◽  
Author(s):  
Karina Matthes de Freitas ◽  
Helena de Freitas Oliveira Paranhos
Keyword(s):  
Weight Loss ◽  
Abrasion Resistance ◽  
Acrylic Resin ◽  
Control Group ◽  
Distilled Water ◽  
Test Analysis ◽  
Abrasion Test ◽  
Before And After ◽  
Main Component ◽  
Artificial Teeth

Brushing is the most common cleansing method employed on complete dentures and it may damage the integrity of acrylic resin, the main component of this type of prosthesis. This study evaluated the abrasion resistance of artificial teeth with different number of acrylic layers, and the abrasiveness of specific and non-specific dentifrices for denture cleaning. The abrasion test was conducted by a tooth brushing device, using soft toothbrushes under load (200g). Sixty artificial teeth specimens were manufactured, 12 from each brand: Vipi-Dent Plus (Dental Vipi), Trubyte Biotone (Dentsply), Trilux (Ruthinium), Ivostar (Ivoclar) and SR Vivodent PE (Ivoclar). Three brands of dentifrices were selected: Colgate (Colgate-Palmolive), Bonyplus (Bonyf AG) and Dentu-Creme (Dentco). Distilled water was used as control. The brushing time was 100 minutes, at 356 strokes/minute. The specimens were weighed on an analytical balance before and after the abrasion test. Analysis of dentifrices' abrasive particles was made by scanning electron microscopy (SEM). Two-way ANOVA and Tukey tests were employed (alpha=0.05). The general mean of weight loss values were obtained: 6.1 mg (Ivostar); 6.0 mg (Trilux); 5.9 mg (Trubyte); 5.8 mg (Vipi); 5.3 mg (Vivodent). The abrasiveness difference among teeth brands was not statistically significant. The Colgate dentifrice produced the greatest weight reduction (10.1 mg), followed by Dentu-Creme (7.6 mg). Bonyplus was the least abrasive (2.4 mg), similar to the distilled water used as control group (3.1 mg) (p=0.05). It was concluded that all acrylic teeth presented similar abrasion resistance. Specific dentifrices for dentures tend to cause less damage to acrylic resin.

An approach to the abrasion testing of individual pieces of construction materials

1998 ◽  
Vol 13 (1) ◽  
pp. 193-196
Author(s):  
M. A. Eden
Keyword(s):  
Los Angeles ◽  
Abrasion Resistance ◽  
Construction Materials ◽  
Test Method ◽  
Test Material ◽  
Comparative Approach ◽  
Abrasion Test ◽  
Test Pieces ◽  
Los Angeles Abrasion ◽  
Abrasion Testing

AbstractThis paper briefly introduces the basis of abrasion testing and suggests a rapid and simple test that allows the abrasion resistance of specific materials to be evaluated. Small, individual pieces of rock, mortar, or concrete can be tested and the method has been used to evaluate the potential for surface abrasion of concrete surfaces. Many of the commonly used test methods for measuring abrasion resistance of construction materials are aggregate tests such as the QMW mill abrasion test and the ASTM Los Angeles abrasion test which measure the combined resistance of a material to impact and abrasion. Other tests such as the aggregate abrasion and polished stone value tests require a smaller numberof resin mounted aggregate pieces to be studied. The ASTM surface abrasion test for concrete uses physically large flat test pieces. Like the ASTM test, the test method described in this paper measures only the abrasion resistance. However, it provides a means of comparing the abrasion resistance of small pieces of construction material and introduces quartz as a reference material.The test uses a mixture of oil and carborundum as a grinding medium with 10 mm square test pieces held by a standard load against a rotating steel lapping wheel in a rotating jig. The results are expressed as a ratio of the abrasion rate of the test material to that of quartz tested in the same way. This comparative approach enables the test to be carried out using equipment of various designs.

scholarly journals Comparative Study of Physical and Mechanical Properties of Machine and Manually Crushed Brick Aggregate Concrete

2020 ◽  
Vol 8 ◽  
pp. 01-09
Author(s):  
Md Jahidul Islam ◽  
Jesika Rahman ◽  
Sadia Nawshin ◽  
Mohammad M. Islam
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Los Angeles ◽  
Physical And Mechanical Properties ◽  
Strength Properties ◽  
Technological Advancement ◽  
Coarse Aggregates ◽  
Los Angeles Abrasion ◽  
Crushed Aggregate ◽  
Crushed Brick

With technological advancement on the rise, manual crushing of bricks is gradually being replaced by machine crushing to obtain coarse aggregates for construction. However, properties of the brick aggregates obtained from these two methods vary which in turn, may affect the properties of the concrete matrix as well. This study represents a comparison between the machine crushed and manually crushed brick aggregates to be used as coarse aggregates in preparation of concrete. Four types of bricks, namely first class, second class, picket (over burnt) and ceramic were investigated, and each was crushed both manually and mechanically to a usable form of aggregates. The physical and mechanical properties of the brick aggregates derived from the two methods were tested and compared. In all types of brick, aggregates size, shape and strength properties such as flakiness and elongation indices, aggregate impact and crushing values and Los Angeles abrasion value showed lower values for manually crushed aggregate indicating better properties compare to machine crushed aggregates. This was evident while comparing compressive and tensile strength of concrete prepared with both manually and machine crushed first class and picket brick aggregates. Concrete with manually crushed brick aggregates showed marginally higher compressive and tensile strength in both types of brick aggregates.

Characterizing Ballast Degradation through Los Angeles Abrasion Test and Image Analysis

2014 ◽  
Vol 2448 (1) ◽  
pp. 142-151 ◽  
Author(s):  
Yu Qian ◽  
Huseyin Boler ◽  
Maziar Moaveni ◽  
Erol Tutumluer ◽  
Youssef M. A. Hashash ◽  
...  
Keyword(s):  
Image Analysis ◽  
Los Angeles ◽  
Abrasion Test ◽  
Los Angeles Abrasion
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