Investigation of the CoreLok for Maximum, Aggregate, and Bulk Specific Gravity Tests

Author(s):  
Gregory A. Sholar ◽  
Gale C. Page ◽  
James A. Musselman ◽  
Patrick B. Upshaw ◽  
Howard L. Moseley

The Florida Department of Transportation uses long-established test procedures to determine the maximum specific gravity (Gmm) and bulk specific gravity (Gmb) of asphalt mixtures and the bulk specific gravity (Gsb) of aggregates. The CoreLok, a vacuum-sealing device that can be used to determine these properties, was evaluated by the department for these test procedures. With respect to the Gmm test procedure, for mixtures containing nonabsorptive granites, the CoreLok determined results equivalent to those of the department's test procedure. However, for mixtures containing absorptive limestones, the CoreLok determined higher Gmm values than did the department's test procedure. The apparent reason for the discrepancy is that the CoreLok does not determine a saturated surface dry condition of the sample. With respect to the aggregate specific gravity test procedures, the CoreLok provided test results equivalent to the department's test procedure for the nonabsorptive fine aggregates only. For the absorptive fine aggregates and all of the coarse aggregates, the CoreLok determined Gsb test results significantly different from those of the department's test procedures. The CoreLok may be suitable for determining Gmb for coarse-graded compacted specimens with high porosity and air voids. There are concerns with the accuracy of the CoreLok results because of the bridging effect of the plastic bag over the large surface voids and because of the CoreLok's significant underestimation of the specific gravity of a solid aluminum cylinder.

Author(s):  
Harish Konduru ◽  
Prasad Rangaraju ◽  
Omar Amer

Alkali-silica reaction (ASR) is one of the most significant durability issues in concrete structures. Although there are a number of standardized test procedures to evaluate the aggregate reactivity, each method has its own drawbacks. Two of the most common tests that are employed widely are the accelerated mortar bar test (AMBT) (ASTM C1260) and the concrete prism test (CPT) (ASTM C1293). The major issue with the AMBT test is the number of false-positive results from this test associated with high test temperature, rendering the test method unreliable. CPT is one of the most reliable tests for assessing the potential for ASR, but its major disadvantage is the duration of the test involved, which takes one to two years. In this research, a novel test method called the miniature concrete prism test (MCPT) was developed and the effectiveness and reliability of the results assessed when compared with CPT and AMBT. Samples of 26 coarse aggregates and 16 fine aggregates with various reactivity levels were employed for the testing. The test results were compared for MCPT versus CPT, in which 23 out of 26 coarse aggregates and eight out of 16 fine aggregates either passed or failed in both MCPT and CPT. For MCPT versus AMBT, 16 out of 26 coarse aggregates and 13 out of 16 fine aggregates either passed or failed in both MCPT and AMBT. The sensitivity of false-negative and false-positive aggregate sources is discussed and explained briefly.


Author(s):  
Prithvi S. Kandhal ◽  
Rajib B. Mallick ◽  
Mike Huner

Bulk specific gravity of the fine aggregate is used in hot-mix asphalt volumetric-mix design (including Superpave) to determine the amount of asphalt binder absorbed by the aggregate and the percentage of voids in the mineral aggregate. The current test method (AASHTO T84) uses a cone method to establish the saturated surface dry (SSD) condition of the sample, which is necessary to conduct the test. This method does not work satisfactorily for fine aggregates that are very angular and have rough surface texture and, therefore, do not slump readily when in SSD condition. A research project was undertaken to develop automated equipment and a method of establishing the SSD condition of the fine aggregate. The wet sample of the fine aggregate is placed in a rotating drum and subjected to a steady flow of warm air. The temperature gradient of the incoming and outgoing air and the relative humidity of the outgoing air are monitored to establish the SSD condition. Two prototype devices were constructed. The test results obtained with the second prototype device are encouraging and are reported. Further improvements to be made to the second prototype device to improve the repeatability and reproducibility of the test have been identified.


2011 ◽  
Vol 374-377 ◽  
pp. 1623-1626
Author(s):  
Feng Jian Zhang ◽  
Guo Liang Bai ◽  
Zong Gang Quan ◽  
Long Pan

Recycled concrete hollow blocks are made with recycled fine aggregates and recycled coarse aggregates, so recycled block is a kind of green environmental material and can be used for masonry structure. Shear property is one main mechanical property of recycled concrete hollow block masonry. From the shear test of masonry, the shear strength has been researched. At the same time the rule calculated results and test results are compared and analyzed, conclude the design value of shear strength in this paper. The test results show that recycled concrete block masonry has better shear strength, so it can be used for wall material.


Author(s):  
S.E Ubi ◽  
P.O Nkra ◽  
R.B Agbor ◽  
D.E Ewa ◽  
M. Nuchal

This present research was on the comparison of the efficacious use of basalt and granite as coarse aggregates in concrete work. In order to obtain the basis for comparison, physical and structural tests were conducted on the different materials of the concrete and the concrete samples respectively. Physical test results revealed that basalt have a specific gravity of 2.8 and 2.5, while granite have a specific gravity of 2.9 and 2.6. In density, basalt have a density of 1554.55kg/m3 while granite had a density of 1463.64kg/m3. Aggregate impact test conducted on both aggregates revealed a percentage of 11.05% for basalt and 12.63% for granite. The following structural tests were carried out: compressive strength tests, flexural and tensile strength test and the comparative results are as follows. Compressive strength for basalt 36.39N/mm2 while 37.16N/mm2 for granite. 24.81N/mm2 tensile strength for basalt while 12.57N/mm2 for granite, 31.83N/mm2 flexural strength for basalt while 27.97N/mm2 for granite. From the above results, it can be deduced that basalt has higher strength properties than granite. Therefore, more suitable for coarse aggregate in achieving higher strength with some quantity of other composition of the concrete mix when compared to granite.


2020 ◽  
Vol XVII (3) ◽  
pp. 1-14
Author(s):  
Leila Shahryari ◽  
Maryam Nafisinia ◽  
Mohammad Hadi Fattahi

The effects of simultaneous use of recycled aggregates and ground blast furnace slag as a percentage of cement-constituting materials on different properties of fresh self-compacting concrete (SCC) are investigated in this study. To this end, three series of SCC mixtures with a fixed volume of cement paste equalling 380 ltr/m3 (2.36 gal/ft3) and the replacement ratio of coarse aggregates (fifty percent and one hundred percent) and total aggregates (zero percent, fifty percent and one hundred percent) were prepared. The water content ratios in the first, second and third series were 0.4, 0.45, and 0.5, respectively. The results of the compressive strength tests for 7-day, 14-day and 28-day cubic specimens and compressive strength and Brazilian test results for 28-day cylindrical specimens were used as control parameters governing the SCC resistive quality. The results of fresh SCC tests (including slump-flow and T50 tests, V-funnel test, and L-box test) showed that the negative effect of recycled fine aggregates on fresh SCC properties is significantly more than that of recycled coarse aggregate. However, recycled SCC with acceptable properties can be obtained with a slight increase in the amount of superplasticisers used in the presence of slag.


2015 ◽  
Vol 2503 (1) ◽  
pp. 110-118 ◽  
Author(s):  
Biagio Ciuffo ◽  
Alessandro Maratta ◽  
Monica Tutuianu ◽  
Konstantinos Anagnostopoulos ◽  
Georgios Fontaras ◽  
...  

To assess vehicle performance on criteria compounds, carbon dioxide emissions, and fuel energy consumption, laboratory tests are generally carried out. During these tests, a vehicle is driven on a chassis dynamometer (which simulates the resistances the vehicle encounters during its motion) to follow a predefined test cycle. In addition, all conditions for running a test must strictly adhere to a predefined test procedure. The procedure is necessary to ensure that all tests are carried out in a comparable way, following the requirements set by the relevant legislation. Test results are used to assess vehicle compliance with emissions limits or to evaluate the fuel consumption that will be communicated to customers. Every region in the world follows its own approach in carrying out these types of tests. The variations in approaches have resulted in a series of drawbacks for vehicle manufacturers and regulating authorities, leading to a plethora of different conditions and results. As a step toward the harmonization of the test procedures, the United Nations Economic Commission for Europe launched a project in 2009 for the development of a worldwide harmonized light-duty test procedure (WLTP), including a new test cycle. The objective of the study reported here was to provide a brief description of WLTP and outline the plausible pathway for its introduction in European legislation.


2019 ◽  
Vol 1 (6) ◽  
pp. 185-191
Author(s):  
Amirthagadeshwaran G ◽  
Ramesh S ◽  
Selvi K

Pervious concrete is a type of concrete with high porosity. It is used for concrete flatworks application that allows the water to pass through it, thereby reducing the runoff from a site and allowing ground water recharge. The high porosity is attained by highly interconnected voids content. Pervious concrete has water to cementicious material ratio of 0.36. The mixture is composed of cementicious materials, coarse aggregates and water with no fine aggregates. In this paper works porous concrete with fly ash as a blended material is tested for strength and permeability for assessing the adaptability of fly ash as a substitute material to cement. The percentage of fly ash is varied from 10% and 20%. Various tests like compressive strength, tensile strength and water permeability are done on the specimens and results are discussed.


Author(s):  
Cindy K. Estakhri ◽  
Joe W. Button

A Texas Department of Transportation study performed by the Texas Transportation Institute was undertaken with a goal of providing methods to assure the quality of cold-applied, asphalt-stabilized maintenance mixtures. Test procedures and acceptance criteria were developed for hot-mix, cold-laid asphalt concrete patching mixtures. Two specific objectives were to develop a test procedure to simulate approximately six months of stockpile-aging and a test procedure to quantify workability of maintenance mixtures. The protocol developed is designed to estimate the relative ability of a maintenance mixture to retain adequate workability after outdoor stockpile storage. This protocol could be useful as part of a specification to promote quality. Two test procedures were evaluated regarding their potential to quantify the workability of maintenance mixtures: a triaxial test and an unconfined compression test. Test results indicated that both procedures provide a relatively good measure of workability before and after aging. Two laboratory aging procedures were evaluated for their ability to predict workability of a stockpiled maintenance mixture after six months of field aging. Procedure A appeared to provide a reasonable approximation of six months of field aging.


2018 ◽  
Vol 3 (1) ◽  
pp. 55
Author(s):  
Suhendra Suhendra

Aggregate quality is very influential on the strength of the resulting concrete. Both coarse and fine aggregates have various characteristics identified from laboratory test results. This study aims to examine the use of various aggregates for a quality of concrete. The coarse aggregate and the fine aggregate used are obtained from the nearest location to the work to be performed. The quality of the concrete reviewed is K-125, K-175 and K-225. The coarse aggregates used are 1-2 size (in cm), 2-3 size (in cm) crushed aggregate and coral. The fine aggregates used for each of the coarse aggregates are also different. The results showed that the coral aggregate did not meet the gradations of concrete aggregate. While the fine aggregate does not meet the gradation of concrete aggregate for the three types used. The concrete compressive strength test results show the use of coarse aggregates of 2-3 size of crushed and coarse aggregate of corals giving the average compressive strength value required for all planned concrete strength. While concrete using coarse aggregates of rocks of size 1-2 only meet the specified compressive strength, but does not meet the required compressive strength.Key words: Aggregates, concrete, compressive strength


UKaRsT ◽  
2019 ◽  
Vol 3 (2) ◽  
pp. 52
Author(s):  
Nur Azizah Affandy ◽  
Agus Imam Bukhori

Concrete is a composite material (mixture) of several materials, whose main material consists of a mixture of cement, fine aggregates, coarse aggregates, water and or without other added ingredients coconut fibers are only used for broom materials, rugs, ropes and household appliances.Therefore, the addition of burning concrete into coconut ash ash is tried.The method used was experimental carried out in the laboratory with the production of 12 test pieces with presentations of 0%, 0.25%, 0.5% and 0.75% at 7 days.Laboratory test results on the addition of coconut fiber ash to the normal K 100 presentation were 16.505 MPa, coconut fiber ash mixture 0.25% reached 23.895 MPa, coconut fiber ash mixture 0.5% reached 23.656 MPa, the highest fiber ash mixture concrete 0.75% coconut can reach compressive strength of 23,688 MPa.


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