Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Study on the Properties of Different Coarse Aggregate Used in Concrete

M. S. Rahman
Associate Professor
Department of Farm Structure, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh

M. R. Karim
Graduate student
Department of Farm Structure, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh

M. Z. Rahman
Associate Professor
Department of Farm Structure, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh

A. K. Chosh
Associate Professor
Department of Computer Science and Mathematics, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh

Abstract/ Executive Summary:

A study was conducted to investigate some physical and mechanical properties like gradation and size, unit weight, moisture content, water absorption, specific gravity, abrasion loss, and strength of coarse aggregate used in concrete. Five different categories of coarse aggregate like gravels, stone chips, brick khoa, recycled stone chips and recycled brick khoa collected from different location of the country were selected for the study. The fineness modulus of the collected samples was 4.12, 4.47, 4.16, 5.14 and 4.54 respectively. Commonly available Portland composite cement and locally available river sand passing 4.75 mm sieve having fineness modulus 1.6 was used for preparing concrete cylinder prepared from different aggregate. The test result showed that the bulk unit weight for gravel, stone chips, brick khoa, recycled stone chips and recycled brick khoa was 1209.7, 1243.2, 840.0, 1041.6 and 873.7 kg/m³ respectively. The moisture content of the test samples was 0.93, 0.89, 1.78, 1.17 and 2.76% and water absorption was 1.89, 1.57, 12.29,3.23 and 11.26% respectively. The value of specific gravity was 2.52, 2.61, 2.07, 2.51 and 1.98 and the abrasion loss for the same was 16.8, 17.6, 26.4, 22.3 and 31.7% respectively. The compressive strength of concrete (1 :2:4) prepared gravel, stone chips, brick khoa, recycled stone chips and recycled brick khoa was 101.4, 98.3, 69.6, 91.8 and 65.0 kg/cm² and the tensile strength was 19.1, 18.9, 12.1, 17.3 and 11.2 kg/cm² respectively after 7 days water curing. Considering all the test results it is shown that, stone chips exhibits the best performance among all conventional coarse aggregate. Stone chips are better then brick khoa to be used as recycled aggregate in stead of conventional aggregate.

Keywords: Coarse aggregate used, concrete,

Location: Department of Farm Structure, Bangladesh Agricultural University, Mymensingh-2202, Bangladesh

Start Date:

End Date:

Program Area: Knowledge Management

Non-commodity: Adoption of technology

Objectives:

1. the physical properties of coarse aggregate such as unit weight, moisture content, water absorption and specific gravity

2. the mechanical properties of coarse aggregate such as abrasion loss and

3. the strength properties such as compressive strength and tensile strength of concrete prepared from these aggregates

Methodology:

The aggregate were tested for gradation and size, unit weight, moisture content, water absorption, specific gravity, abrasion loss, and compressive and tensile strength of concrete prepared from these aggregates. These tests were conducted in the Concrete and Materials Testing Laboratory of the Department of Farm structure at Bangladesh Agricultural University. The gradation of a particular aggregate was determined by sieve analysis according ASTM C136. The unit weight of the aggregate was obtained by measuring the weight of the aggregate divided by its volume following ASTM C29. Moisture content of the aggregates was obtained by oven dry method on dry basis. The water absorption is defined as the weight of water absorbed by the specimen and expressed as a percentage of the dry weight. The water absorption of the aggregates was determined by measuring the water absorbed by the aggregates after 24 hours immersed in water divided by the oven-dry weight of the aggregates. The specific gravity is an important parameter to determine void ratio and particle size. It was measured by determining the weight of aggregates divided by the weight of water displaced by the aggregate at specific temperature. Following the ASTM C535 test method abrasion loss of the aggregates was determined by Los Angles Abrasion Testing Machine and expressed as a percentage of the original weight of the aggregate. After seven days curing of concrete (1:2:4) cylinder prepared from different aggregates, compressive and tensile strength was determined. Compressive strength of concrete was tested by the Compression Testing Machine using the standard formula; compressive strength, 5_c = P / A, where P is the ultimate compressive load and A is the loading surface area of the concrete cylinder. For tensile strength, concrete specimen was placed with its axis horizontal between the plates of the Compression Testing Machine and the load was increased until failure by splitting along the vertical diameter took place. The tensile (51) strength was measured by following the equation; 5_t =2P /πLD, where P is the ultimate compressive load, L is the length of the concrete cylinder and D is the diameter of the concrete cylinder

Source of Information: Bangladesh Journal of Agricultural Engineering , Vol: 22 (1&2), PP: 45-52, 2011, ISSN: 1015-4426

Article Link (Online Journal):

Funding Source:

Budget:

Total Budget (Tk.) :

Achievement/Findings:

Grading or particle size distribution affects significantly on some characteristics of concrete like packing density, voids content, and consequently workability, segregation, durability etc. The unit weight of gravels and stone chips is greater than that of recycled stone chips. On the other hand, unit weight of recycled brick khoa is greater than that of conventional brick khoa. Water absorption is relatively high at conventional brick khoa than recycled one for high porous nature and the recycled brick khoa being covered with various binding materials. For recycled stone chips it is higher than gravels and stone chips due to cover of cement mortar paste on its outer surface that relatively absorb more water though their parent materials of gravels and stone chips are same. The abrasion loss of recycled aggregates is higher than conventional aggregates, because it is coated with cement mortar and the cement mortar paste is weaker and more prone to degradation than the conventional aggregate it is attached to. Based on strength stone chips are the best among all of the aggregates. The strength of conventional aggregate is higher than of recycled aggregate.

Knowledge Management: Journal