Quality Testing of Sand at The Construction Site for The Concrete
There are different methods for testing the quality of sand at the construction site for concrete construction. The quality of the sand is as important as other materials for concrete.
The most different, which passes through the 4.75 mm IS strainer, is known as the fine aggregate. The fine aggregate will typically consist of natural sand, crushed stone sand, crushed gravel sand stone dust or arable powder, fly ash, and broken brick (burnt clay).
It will be hard, durable, chemically inert, clean and free from sedimentary coatings, organic materials, etc. and will not contain any appreciable amount of clay shells or pellets and harmful impurities.
To cause corrosion of iron pyrites, alkalis, salts, coal, asbestos, shale, or similar laminated or similar amounts of metal or to adversely affect the strength, durability, or presence of mortar, plaster or concrete.
The sum of the percentage of all harmful material shall not exceed 5%. Fine aggregates should be checked for biological impurities such as decayed vegetative humps, coal dust, etc.
Quality Test of Sand at a Construction Site
Following Are the Sand Tests at the Construction Site:
1. Testing of Organic Impurities
This test is done in the field for every 20 co or part thereof.
2. Silt Material Testing–
This is also a field test and is to be conducted for every 20 co.
3. Particle Size Distribution–
This test can be conducted on-site or in the laboratory for every 40 co sand.
4. Sandpile–
This test is conducted on-site for every 20 sand. Based on the bulking of the sand, the water-cement ratio suitable for concrete on site is calculated.
Types of Sand Test
1. Testing for Sand Silt Content Test
The maximum amount of silt in the sand shall not exceed 8%. Fine aggregates containing more than an acceptable percentage of silt will be washed so as to bring the silt content within an acceptable range.
2. Testing for Grading of Sand
On the basis of particle size, fine aggregates are classified into four regions. Where the grading is outside the range of a particular grading zone, the other strainer is over 600 microns.
If the total amount does not exceed 5 percent, it will be considered to fall within that grading zone.
3. Testing for Harmful Materials in the Sand
Such as seaweed or in such sufficient quantities as to adversely harden. To be positively affected. Specific strength or excellent durability of mortar.
The maximum amount of soil, fine silt, fine dust, and organic impurities in sand/marble dust shall not exceed the following limits:
(A) Clay, fine silt and fine dust when in IS 2386 (Part-II), natural sand or crushed gravel sand and crushed stone sand does not exceed 5% by mass.
(B) Organic impurities, when determined in the color of the liquid, will be the lighter according to IS 2386 Â than specified in the social code.
4. Testing for Sand Bulging
Dry aggregates, when dry or saturated, contain approximately the same amount but increase in income due to moisture. If the fine aggregate is moist in proportion to the ingredients of the mortar or concrete, its volume shall be suitably increased to allow in bulk.
Effect of Silt Penalty on the Durability Properties of Concrete
Silt fines are 75 smaller (number 200) particles smaller than the sieve. Typically, they are either silted or silted from clay and are difficult to remove from the overall surface.
Considering the high proportion of silt fines found in Taiwanese river sands, this research investigates the effect of the material on the properties of concrete.
In this study, solid samples with a w / c ratio of 0.48 and varying silt content ranging from 0% to 9% were separated and tested. In addition, chloride transport tests were performed to check the properties of concrete.
The test results indicate a decrease in durability when the ratio of silt content to fine aggregate is more than 5%.
The compressive strength, however, increases only 1 MPa when the silt volume is less than 5%. But it decreases from 3 MPa to 5 MPa when silt content increases from 7% to 9%.
These results can serve as a reference in concrete production, as well as quality control of fine aggregate with large quantities of silt fines.
Tests on Fine Aggregate
Dry aggregates, when dry or saturated, contain approximately the same amount but increase in income due to moisture.
If the fine aggregate is moist in proportion to the ingredients of the mortar or concrete, its volume shall be suitably increased to allow in bulk. At this time, there is no national specification regarding the use of desert sand with very fine grains.
Civil engineering has tested concrete made of Tengeli desert sand and masu sandy sand, to be able to apply desert sand to mortar and concrete and to clarify its engineering characteristics.
Typically based on the determined chemical composition and physical characteristics of desert sand, the mechanical properties of mortar, and modern concrete instantly made from two specific types of desert, sand was promptly investigated.
The results of the tests indicated that desert sand could be used as a good aggregate in mortar and concrete for general civil engineering.
Frequently Asked Questions (FAQ) about Sand Quality Testing for Concrete Construction:
Why is testing the quality of sand important for concrete construction?
Sand quality directly influences the strength, durability, and overall performance of concrete. Testing ensures that the sand meets necessary standards and is free from harmful impurities that could compromise the integrity of the concrete.
What are the main tests conducted to assess sand quality at a construction site?
The main tests include checking for organic impurities, silt content, particle size distribution, harmful materials, and bulking of sand. These tests help ensure that the sand meets specified criteria for use in concrete.
How is organic impurity testing conducted in the field?
Organic impurity testing is typically performed in the field for every 20 cubic feet of sand. It involves visually inspecting the sand for any organic materials, such as decayed vegetation or coal dust, which could adversely affect concrete quality.
What is the significance of silt content testing in sand?
Excessive silt content in sand can reduce concrete strength and durability. Testing ensures that the sand’s silt content does not exceed acceptable limits, typically 8%. If it does, the sand may need to be washed to remove excess silt.
How is grading of sand determined, and why is it important?
Grading of sand refers to the distribution of particle sizes within the sand. Proper grading ensures good workability and strength in concrete. Sand is classified into different grading zones based on particle size, and testing ensures that the sand falls within the specified zone.
What harmful materials are checked for in sand testing?
Sand is tested for various harmful materials such as clay, fine silt, fine dust, and organic impurities. These materials can adversely affect concrete properties and durability if present in excessive amounts.
How does silt content impact the durability properties of concrete?
High silt content in sand can decrease the durability of concrete, particularly when the silt content exceeds 5% of the fine aggregate. It may lead to reduced compressive strength and increased chloride transport, compromising the long-term performance of concrete structures.
Are there any considerations when using desert sand in concrete construction?
While there are no national specifications for desert sand, testing has shown that it can be used as a suitable aggregate in mortar and concrete for civil engineering projects. Mechanical properties and engineering characteristics of desert sand should be evaluated before use.
How can the findings of sand quality testing be applied in concrete production?
The results of sand quality testing can inform concrete production practices and quality control measures. By ensuring that only high-quality sand is used in concrete mixes, construction professionals can optimize the strength, durability, and performance of concrete structures.
