Can we use crush sand in concrete
- Thread starter Suresh Raghvani
- Start date
Dnyan Deshmukh
Staff member
Where you want to use and what is purpose.
Please keep thread tittles and description in details, so that one can understand and reply to it
Please keep thread tittles and description in details, so that one can understand and reply to it
rameshchandrapatel
Active Member
Please refer Concrete Technology by MS Shetty. You can find your answers in Aggregate and its Properties chapter.
Dnyan Deshmukh
Staff member
Now a days due to environmental hazard by removing sand from river.
Every construction site uses crush rock sand, crush sand is produced in Vertical Shaft Impact Crusher(VSI) in same way how we get 20mm and 10mm size aggregates.
Practically the properties of aggregates does not affect the water / cement ration but it may affect the quantity of cement required for strength parameters.
more the surface area - more will be cement required to cover it and vice a versa.
more the material is finer or smaller in size - it will have more surface are.
Points to be ensured while purchasing crush sand
1. 150 micron cumulative percentage passing should be less than 15%.
2. sand should be preferable accepted as per Zone - I requirement.
The crush sand is better than river sand for using it in concrete.
there are many articles on forum which have detailed explanations on properties and usage etc.
Just do search on forum and you will get tons of information regarding same.
Every construction site uses crush rock sand, crush sand is produced in Vertical Shaft Impact Crusher(VSI) in same way how we get 20mm and 10mm size aggregates.
Practically the properties of aggregates does not affect the water / cement ration but it may affect the quantity of cement required for strength parameters.
more the surface area - more will be cement required to cover it and vice a versa.
more the material is finer or smaller in size - it will have more surface are.
Points to be ensured while purchasing crush sand
1. 150 micron cumulative percentage passing should be less than 15%.
2. sand should be preferable accepted as per Zone - I requirement.
The crush sand is better than river sand for using it in concrete.
there are many articles on forum which have detailed explanations on properties and usage etc.
Just do search on forum and you will get tons of information regarding same.
rameshchandrapatel
Active Member
Crushed Sand has now become a necessity for construction purpose. Central Government and State Governments have banned sand mining as they cause erosion of river banks which leads to floods in regions near it. RMC plants also use crushed sand.
shafi12344
Apprentice
If the Fineness modulus and specific gravity of the material comply the requirement we can use any material
Yes you can use a crushed aggregate sand for concrete, but you need to embark on a trial mix to check the effect on water demand and strength,since the dust con/fine content is higher with crushed stone sand, and of course you will need to increase your cement content to cope with increase surface area of materials.I recomend the blend of natural sand with the crushed stone sand.Another area of concern is the alkali silica reactivity.
HockeyPuck
Active Member
The use of manufactured sand in concrete production is very common - As our industry continues to move more towards environmentally friendly, recycled material sources, we as civil & materials engineers will need to continue to stay vigilant in testing the boundaries that new or recycled materials present.
With concrete, trial batch testing must always be carried out. Natural sands are used in concrete. Manufactured sands are used in concrete. Concrete mix design is both a science and and art that requires a great deal of practical and lab experience.
A word of caution: Sand properties will affect mix performance. Several years ago, one of our projects constructed slipformed concrete barrier along the median of an expressway. For weeks, we suffered with concrete that, for lack of a better term, was "ripping" as it was extruded from the machine.
The Contractor, the concrete supplier, our engineering crew as well as the Transportation Department searched for the causation of the problem for several weeks. Was it the machine? Was it the internal concrete vibration? Was it the speed the machine was placing the concrete? Was it the mix design? Some very intelligent engineering minds worked to solve the problem but to no avail. Adjustments were being tried day after day - Slump, air, machine speed, concrete admixtures - No one involved with the project had experienced anything like this before and we could not seem to find the solution....
After weeks of trying to make adjustments with some minimal positive effects, the concrete supplier tried changing the manufactured sand they were using to a natural sand: Guess what - Problem Solved!! We hypothesized that, on a micro-level, the particular cement & fly ash being used combined with the angularity of the manufactured sand being sourced were not providing the same type of water/cement interface as the natural sand and was causing the concrete mass to, essential, lose its internal stability. It was an ordeal that I hope to never have to experience again....
Lesson Learned - Never assume you have all the answers, particularly when it comes to material properties, as they can be inherently variable. As engineers, it is our job to always test our assumptions. Never be afraid to put your proposed concrete mixes through their paces, run tests, analyze the results and confirm that the material you plan to use will provide you with the performance criteria you desire.
With concrete, trial batch testing must always be carried out. Natural sands are used in concrete. Manufactured sands are used in concrete. Concrete mix design is both a science and and art that requires a great deal of practical and lab experience.
A word of caution: Sand properties will affect mix performance. Several years ago, one of our projects constructed slipformed concrete barrier along the median of an expressway. For weeks, we suffered with concrete that, for lack of a better term, was "ripping" as it was extruded from the machine.
The Contractor, the concrete supplier, our engineering crew as well as the Transportation Department searched for the causation of the problem for several weeks. Was it the machine? Was it the internal concrete vibration? Was it the speed the machine was placing the concrete? Was it the mix design? Some very intelligent engineering minds worked to solve the problem but to no avail. Adjustments were being tried day after day - Slump, air, machine speed, concrete admixtures - No one involved with the project had experienced anything like this before and we could not seem to find the solution....
After weeks of trying to make adjustments with some minimal positive effects, the concrete supplier tried changing the manufactured sand they were using to a natural sand: Guess what - Problem Solved!! We hypothesized that, on a micro-level, the particular cement & fly ash being used combined with the angularity of the manufactured sand being sourced were not providing the same type of water/cement interface as the natural sand and was causing the concrete mass to, essential, lose its internal stability. It was an ordeal that I hope to never have to experience again....
Lesson Learned - Never assume you have all the answers, particularly when it comes to material properties, as they can be inherently variable. As engineers, it is our job to always test our assumptions. Never be afraid to put your proposed concrete mixes through their paces, run tests, analyze the results and confirm that the material you plan to use will provide you with the performance criteria you desire.
Milind.P. kulkarni.
Newbie
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