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What is the fineness range of cement?
Fasi Ur Rahman
As per Indian Standard, the cement particle more than 10% shall not retain on the sieve (90 µm). The detailed test to determine the fineness of cement is given in the article linked below- Fineness Modulus of Cement by Dry Sieving
As per Indian Standard, the cement particle more than 10% shall not retain on the sieve (90 µm).
The detailed test to determine the fineness of cement is given in the article linked below-
See lessFineness Modulus of Cement by Dry Sieving
What is polymer concrete?
Fasi Ur Rahman
Polymer cement concrete is a composite concrete that consists of synthetic polymer within the binding material. Polymer concrete has advantages of higher properties, low energy requirements, and low labor costs. It is also called Polymer Portland cement concrete (PPCC) or latex-modified concrete (LMRead more
Polymer cement concrete is a composite concrete that consists of synthetic polymer within the binding material. Polymer concrete has advantages of higher properties, low energy requirements, and low labor costs. It is also called Polymer Portland cement concrete (PPCC) or latex-modified concrete (LMC).
Read more on polymer concrete-
Polymer Cement Concrete: Properties and Uses
See lessConcrete strength results
Fasi Ur Rahman
Answer- Without knowing the ultimate strength of the concrete mix, the results obtained on the 7th day can not be declared as right or wrong. Considering the results obtained on the 7th day, i.e, 8.137 N/mm2, the designed strength of the concrete mix shall be M12. The results obtained on the 7th dayRead more
Answer-
- Without knowing the ultimate strength of the concrete mix, the results obtained on the 7th day can not be declared as right or wrong.
- Considering the results obtained on the 7th day, i.e, 8.137 N/mm2, the designed strength of the concrete mix shall be M12.
- The results obtained on the 7th day must be 66% of the ultimate strength. So the ultimate strength of the concrete for the mix that can be expected on 28th day shall be 12 N/mm2.
See lessExplain the operating principle of the rebound hammer?
Fasi Ur Rahman
The rebound hammer test method is based on the principle that the rebound of an elastic mass depends on the hardness of the concrete surface against which the mass strikes. The operation of the rebound hammer is shown in figure-1. When the plunger of the rebound hammer is pressed against the concretRead more
The rebound hammer test method is based on the principle that the rebound of an elastic mass depends on the hardness of the concrete surface against which the mass strikes. The operation of the rebound hammer is shown in figure-1. When the plunger of the rebound hammer is pressed against the concrete surface, the spring-controlled mass in the hammer rebounds. The amount of rebound of the mass depends on the hardness of the concrete surface.
Thus, the hardness of concrete and rebound hammer reading can be correlated with the compressive strength of concrete. The rebound value is read off along a graduated scale and is designated as the rebound number or rebound index. The compressive strength can be read directly from the graph provided on the hammer’s body.
For more details on principle, procedure, advantages & disadvantages of rebound hammer test, kindly check the article below-
Rebound Hammer Test on Concrete – Principle, Procedure, Advantages & Disadvantages
See lessWhat is the effect on strength of concrete if an RMC transit mixer is halted for 3 hours?
Fasi Ur Rahman
The first thing we need to know is the amount of retarder used for the preparation of concrete. Generally, the concrete starts to harden after 30mins of adding water into it. By the use of a retarder, the setting time of the concrete is delayed. Generally, for RMC mix concrete the setting time startRead more
The first thing we need to know is the amount of retarder used for the preparation of concrete. Generally, the concrete starts to harden after 30mins of adding water into it.
See lessBy the use of a retarder, the setting time of the concrete is delayed. Generally, for RMC mix concrete the setting time starts after 4hrs.
Thus, in your case, there shall be no effect on the strength of concrete.
But it is advised to check the slump of the concrete before pouring.
How to add Nanosilica to concrete?
desvl
Colloidal Nanosilica is supplied in liquid form so it should be added to concrete during mixing as any liquid would be added ideally through a dispenser but can be measured out and added with a bucket by simply pouring it into the mix and ensuring it is thoroughly mixed .
Colloidal Nanosilica is supplied in liquid form so it should be added to concrete during mixing as any liquid would be added ideally through a dispenser but can be measured out and added with a bucket by simply pouring it into the mix and ensuring it is thoroughly mixed .
See lessWhy is the risk of efflorescence formation in cement-based materials high in coastal areas?
aviratdhodare
Efflorescence is layer of salts left behind by an evaporating sol'n of salts on masonry surfaces. It is quite usual on plastered walls, ceilings, concrete, cement plastering, and painted walls. Why and how does it occur? It occurs when the dissolved salts in cement, sand, and water in constructionsRead more
Efflorescence is layer of salts left behind by an evaporating sol’n of salts on masonry surfaces. It is quite usual on plastered walls, ceilings, concrete, cement plastering, and painted walls.
Why and how does it occur? It occurs when the dissolved salts in cement, sand, and water in constructions are brought to the surface through leaching. In the second stage, the water evaporates to the atmosphere leaving powdery crystalline salts on the surface.
These salts could be present in cement due to breakdown and aging.
The sand used is of inferior quality containing salts. Though river sands are used in construction, excessive quarrying could lead to poorer quality. Instead of using sand from river or lake beds, adulteration with seashore sand could be the cause.
Water used for curing is impure with dissolved salts in it. Saline water with dissolved salts could turn out to be the culprit.
At the initial stages, the formation of a salt layer on the surface could go unnoticed. However repetitive cycles of evaporation and leaching steadily build-up the salt and the seriousness of the problem is visual. In some cases, growth in fungi could be noticed accompanied by efflorescence leading to unhygienic spaces.
Let us turn our attention to the question of the acceleration of corrosion near the seashores. Galvanic corrosion is the type of corrosion noticed near seashores. Salt in the form of aerosols reaches places located 30 KM inshore.
Salt, water, and the wind are the players that accelerate the corrosion process. Near the seashores, all these prime ingredients are readily available.
See lessWhat are the additives or aggregates needed for 3D printed Concrete?
aviratdhodare
Any material will give you a finished form if it’s the right consistency and is deposited using an effective method. Guessing, I would say industrial grout with sand and latex additive. The project budget, scale and environment will dictate the material formulas and extruder specifications, which arRead more
Any material will give you a finished form if it’s the right consistency and is deposited using an effective method. Guessing, I would say industrial grout with sand and latex additive.
The project budget, scale and environment will dictate the material formulas and extruder specifications, which are probably kept secret by those that are already in the business.
Probably a good business to get into if you know the required science and engineerin
See less