High-Strength Concrete

To form high-strength concrete, several methods are followed and among them methods and techniques like use of admixtures, high-speed slurry mixing, prevention of cracks, Sulphur impregnation or Sulphur filling, application of cementitious aggregates, and seeding.

Given below, the details about these methods :-

1. Application of Admixture: The admixture is included to develop high-strength concrete by minimizing the water content; as a result the pores in concrete is reduced. Admixtures lessen the water content in concrete and accordingly the strength is raised with regard to plasticizer and superplasticizer.

Due to superplasticizer, the water content is decreased by up to 30%, and the necessary workability is retained. It enhances the concrete strength to a highest possible value as well as improves strength accomplishment. The plasticizer can minimize water content up to 15%.

Different types of pozzolanic materials like fly ash and silica fume belong to mineral admixtures which are normally included to the concrete mix. Due to the reaction between pozzolanic materials and Portland cement hydration product, additional C-S-H is created and extra strength is provided to concrete.

2. Impediment of Cracks: By avoiding the cracks, the high-strength of concrete can be maintained. When the crack is formed and broadcasted in concrete, it leads to concrete failure.

If 2-3% aggregate is substituted with polythene or polystyrene pieces of 0.025mm thick, it raises the compressive strength of concrete significantly.

The purpose of polythene pieces is to avoid the development of cracks devoid of additional water for the workability of fresh concrete. In the laboratory, concrete samples created with this method attain strength of 105 MPa.

Also Read: Brief explanation of 1.54 in concrete

3. High-speed Slurry Mixing: High-speed slurry mixing helps in developing the cement and water mixture earlier, and then the aggregate is included to the mix to form high-strength concrete.

The higher compressive strength of concrete can be attained with the effectiveness of cement particles, and water saved in the perfect mixing of cement paste.

4. Application of Cementitious Aggregates: The application of various cementitious aggregates like fondu, help in developing high-strength concrete. The fondu aggregate belongs to a glassy slag clinker cementitious material. It can develop strength up to 125 MPa containing a water/cement ratio of 0.32.

5. Seeding: Seeding stands for a less practical method of developing high-strength concrete. It comprises of adding a small percentage of finely ground, fully hydrated Portland cement to the fresh concrete mix.

6. Sulfur Filling or Impregnation: The impregnation of Sulphur into low-strength porous concrete is also considered as the useful method for creating the high strength concrete.

The impregnation method of concrete in the laboratory includes moist cured fresh concrete for 24hours, dry specimens at 120C for 24hours, the immersion of the specimens in molten Sulphur under vacuum for two hours, and then a release of the vacuum after two hours. The samples are then stored in molten Sulphur for half an hour. In the end, the specimens are examined.

The Sulphur impregnation method is utilized to retain the compressive strength of 58MPa in the laboratory.

7. Re-Vibration: When the water is mixed in concrete, it causes bleed that is stored at specific places and consequently continuous channels are developed, and result in shrinkage to reduce the strength of concrete.

Under this circumstance, a controlled re-vibration of concrete facilitates to reduce the detrimental influences of these factors and therefore the strength of concrete is raised.