Raw Material used for Concrete |
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Cement |
| Fresh cement must be used. The quality of cement is affected by moisture, air, other weathering conditions and long storage periods. UltraTech Concrete plant uses fresh cement directly procured from the cement plants through cement bulkers which in turn pump it directly into UltraTech Concrete silos thus protecting it from the external environment and humidity. |
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Coarse Aggregates |
It should be free from clay, weeds and other organic materials. The shape of aggregates should be preferably, cubical with a combination of different sizes. Elongated and flaky aggregates should be avoided. UltraTech Concrete directly sources the aggregates from selected and approved suppliers.
These aggregates are tested for:
• Shape, size and gradation (elongation/flakiness test)
• Impact value and crushing value test for their strength
• The aggregates that do not pass the above test as per Bureau of Indian Standards requirements are rejected. |
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Q)What will happen if shape of aggregates used in concrete is not rounded/cubical? |
A) If the shape of aggregates used in concrete is not rounded (or) cubical the interlocking of aggregate in concrete will not be proper and strength of concrete will decrease. If the aggregates are elongated (or) flaky the strength of concrete will be seriously affected and concrete will become porous..
In UltraTech Concrete the 20 mm & 10 mm aggregates are properly checked for elongation or flakiness and their quantity is restricted within the limits of BIS standards, to get cohesive & durable concrete. |
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Fine Aggregate |
Sand should be free from silt, clay, salts and organic materials. If silt content is more than 7 % in volume, it should be washed before use.
UltraTech Concrete directly purchases sand from selected and approved suppliers.
The sand is tested for:
• Moisture content
• Sieve analysis for fineness modlous
• Silt content
• Bad quality of sand is rejected.
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Q) How will silt in sand affect the quality of concrete? |
| A) If the sand contains excessive quantity of silt, it'll induce shrinkage cracks, adversely affecting the concrete quality and durability. |
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Q) How does the moisture in sand affect the quality of concrete? |
| A) The moisture in sand will increase the gross w/c ratio, which reduces the strength of concrete. In UltraTech Concrete plants, the moisture in sand is sensed through moisture sensors and water correction is applied automatically, thus maintaining the correct water-cement ratio as per mix design. |
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Water |
| Water should be free from impurities such as oil, alkalies, acids, salts, sugar, organic material or other substances that are deleterious to concrete and steel. Potable water is generally suitable for making concrete. Water should be tested as per BIS standards before making concrete because of the presence of dissolved salts and chemicals, which affect setting time and strength of concrete. UltraTech Concrete tests the quality of potable water at frequent intervals and in case the water needs any treatment, water purifiers are used. |
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Admixture |
| In UltraTech Concrete plants, high quality admixtures are used in concrete during mixing to improve certain properties of fresh concrete such as workability and setting time. The admixture is sourced from reputed companies and is tested for compatibility with cement before use. |
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Q) What is workability of concrete? |
A) The ease of placing, compacting and finishing of concrete in desired manner is called workability. Normally the workability is measured through slump. More the slump, higher the workability. Low slump leads to difficulties in placing of concrete. Therefore it is required to decide the workability based on experience and site conditions.
In UltraTech Concrete, workability is measured for every batch through slump cone, which is properly controlled through scientific method of dosing with admixtures. |
