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Correct option is (b) C3S

To explain: HIGHER C3S→higher early strength-higher HEAT GENERATION (roads, cold ENVIRONMENTS). Higher CS→lower early strength-lower heat generation (dams).

Correct answer is (c) GRANULATOR

For explanation: The blended meal is sieved and fed into a rotating dish CALLED a granulator, WATER weighing about 12% of the meal being added at the same TIME.

The correct OPTION is (a) 1300-1600 °C

For explanation: 1300-1600 °C is the best range to melt the RAW materials for a healty PC. Below 1300 °C the materials whcih we ADDED to MAKE PC won’t melt perfectly and the result will be unhealty PC.

The correct answer is (d) 1400° and 1500°C

The EXPLANATION is: In this process calcareous material such as LIME stone (CALCIUM carbonate) and argillaceous material such as clay are ground separately to fine powder in the ABSENCE of WATER and then are mixed together in the desired proportions.

Correct option is (a) .15-5 CM

To ELABORATE: As the materials pass through the kiln their TEMPERATURE is rised UPTO 1300-1600 °C. The process of heating is named as “burning”. The output is known as “CLINKER” which is 0.15-5 cm in diameter.

Right option is (c) C3A

The EXPLANATION is: C3A is characteristically fast reacting with WATER & may lead to a rapid stiffening of the paste with a large amount of the heat generation (Flash-Set)-(Quick-Set).

Correct choice is (b) Chemical reaction of cement with water

Easy explanation: As water COMES into contact with cement particles, HYDRATION REACTIONS immediately STARTS at the surface of the particles.

The correct option is (b) Rotary kiln

To EXPLAIN: The slurry with the desired LIME CONTENT PASSES into the rotary kiln up to 8 m in DIAMETER and length 230m.

Correct choice is (c) 2-6%

The BEST I can EXPLAIN: PORTLAND cement is made by mixing substances CONTAINING CaCO3 with substances containing SiO2, Al2O3, Fe2O3 and heating them to a clinker which is subsequently ground to POWDER and mixed with 2-6 % gypsum.

Correct choice is (b) P.C. + WATER + Sand

The explanation is: Mortar is a mixture of 3 materials i.e. cement, water and sand (P.C. + sand + water = Mortar), used in BUILDING for holding BRICKS or stones together.

Correct choice is (C) 15mm

For explanation: Hard pellets about 15 MM in diameter are FORMED. The pellets are baked hard in a pre-heating grate by MEANS of hot gases from the kiln.

Correct choice is (a) True

The explanation is: The kiln SIZE is BIGGER for WET process than for DRY process to manufacture the CEMENT because much of the kiln’s length was used up for the drying process.

Right answer is (a) 6m and 200m

Easy explanation: They are PRODUCED in a RANGE of sizes and UNITS with diameters up to 6 m and LENGTHS up to 200 m have been made.

Right OPTION is (B) Very difficult

For EXPLANATION: It is difficult thus the RATE of hydration decreases with time & as result hydration may take several years.

The correct choice is (a) C2S

Explanation: C2S hydrates & HARDENS SLOWLY so results in less heat generation & developes most of the ultimate strength.

The CORRECT answer is (C) 75%

The best I can explain: In this process, calcareous material and argillaceous material are ground separately to fine powder in the ABSENCE of WATER and then are mixed together in the desired proportions. Dehydration zone requires a somewhat shorter distance than the WET process.

Right answer is (c) Grinding and mixing of the raw materials in their WET state

The BEST I can EXPLAIN: Grinding and mixing of the raw materials in their wet state is called wet process and grinding and mixing of the raw materials in their dry state is called dry process.

The CORRECT option is (b) C3S

To ELABORATE: C3S having a faster rate of reaction accompanied by greater heat generation developes early strength of the PASTE.

Correct ANSWER is (B) 12%

Best explanation: 12% is the MOISTURE CONTENT in slurry for dry process. The moisture content in slurry for wet process is 35-50%.

The correct OPTION is (a) True

The best I can EXPLAIN: In WET process, raw materials can be mixed easily and therefore we don’t need any extra ENERGY and due to this MACHINERY and equipments do not need much maintenance.

Correct answer is (b) CO2

To explain I WOULD say: At 900°C limestone decomposes, CaCO3.CaO + CO2 (endothermic reaction) CO2 is SWEPT AWAY by CURRENT AIR.

Right answer is (b) Gypsum

The EXPLANATION: In ORDER to prevent this rapid reaction gypsum is added to the CLINKER. Gypsum, C3A&water REACT to form RELATIVELY insoluble Calcium-Sulfo-Aluminates.

Correct answer is (b) False

To elaborate: In dry process, raw materials cannot be mixed easily and THEREFORE we need any extra energy and due to this MACHINERY and EQUIPMENTS do need much MAINTENANCE.

The correct CHOICE is (b) The amount of HEAT required is LESS, so the required FUEL amount is less

For explanation: The amount of heat required is LESSER, so the required fuel amount is less for dry process and vice-versa for wet process.

Correct option is (B) Cement rock

For EXPLANATION I would say: Cement Rock comes in Argillocalcareous Rocks. And Calcareous Rocks have Limestone, MARL, Chalk, Marine Shell DEPOSITS.

The correct OPTION is (c) do not

The best I can EXPLAIN: The raw materials is so HARD that they do not differentiate by WATER because the water might FREEZE in the mixture.

Right choice is (d) Sand

The explanation is: Sand is mixed with CEMENT to MAKE CONCRETE instead of making cement. Materials which we get from these 3 rocks are useful to make healty PC.

Right OPTION is (a) The amount of heat required is high, so the required fuel amount is high

The best I can EXPLAIN: The amount of heat required is HIGHER, so the required fuel amount is higher for wetprocess and vice-versa for dry process.

Right OPTION is (a) GRINDING and mixing of the raw materials in their dry state

Best explanation: Grinding and mixing of the raw materials in their dry state is KNOWN as dry PROCESS and grinding and mixing of the raw materials in their WET state is known as wet process.

The correct choice is (c) 1300-1450 °C

Easiest EXPLANATION: At 1300-1450 °C partial (20–30%) melting TAKES place, and BELITE reacts with calcium oxide to FORM alite.