Prelims - Modules 1, 2, 3, 4, 5

Question 1

________is a general term meaning the art and science to form objects, systems, or organizations

Answer 1

Construction

Question 2

________means an article, material, or supply brought to the construction
site by the Contractor or a subcontractor for incorporation into the building or work. The term also includes an item brought to the site preassembled from articles, materials, or supplies.

Answer 2

Construction Materials

Question 3

_________ testing involves the essential examination of all materials used in the construction of a project. Industry players need to ensure that their products can withstand certain conditions and comply with increasingly complex national and international building standards and regulations. If they are unable to do so, building projects may be delayed, and quality may be compromised, resulting in increased liability risks and a shortened lifespan of their assets

Answer 3

Construction materials testing

Question 4

________ ________are responsible for the selection, specification, and quality control of materials to be used in a job. When engineers select the material for a specific application, they must consider various criteria and make compromises. Both the client and the purpose of the facility or structure dictate, to a certain extent, the emphasis that will be placed on the different criteria.

Answer 4

Materials Engineers

Question 5

________ and ________ must be familiar with materials used in the construction of a wide range of structures. Materials most frequently used include steel, aggregate, concrete, masonry, asphalt, and wood. Materials used to a lesser extent include aluminum, glass, plastics, and fiber-reinforced composites. Geotechnical engineers make a reasonable case for including soil as the most widely used engineering material since it provides the basic support for all civil engineering structures.

Answer 5

Civil and Construction Engineers

Question 6

A ________, is a device for separating wanted elements from unwanted material or for characterizing the particle size distribution of a sample of aggregates, sand, and other soil particles.

A set of ________ of sizes: 80mm, 63mm, 50mm, 40mm, 31.5mm, 25mm, 20mm, 16mm, 12.5mm, 10mm, 6.3mm, 4.75mm, 3.35mm, 2.36mm, 1.18mm, 600μm, 300μm, 150μm, and 75μm.

A balance or scale with an accuracy to measure 0.1 percent of the weight of the test sample. The weight of the sample available should not be less than the weight given on the next page.

https://m.media-amazon.com/images/I/81M3gnJQB7L.SL1500.jpg

Answer 6

Sieve Set

https://m.media-amazon.com/images/I/81M3gnJQB7L.SL1500.jpg

Question 7

________ helps to determine the particle size distribution of the coarse and fine aggregates. This is done by sieving the aggregates as per IS: 2386 (Part I) – 1963. In this process, different sieves, as standardized by the IS code, are used to pass the aggregates through them, collecting the different-sized particles left on each sieve.

Answer 7

Sieve Analysis

Question 8

used to accurately determine the mass or weight of an item or substance within a specific weight range and to a particular readability

https://5.imimg.com/data5/ZZ/ZI/AW/SELLER-411288/laboratory-balance-500x500.jpg

Answer 8

Balance

https://5.imimg.com/data5/ZZ/ZI/AW/SELLER-411288/laboratory-balance-500x500.jpg

Question 9

typically graduated or marked on the side with lines that indicate the contained volume

https://www.labkafe.com/storage/school-catalogue-images/lkch-112-5.jpg

Answer 9

Graduated Beaker

https://www.labkafe.com/storage/school-catalogue-images/lkch-112-5.jpg

Question 10

A metal mold in the form of a truncated cone with a top diameter of 4” (102 mm), a bottom diameter of 8” (203 mm), and a height of 12” (305 mm) is used to fabricate the specimen for a slump test. Additionally, a 2 ft (610 mm) long bullet-nosed metal rod, 5” (16 mm) in diameter, is used in the test.

https://www.matest.com/contents/products/c182p-kit.jpg

Answer 10

Slump Cone

https://www.matest.com/contents/products/c182p-kit.jpg

Question 11

The ________is an empirical test that measures the workability of fresh concrete.

More specifically, it measures the consistency of the concrete in that specific batch. This test is performed to check the consistency of freshly made concrete.

Consistency is a term very closely related to workability. It describes the state of fresh concrete and refers to the ease with which the concrete flows, indicating the degree of wetness. The workability of concrete is mainly affected by its consistency.

For example, wetter mixes will be more workable than drier mixes, but concrete of the same consistency may still vary in workability.

Answer 11

Concrete Slump Test

Question 12

device that performs arithmetic operations on numbers

https://upload.wikimedia.org/wikipedia/commons/thumb/c/cf/Casio_calculator_JS-20WK_in_201901_002.jpg/1200px-Casio_calculator_JS-20WK_in_201901_002.jpg

Answer 12

Calculator

https://upload.wikimedia.org/wikipedia/commons/thumb/c/cf/Casio_calculator_JS-20WK_in_201901_002.jpg/1200px-Casio_calculator_JS-20WK_in_201901_002.jpg

Question 13

________sturdy, durable containers used to shape and hold cement until it hardens. These ________ are often made of robust materials such as silicone rubber, urethane rubber, and even plastic. They come in different shapes and sizes to offer you variety to suit your project.

https://sunlabtech.com/wp-content/uploads/2018/08/Concrete-mould.jpg

Answer 13

Various Moulds

https://sunlabtech.com/wp-content/uploads/2018/08/Concrete-mould.jpg

Question 14

150mm x150mm x 150mm

100mm x100mm x 100 mm

70.6mm x 70.6mm x 70.6mm

https://www.ele.com/cms-files/53c3/53c3eb9b1eda0_large.jpg

Answer 14

Cube Moulds

https://www.ele.com/cms-files/53c3/53c3eb9b1eda0_large.jpg

Question 15

6 x 12 in. (15.2 x 30.5 cm)

4 x 8 in (10 x 20 cm

https://www.globalgilson.com/content/images/thumbs/0026107_cast-iron-concrete-cylinder-molds.jpeg

Answer 15

Cylinder Moulds

https://www.globalgilson.com/content/images/thumbs/0026107_cast-iron-concrete-cylinder-molds.jpeg

Question 16

100mm x 100mm x 400mm

100mm x 100mm x 500mm

150mm x 150mm x 600mm

https://www.smi-group.com.ph/wp-content/uploads/2020/08/Beam-Mold.jpg

Answer 16

Beam Moulds

https://www.smi-group.com.ph/wp-content/uploads/2020/08/Beam-Mold.jpg

Question 17

A ________is an instrument used to measure the specific gravity (or relative density) of liquids, which is the ratio of the density of the liquid to the density of water.

A ________is usually made of glass and consists of a cylindrical stem and a bulb weighted with mercury or lead shot to make it float upright. The liquid to be tested is poured into a tall container, often a graduated cylinder, and the hydrometer is gently lowered into the liquid until it floats freely. The point at which the surface of the liquid touches the stem of the hydrometer is noted. Hydrometers usually contain a scale inside the stem, allowing the specific gravity to be read directly. A variety of scales exist and are used depending on the context.

https://upload.wikimedia.org/wikipedia/commons/e/e8/Hydrometer6455.png

Answer 17

Hydrometer

https://upload.wikimedia.org/wikipedia/commons/e/e8/Hydrometer6455.png

Question 18

________An instrument is designed to exert tensile, compressive, or transverse stress on a specimen under test. It can also be adapted for determining Brinell hardness, ductility, cold bend, and other properties. The machine essentially consists of three systems: loading, weighing, and indicating, with the loading being applied either mechanically or hydraulically.

https://bluestar-ee.com/wp-content/uploads/2021/12/hydraulic-universal-testing-machines-analog-480x320.jpg

Answer 18

Universal Testing Machine

https://bluestar-ee.com/wp-content/uploads/2021/12/hydraulic-universal-testing-machines-analog-480x320.jpg

Question 19

________(also commonly called a cement mixer) is a device that homogeneously combines cement, aggregate such as sand or gravel, and water to form concrete. A typical concrete mixer uses a revolving drum to mix the components. For smaller volume works, portable concrete mixers are often used so that the concrete can be made at the construction site.

https://m.media-amazon.com/images/I/61Vg4S-gDtL.AC_SL1500.jpg

Answer 19

Concrete Mixer

https://m.media-amazon.com/images/I/61Vg4S-gDtL.AC_SL1500.jpg

Question 20

________instrument for measuring the condition of a fluid (liquid or gas) that is specified by the force that the fluid would exert, when at rest, on a unit area, such as pounds per square inch or newtons per square centimetre.

https://res.cloudinary.com/rsc/image/upload/b_rgb:FFFFFF,c_pad,dpr_2.625,f_auto,h_214,q_auto,w_380/c_pad,h_214,w_380/Y2190823-01?pgw=1

Answer 20

Pressure Gauge

https://res.cloudinary.com/rsc/image/upload/b_rgb:FFFFFF,c_pad,dpr_2.625,f_auto,h_214,q_auto,w_380/c_pad,h_214,w_380/Y2190823-01?pgw=1

Question 21

________is a round, straight steel rod used with concrete cylinder molds, slump cones and unit weight tests. It measures 5/8″ diameter by 24″ length. Both ends are rounded to a hemispherical tip.

https://lh5.googleusercontent.com/proxy/iMZG7Vc8od8L9k0kzSZxHL5yPqpmmTE-_TYq3ckurMqM9h8GwY11GTScPu98tkW_zZya2GJ3S7U06G_nx1tWDS5GnUEu5RuzICTyDq7xxL_LRyJlWfNEBOJVhmPoFRQIxEX0zNFsSOpM4zSeeBg1q8Y

Answer 21

Tamping Rod

https://lh5.googleusercontent.com/proxy/iMZG7Vc8od8L9k0kzSZxHL5yPqpmmTE-_TYq3ckurMqM9h8GwY11GTScPu98tkW_zZya2GJ3S7U06G_nx1tWDS5GnUEu5RuzICTyDq7xxL_LRyJlWfNEBOJVhmPoFRQIxEX0zNFsSOpM4zSeeBg1q8Y

Question 21

________is an instrument that measures temperature. It can measure the temperature of a solid such as food, a liquid such as water, or a gas such as air. The three most common units of measurement for temperature are Celsius, Fahrenheit, and kelvin. The Celsius scale is part of the metric system.

https://www.collinsdictionary.com/images/full/thermometer_554712607_1000.jpg

Answer 21

Thermometer

https://www.collinsdictionary.com/images/full/thermometer_554712607_1000.jpg

Question 22

________is a concrete tool that produces stronger concrete by vigorously shaking the concrete right after you pour it to eliminate the air bubbles or air pockets.

https://obigodtools.com.ng/wp-content/uploads/2021/08/poker-vibrator.jpg

Answer 22

Concrete Vibrator

https://obigodtools.com.ng/wp-content/uploads/2021/08/poker-vibrator.jpg

Question 23

________is used to determine the consistency, initial setting time, and final setting time of cement. In the normal consistency test, it is used to find out the amount of water needed to be added to the cement to form a cement paste of normal consistency.

________consists of an arrangement to hold a 10 mm diameter plunger and two other needles. These needles are made to freely fall into a mold filled with the cement paste, and the amount of penetration of the needles or plunger can be noted using the vertical graduations from 0 mm to 50 mm.

https://nl-test.com/images/com_hikashop/upload/nl3012x003-01-01.jpg

Answer 23

Vicat Apparatus

https://nl-test.com/images/com_hikashop/upload/nl3012x003-01-01.jpg

Question 24

To find out the consistency of cement, you have to take a sample of dried cement of about 400gweight which must pass through the 90 micron ISsieve. Then mix in it about 25% of water by weight to form a uniform paste within 2 minutes of time.

Answer 24

Consistency Test

Question 25

is a tool which is used to expose materials to a hot environment ## Footnote https://new-borel.com/products/laboratory-ovens/thermonatural-ovens-350-c/b373620a596114321a0.jpg

Answer 25

Oven ## Footnote https://new-borel.com/products/laboratory-ovens/thermonatural-ovens-350-c/b373620a596114321a0.jpg

Question 26

is a watch with buttons which you press at the beginning and end of an event, so that you can measure exactly how long it takes. ## Footnote https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcR1QEzS6IxR0ozonlF5kK6qI89JObu3PSE1_Q&s

Answer 26

Stop Watch ## Footnote https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcR1QEzS6IxR0ozonlF5kK6qI89JObu3PSE1_Q&s

Question 27

It is used to channel liquid or fine-grained substances into containers with a small opening. ## Footnote https://upload.wikimedia.org/wikipedia/commons/thumb/1/11/Kitchen_Funnel.jpg/1200px-Kitchen_Funnel.jpg

Answer 27

Funnel ## Footnote https://upload.wikimedia.org/wikipedia/commons/thumb/1/11/Kitchen_Funnel.jpg/1200px-Kitchen_Funnel.jpg

Question 28

are containers made from woven wires that can also be used in place of plastic baskets and are used to store or organize materials in both household and commercial lines of work. ## Footnote https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSS9VhYA5uDM-JLr_6bfzqXDRMwhNP9xoWHJA&s

Answer 28

Wire Basket ## Footnote https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSS9VhYA5uDM-JLr_6bfzqXDRMwhNP9xoWHJA&s

Question 29

used regularly for the thorough, manual cleaning of lab glassware and plasticware. They typically have a handle with terminal bristles, set centrally or laterally, and come in a range of sizes and styles for the effective cleaning of most types of vessel without leaving scratches or other damage. ## Footnote https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQ9Vwl8kiQn7KRYWivzcdVCnmA9krsSNQmlzg&s

Answer 29

Brush ## Footnote https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQ9Vwl8kiQn7KRYWivzcdVCnmA9krsSNQmlzg&s

Question 30

are used in a number of agricultural machines, such as tractors, to raise and lower tools and equipment to the proper working height. Marine. It facilitate the construction of ships and are used to load large components onto finished boats and ships. Aerospace. ## Footnote https://upload.wikimedia.org/wikipedia/commons/thumb/3/33/מגבה_של_קרוואן.jpg/1200px-מגבה_של_קרוואן.jpg

Answer 30

Hydraulic Jack ## Footnote https://upload.wikimedia.org/wikipedia/commons/thumb/3/33/מגבה_של_קרוואן.jpg/1200px-מגבה_של_קרוואן.jpg

Question 31

is a tool used to dig as well as to move loose, granular materials (like dirt, gravel, grain, or snow) from one spot to another, and. a spade is a tool used for digging straight-edged holes or trenches, slicing and lifting sod, and edging flower beds or lawns. ## Footnote https://www.trees.com/wp-content/uploads/files/inline-images/Pointed-Digger-Shovel.jpg

Answer 31

Shovel ## Footnote https://www.trees.com/wp-content/uploads/files/inline-images/Pointed-Digger-Shovel.jpg

Question 32

Is a durable, flat-bottomed container used in construction for mixing concrete and mortar. It ensures uniform blending of dry ingredients (cement and aggregates) before adding water to create a consistent mixture. The steel pan is also used for transporting mixed materials and can be easily cleaned for reuse. ## Footnote https://t3e5d2a5.rocketcdn.me/wp-content/uploads/2016/11/Stainless-Steel-Freeze-Thaw-Mold-H-3185TM_lg-266x266.jpg

Answer 32

Steel Pan ## Footnote https://t3e5d2a5.rocketcdn.me/wp-content/uploads/2016/11/Stainless-Steel-Freeze-Thaw-Mold-H-3185TM_lg-266x266.jpg

Question 33

is a handheld tool that can be used for mixing mortar, applying mortar, smoothing concrete, patching concrete, and more! This versatile tool has many uses in the construction industry and is incredibly helpful. ## Footnote https://i.ebayimg.com/images/g/6OQAAOSwAt1i~bVB/s-l400.jpg

Answer 33

Trowel ## Footnote https://i.ebayimg.com/images/g/6OQAAOSwAt1i~bVB/s-l400.jpg

Question 34

is not just limited to transporting cement; it is also a versatile tool for mixing cement on construction sites. With its deep and spacious tray, the wheelbarrow provides an ideal space for creating the perfect consistency of cement. ## Footnote https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSa0_p4Tn2PtaWT8kqyv8OUvuxgmWVoBdpj-w&s

Answer 34

Wheel Barrow ## Footnote https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcSa0_p4Tn2PtaWT8kqyv8OUvuxgmWVoBdpj-w&s

Question 35

is specially designed to address the injuries and accidents that may occur on the site. These kits typically contain a variety of medical supplies, including bandages, gauze, plasters, burn dressings, eye wash, and a First Aid For Construction Poster. ## Footnote https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQQr_6KG_hyVcHZKtNacF9YKZzTYAe-JX5NuQ&s

Answer 35

First Aid Box ## Footnote https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcQQr_6KG_hyVcHZKtNacF9YKZzTYAe-JX5NuQ&s

Question 36

A _______ is a characteristic of matter that can be observed and measured without changing the chemical identity of the sample. A _______ might involve a physical change but not a chemical change.

Answer 36

Physical property

Question 37

_______ is the ratio of mass to the volume of the material in its natural state, including voids and pores. It is expressed in kg/m³. _______ influences the mechanical properties of materials like strength, heat, and conductivity, etc.

Answer 37

Bulk Density

Question 38

_______ gives the volume of the material occupied by pores. It is the ratio of the volume of pores to the volume of material. _______ influences many properties like thermal conductivity, strength, bulk density, durability, etc.

Answer 38

Porosity

Question 39

_______ is the ratio of mass of the material to its volume in a homogeneous state. Almost all the physical properties of materials are influenced by its _______ values.

Answer 39

Density

Question 40

_______ is the ratio of the mass of a given substance to the mass of a reference substance (e.g., water) for equal volumes.

Answer 40

Specific Gravity

Question 41

The ability to withstand fire without changing its shape and other properties is called _______. _______ of a material is tested by the combined actions of water and fire. Fireproof materials should provide more safety in case of fire.

Answer 41

Fire Resistance

Question 42

_______ is the ability of a material to resist freezing or thawing. It depends upon the density and bulk density of the material. Denser materials will have more _______. Moist materials have low _______ and they lose their strength in freezing and become brittle.

Answer 42

Frost Resistance

Question 43

_______ is the property of a material to withstand all atmospheric actions without losing its strength and shape. _______ affects the durability of the material. For example, corrosion occurs in iron due to _______. To resist this, a paint layer is provided.

Answer 43

Weathering Resistance

Question 44

The ability of a material to permit water through it is called _______. Dense materials like glass and metals are called impervious materials, which cannot allow water through them.

Answer 44

Water Permeability

Question 45

The capacity of a material to absorb and retain water is known as _______. It is expressed as a percentage of the weight of the dry material. It depends upon the size, shape, and number of pores in the material.

Answer 45

Water Absorption

Question 46

_______ is the property of a material to absorb water vapor from the air. It depends on relative humidity, porosity, air temperature, etc.

Answer 46

Hygroscopicity

Question 47

_______ of a material is the ratio of the compressive strength of a saturated material to its compressive strength in the dry state. It affects the strength of water-absorbent materials like soil.

Answer 47

Coefficient of Softening

Question 48

_______ is the property of a material that prevents it from melting or losing its shape at prolonged high temperatures.

Answer 48

Refractoriness

Question 49

_______ describe how a material reacts to external forces like pushing, pulling, or twisting. Strength, hardness, and elasticity are examples of _______.

Answer 49

Mechanical Properties

Question 50

The capacity of a material to resist failure caused by loads acting on it is called _______. The load may be compressive, tensile, or bending. It is determined by dividing the ultimate load taken by the material by its cross-sectional area.

Answer 50

Strength

Question 51

_______ is the property of a material to resist scratching by a harder body. The Mohs scale is used to determine the _______ of a material.

Answer 51

Hardness

Question 52

The capacity of a material to regain its initial shape and size after the removal of load is known as _______ and the material is called an elastic material. Ideally, elastic materials obey Hooke’s law, in which stress is directly proportional to strain.

Answer 52

Elasticity

Question 53

When a load is applied to a material, if it undergoes permanent deformation without cracking and retains this shape after the removal of the load, then it is said to be a plastic material and this property is called _______. For example, steel exhibits _______.

Answer 53

Plasticity

Question 54

When a material is subjected to a load and fails suddenly without causing any deformation, it is called a brittle material and this property is called _______. For example, concrete exhibits _______.

Answer 54

Brittleness

Question 55

If a material is subjected to repeated loads, failure occurs at some point which is lower than the failure point caused by a single, static load. This property is called _______. For example, metals can experience _______ after repeated stress cycles.

Answer 55

Fatigue

Question 56

_______ is the ability of construction materials to resist the effects of chemicals like acids, salts, and alkalis. Underground installations and constructions near the sea should be built with great _______.

Answer 56

Chemical Resistance

Question 56

_______ are any of the properties of matter that can be observed and measured only by performing a chemical change or chemical reaction. _______ cannot be determined by touching or viewing a sample; the structure of the sample must be altered for the _______ to become apparent.

Answer 56

Chemical Properties

Question 57

Formation of rust (iron oxide) in metals when they are subjected to the atmosphere is called _______. Therefore, metals should be _______ resistant.

Answer 57

Corrosion Resistance

Question 58

The properties of a material to conduct or resist electricity are called electrical properties. For example, wood has great electrical resistance, while stainless steel is a good conductor of electricity.

Answer 58

Electrical Properties of Building Materials

Question 59

The magnetic properties of materials, such as permeability, hysteresis, and magnetization, are important for understanding how materials respond to magnetic fields. These properties determine how materials interact with and are influenced by magnetic forces.

Answer 59

Magnetic Properties of Building Materials

Question 60

_______ is the property of a material to absorb heat, and it is required to design proper ventilation. It influences the thermal stability of walls. It is expressed in J/K.

Answer 60

Thermal Capacity

Question 61

_______ is the amount of heat transferred through a unit area of a specimen with unit thickness in unit time. It is measured in watts per meter per kelvin (W/m·K). It depends on material structure, porosity, density, and moisture content. Highly porous materials typically have lower _______ values.

Answer 61

Thermal Conductivity

Question 62

_______ is the ability to resist heat conduction and is the reciprocal of thermal conductivity. When it is multiplied by the thickness of the material, it gives thermal resistance. The _______ of soil varies from 30 to 500 °C-cm/W.

Answer 62

Thermal Resistivity

Question 63

_______ is the quantity of heat required to heat 1 kilogram of material by 1°C. _______ is important for understanding how materials respond to temperature changes. It is measured in J/(kg·°C).

Answer 63

Specific Heat

Question 64

Reacts with water and hardens even underwater. It is commonly used in repairs and structures exposed to water.

Answer 64

Hydraulic Cement

Question 65

The most common type of hydraulic cement used for general construction like buildings and pavements .

Answer 65

Portland Cement

Question 66

The time it takes for cement to begin losing its plasticity after mixing with water. This is crucial for tasks like shaping and applying concrete.

Answer 66

Initial Setting Time

Question 67

The period when the cement has fully hardened and can bear loads

Answer 67

Final Setting Time

Question 68

Involves allowing a needle to penetrate the cement paste until it reaches a specified depth to determine initial and final setting times.

Answer 68

Vicat Needle Method

Question 69

Uses two needles with different weights to assess the surface hardness for setting times

Answer 69

Gillmore Needle Method

Question 70

Higher water content slows the setting process.

Answer 70

Water-Cement Ratio

Question 71

Hot temperatures speed up setting, while high humidity can delay it.

Answer 71

Temperature & Humidity

Question 72

Gypsum content in cement affects how fast it sets​

Answer 72

Cement Composition

Question 73

Initial setting time defines the window for manipulating the cement paste.

Answer 73

Workability

Question 74

Final setting time determines when the material can start supporting loads

Answer 74

Structural Integrity

Question 75

Gravel, crushed stone, and blast furnace slag, typically larger than 4.75 mm​

Answer 75

Coarse Aggregates

Question 76

Sand or manufactured sand, generally smaller than 4.75 mm

Answer 76

Fine Aggregates

Question 77

This type of aggregate is sourced from natural deposits without altering its inherent properties during production processes like crushing and grinding.

Answer 77

Natural Aggregates

Question 78

This refers to artificial materials created either as a primary product or as industrial by-products. Examples include blast furnace slag, air-cooled slag, and broken bricks. Synthetic aggregates are made by thermally processing materials like expanded clay and shale, often used in the production of lightweight concrete.

Answer 78

Manufactured Aggregates

Question 79

Rounded aggregates improve workability, angular ones improve strength.

Answer 79

Shape

Question 80

Rough textures bond better with cement

Answer 80

Surface Texture

Question 81

Affects strength and stability. Heavier aggregates lead to stronger concrete.

Answer 81

Specific Weight

Question 82

Highly absorbent aggregates can lead to a weaker concrete mix​

Answer 82

Water Absorption

Question 83

Necessary for aggregates used in surfaces that face wear, such as roads

Answer 83

Abrasion Resistance

Question 84

Affects mix proportions, workability, and load-bearing capacity.

Answer 84

Bulk Density

Question 85

Important for aggregates exposed to mechanical wear (roads, pavements)​

Answer 85

Abrasion Resistance

Question 86

occurs when the cement appears to harden prematurely within minutes after mixing but can be remixed to regain its workability. The most common cause is the presence of gypsum that has partially dehydrated to form plaster of paris (CaSO4 ⋅ 1/2 H2O), which results if the temperature in the grinding mill is too high. Later, when water is added to the cement, the plaster of paris immediately starts to hydrate to gypsum and stiffen.

Answer 86

False set

Question 87

happens when the cement sets too quickly, within minutes after mixing, and cannot be reworked without adding more water. It is caused by a lack of gypsum or an incorrect sulfate-to-aluminate ratio, leading to rapid hydration of aluminates.

Answer 87

Flash set

Question 88

This issue arises when the cement takes longer than expected to set, potentially delaying the construction process. It can be caused by cold weather, excess water in the mix, or improper use of retarders.

Answer 88

Delayed Setting

Question 89

Variability in setting times can occur due to fluctuations in environmental conditions, inconsistent mixing practices, or variations in raw material quality.

Answer 89

Inconsistent setting times