Concrete Properties and Admixtures Quiz

False (B)

To speed up hydration and ensure strength development in cold conditions.

<p>lower strength</p> Signup and view all the answers

<p>Lightweight Concrete = Made by using lightweight aggregates Normal Weight Concrete = Produced using standard aggregates Heavyweight Concrete = Made with heavy aggregates</p> Signup and view all the answers

<p>Increased strength (A)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Corrosion inhibitors and waterproofing admixtures</p> Signup and view all the answers

<p>Cement B (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Water-to-cement ratio</p> Signup and view all the answers

<p>C₂S</p> Signup and view all the answers

<p>Use of Recycled Aggregates = Incorporates aggregates from demolished structures Alternative Materials = Utilizes industrial by-products like slag, fly ash, or crushed glass Smaller Aggregate Size = Creates a denser mix with improved compaction and strength Water-to-cement ratio = Determines strength and durability of concrete</p> Signup and view all the answers

<p>Admixtures (A)</p> Signup and view all the answers

<p>Water-to-cement ratio (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Adding extra water for better workability (A)</p> Signup and view all the answers

<p>Higher heat of hydration</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Ultrasonic Pulse Velocity (UPV) and Rebound Hammer Test</p> Signup and view all the answers

<p>cracks</p> Signup and view all the answers

<p>To remove voids and air pockets, resulting in higher strength and density.</p> Signup and view all the answers

<p>Rebound Hammer</p> Signup and view all the answers

<p>Water-to-cement ratio = Strength and workability Type of cement = Hydration and strength development Aggregate properties = Workability and strength Admixtures = Workability, set time, and durability Climate and environment = Type of mix required for long-term performance</p> Signup and view all the answers

<p>Surface finishing (C)</p> Signup and view all the answers

<p>Overloading = Excessive stress leading to cracking Shrinkage = Rapid drying or temperature changes causing cracks Corrosion of reinforcement = Expanding rust pushing against the concrete, causing cracks</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Ground Penetrating Radar (GPR) (C)</p> Signup and view all the answers

<p>Evaluate workability, use retarders, re-mix, or discard the batch</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Cement, aggregates (sand and gravel), and water.</p> Signup and view all the answers

<p>Use of low heat of hydration cement (D)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Corrosion of steel reinforcement</p> Signup and view all the answers

<p>non-porous</p> Signup and view all the answers

<p>Ultrasonic Pulse Velocity (UPV) = Measures uniformity of concrete and detects internal cracks or voids Half-Cell Potential Test = Assesses corrosion risk in steel reinforcement Rebound Hammer Test = Measures surface hardness and provides an indication of compressive strength</p> Signup and view all the answers

<p>Use of porous aggregates (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Reduce the impact of water penetration</p> Signup and view all the answers

<p>Excessive water content and improper mixing (B)</p> Signup and view all the answers

<p>True (A)</p> Signup and view all the answers

<p>Adequate curing and control joints.</p> Signup and view all the answers

<p>design errors</p> Signup and view all the answers

<p>Segregation = Excessive water content or improper mixing Cracking = Shrinkage, thermal stress, or overloading Bleeding = Excessive water content or low fine aggregate content</p> Signup and view all the answers

<p>Higher strength-to-weight ratio and faster construction (B)</p> Signup and view all the answers

<p>False (B)</p> Signup and view all the answers

<p>Prefabrication.</p> Signup and view all the answers

Cement A has 44% C₃S; Cement B has 64%, leading to faster early strength development in B.

Cement A has 30% C₂S, leading to slower heat of hydration; Cement B, with 14%, has a faster heat rise.

Cement A is suitable for structural elements requiring moderate strength and longer setting times.

Cement B is ideal for fast-track construction, like precast concrete and paving, due to rapid strength.

Smaller aggregates, like 10mm, create a denser mix with better compaction for higher strength.

Incorporating recycled aggregates from demolished structures helps reduce the need for natural aggregates.

Key factors include water-to-cement ratio, aggregate type, cement type, admixtures, and environmental conditions.

On-site procedures ensure strong concrete, focusing on proper mix design and curing processes.

A ratio determining concrete strength and workability.

Affects hydration rates and strength development in concrete.

Properties of aggregates that influence concrete's strength and workability.

Substances added to improve workability, set time, and durability of concrete.

The process of maintaining adequate moisture for hydration in concrete.

Factors like overloading, shrinkage, thermal expansion, and corrosion leading to cracks.

A non-destructive test that detects internal cracks and voids in concrete.

Additives that enhance workability, reduce water use, and improve concrete strength.

Enhances long-term durability in marine environments but may delay strength gain.

Can weaken fresh concrete by increasing the water-cement ratio.

Dilutes the mix, causing lower strength and durability issues.

Reduces strength and durability due to segregation and porosity.

Hampers strength development, leads to cracking and reduced durability.

Leads to poor packing, which reduces strength and increases porosity.

Caused by high chloride content in seawater, reducing durability.

Use retarding admixtures to delay setting time and maintain workability.

Ensures correct mix proportions for concrete.

Ensures uniformity and consistent properties in concrete.

Removes voids in concrete, leading to higher strength.

Standardized ratios of ingredients for simple construction projects.

Customized mix based on specific strength and environmental needs.

Separation of coarse and fine particles in concrete due to improper mixing or excess water.

Fractures in concrete caused by shrinkage, thermal stress, or excessive load.

Excess water rises to the surface of concrete, leading to weak structure.

The ability of concrete to withstand loads without failure, measured by compressive strength.

Concrete's resistance to weather, chemicals, and freeze-thaw cycles for longevity.

Techniques of mixing, curing, and placing concrete to avoid defects.

Steel bridges are lighter, stronger, and faster to assemble than concrete bridges.

A measure of how strong a material is relative to its weight, indicating efficiency.

Deterioration caused by corrosion of steel reinforcements in concrete.

Rusting of steel reinforcement inside concrete due to water penetration.

Chipping or flaking off of concrete due to expanding rust.

Cement designed to reduce heat generation during curing.

Aggregates that prevent water penetration and chemical reactions.

Measures corrosion risk in steel reinforcements through electrical potential.

Measures surface hardness of concrete indicating compressive strength.