--- title: "Mortar properties; cement and sand for 10 cum" subject: "Building Technology" chapter: 3 key: "semester_6/building_technology:mortar-quantity-10cum" source: https://www.bctengineer.com/q/semester_6/building_technology/mortar-quantity-10cum site: BCT Engineering --- # Mortar properties; cement and sand for 10 cum Building Technology · Chapter 3: Mortars & Masonry works - Asked in: 2071 Magh, 8 marks - Video: [What Is 1.54 In Concrete & 1.33 In Mortar | Dry Volume and Wet Volume of Concrete](https://www.youtube.com/watch?v=mK0P0Q31oVY) — The Institute of Construction Managment - Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14 - Page: https://www.bctengineer.com/q/semester_6/building_technology/mortar-quantity-10cum - Whole chapter: https://www.bctengineer.com/md/semester_6/building_technology/chapter-3 ## Question What are the properties of mortar? Find out the quantities of cement and sand from the mortar used in 10 cum brick work. ## Short answer For 10 m³ brickwork with standard bricks (240x115x57 mm) and 10 mm joints using 1:4 mortar: 4777 bricks, wet mortar 2.485 m³, dry volume 3.156 m³. Cement required 0.631 m³ (≈18.2 bags of 50 kg), sand 2.53 m³. ## Answer #### Properties of mortar 1. **Workability:** easy to mix, spread and lay without segregation. 2. **Water retentivity:** holds enough water, so bricks do not absorb it quickly. 3. **Adhesion and bond strength** with brick or stone. 4. **Strength:** adequate compressive strength (1:4 cement mortar $\approx$ 7.5 N/mm² at 28 days). 5. **Durability:** resists weather, frost and chemicals. 6. **Proper setting time** and low shrinkage. 7. **Impermeable** and economical. #### Cement and sand for 10 cum brickwork The question gives no data, so assume: brick 240 x 115 x 57 mm (actual size, without mortar), 10 mm joints, mortar 1:4 (cement : sand), and dry volume = 1.27 x wet volume. **Given:** brickwork volume $= 10\ \text{m}^3$. **Step 1: Size of brick with mortar** $$ (0.25 \times 0.125 \times 0.067) = 0.002094\ \text{m}^3 $$ **Step 2: Number of bricks** $$ N = \frac{10}{0.002094} = 4776.1 \approx 4777\ \text{bricks} $$ **Step 3: Volume of bricks without mortar** $$ 4777 \times 0.24 \times 0.115 \times 0.057 = 7.515\ \text{m}^3 $$ **Step 4: Wet volume of mortar** $$ 10 - 7.515 = 2.485\ \text{m}^3 $$ **Step 5: Dry volume of mortar** (add 27% for dry bulk, voids in sand, wastage and shrinkage) $$ 2.485 \times 1.27 = 3.156\ \text{m}^3 $$ **Step 6: Cement and sand** for 1:4 (sum of ratio $= 5$) $$ \text{Cement} = \frac{1}{5} \times 3.156 = 0.631\ \text{m}^3 = 909\ \text{kg} \approx 18.2\ \text{bags (50 kg, 0.0347 m}^3\text{ each)} $$ $$ \text{Sand} = \frac{4}{5} \times 3.156 = 2.525\ \text{m}^3 $$ **Answer: Cement = 0.631 m³ (about 18.2 bags); sand = 2.53 m³.** ## Check yourself The answer's key points as multiple-choice questions, with the correct option and why. 1. Which property means the mortar holds water so that bricks do not suck it out quickly? A. Workability B. Water retentivity C. Impermeability D. Setting time Answer: B. Water retentivity keeps enough water in the mortar for cement hydration despite absorbent bricks. (Key point: Mortar properties) 2. What approximate compressive strength is quoted for 1:4 cement mortar? A. 0.5 N/mm^2 B. 5 N/mm^2 C. 50 N/mm^2 D. 15 N/mm^2 Answer: B. The answer gives about 5 N/mm^2 for 1:4 cement mortar. (Key point: Mortar strength) 3. From 10 m^3 brickwork, wet mortar is 2.485 m^3. What is the dry volume? A. 2.485/1.27 = 1.957 m^3 B. 2.485 + 1.27 = 3.755 m^3 C. 2.485 x 1.5 = 3.73 m^3 D. 2.485 x 1.27 = 3.156 m^3 Answer: D. Dry volume = 1.27 x wet volume = 3.156 m^3. (Key point: Wet to dry volume) 4. With dry volume 3.156 m^3 and mix 1:4, what are cement and sand? A. 0.631 m^3 cement, 3.156 m^3 sand B. 0.631 m^3 cement, 2.525 m^3 sand C. 0.451 m^3 cement, 2.705 m^3 sand D. 0.789 m^3 cement, 2.367 m^3 sand Answer: B. Sum of ratio = 5: cement = 3.156/5 = 0.631 m^3, sand = 4/5 x 3.156 = 2.525 m^3. (Key point: Cement and sand 1:4) ## Related in Building Technology - [Masonry work, materials for 20 cum brickwork](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Abrickwork-20cum-1to6) — Building Technology, chapter 3 - [Cement and sand for 100 m² plastering numerical](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aplaster-100m2-1to6) — Building Technology, chapter 3, asked 2× - [Cement and sand for 200 m² plastering numerical](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Aplaster-200m2-1to5) — Building Technology, chapter 3, asked 2× - [Mortar for 10 m³ brickwork (1:4) numerical](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Amortar-10m3-1to4) — Building Technology, chapter 3 - [First class brickwork in 1:6 mortar numerical](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Amortar-first-class-1to6) — Building Technology, chapter 3 - [Preparing cement mortar by manual process](https://www.bctengineer.com/question.md?key=semester_6%2Fbuilding_technology%3Amortar-prep-manual) — Building Technology, chapter 3, asked 2× ## Related in other subjects - [Detailed specification of brick work in 1:4 mortar](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-brick-1-4) — Construction Management, chapter 12, asked 5× - [Detailed specification of brick work in 1:6 mortar](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-brick-1-6) — Construction Management, chapter 12, asked 5× - [Detailed specification of cement sand mortar 1:4](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-cs-mortar-1-4) — Construction Management, chapter 12, asked 2× - [Detailed specification of cement sand mortar 1:6](https://www.bctengineer.com/question.md?key=semester_8%2Fconstruction_management%3Adetailed-spec-cs-mortar-1-6) — Construction Management, chapter 12, asked 2×