Module III Concrete Hollow Blocks PDF

MISCELLANEOUS CONSTRUCTION MATERIALS PREPARED BY: ANGELA KHRYSS T. ABUEL ENGINEER II DPWH-BATANGAS III DISTRICT ENGINEERING OFFICE CONCRETE HOLLOW BLOCKS (CHB) CONCRETE HOLLOW BLOCKS (CHB) A pre-cast hollow building unit with cells composed of Portland Cement, suitable aggregates, with or wi...

MISCELLANEOUS CONSTRUCTION MATERIALS PREPARED BY: ANGELA KHRYSS T. ABUEL ENGINEER II DPWH-BATANGAS III DISTRICT ENGINEERING OFFICE CONCRETE HOLLOW BLOCKS (CHB) CONCRETE HOLLOW BLOCKS (CHB) A pre-cast hollow building unit with cells composed of Portland Cement, suitable aggregates, with or without inclusions of other materials Face shell- the surface of a concrete hollow block exposed on either side of the wall shall be flat and rectangular opposite faces shall be parallel and all adjacent sides shall be perpendicular Web- a part of concrete hollow blocks which connects the two faces Core- holes between the webs Ears/Edge- vertical ends of the face shells, on either side of the end shells COMPOSITION OF CONCRETE HOLLOW BLOCKS 1. Cementitious Materials 1.1 Portland Cements - ASTM C 150 1.2 Blended Cements - ASTM C 595 1.3 Hydrated Lime, Type S - ASTM C 207 1.4 Pozzolans - ASTM C 618 COMPOSITION OF CONCRETE HOLLOW BLOCKS 2. Mineral Aggregates- consists of natural sand or manufactured sand 2.1 Normal Weight- ASTM C33 (Specification for Concrete Aggregates) 2.2 Light Weight- ASTM C331 (Specification for Lightweight Aggregates Concrete Masonry Units) 3. Water- should be free from significant amount of deleterious impurities SIZE AND SHAPE Hollow blocks may be rectangular or segmented and when specified shall have an end shape to provide interlock at vertical joints. Units of unusual size, shape and strength maybe sawed into segments, some or all of which shall be tested individually in the same manner as prescribed for full-size units. The strength of the full size-units shall be considered as that which is calculated from the average measured strength of the specimens. CLASSIFICATIONS OF CONCRETE HOLLOW BLOCKS Load Bearing Hollow blocks – these are blocks whose thickness ranges from 6 to 8 inches or more, a hollow blocks capable of carrying super imposed load aside from its own weights. Uses: Use in exterior wall below grade and for unplastered exterior wall above grade that may or may not be exposed to weather Non-load Bearing Hollow blocks – these are blocks whose thickness ranges from 3 to 4 inches, a hollow blocks not capable of carrying super imposed load carrying their own weights only. Uses: Intended for walls, partitions, fences or dividers SPECIFICATIONS FOR CONCRETE HOLLOW BLOCKS ASTM C-90: LOAD BEARING CONCRETE MASONRY UNITS Strength Requirements: Individual -5.5 Mpa (800 psi) Minimum Average -6.9 Mpa (1000 psi) Minimum Absorption - 240 kg/cu.m. Maximum (Average of 3 units) Moisture Content - 45% Maximum (Average of 3 units) SPECIFICATIONS FOR CONCRETE HOLLOW BLOCKS ASTM C-129: NON-LOAD BEARING CONCRETE MASONRY UNITS Strength Requirements: Individual -3.45 Mpa (500 psi) Minimum Average -4.14 Mpa (600 psi) Minimum Absorption - - Moisture Content - - SAMPLING AND TESTING REQUIREMENTS Delivered units shall be inspected of the following:  It should be sound (in good condition and solid)  Free from cracks  Free from other defects One (1) Quality Test – every 10,000 units or fraction thereof Specimens- 6 pieces for one (1) Quality Test 3 specimens for Compression Test 3 specimens for Moisture Content and Water Absorption DETERMINATION OF COMPRESSIVE STRENGTH TEST OF CONCRETE MASONRY UNITS Significance: Compression Test is performed on concrete masonry units such as solid load, hollow load, and non- load bearing blocks in order to determine its strength properties. The test is important for the evaluation of compressive strength as a basis of acceptance. Test Sample: Three (3) full-size units taken from each lot of 10,000 units or fraction thereof Apparatus : Steel scale having divisions not greater than 2.5mm. Compression machine with an accuracy of +/- 1% over the anticipated load range. Thickness of Steel Plates as Bearing Block: 12.7mm; min. DETERMINATION OF COMPRESSIVE STRENGTH TEST OF CONCRETE MASONRY UNITS PROCEDURE:  MEASUREMENTS OF DIMENSIONS For each unit, measure and record the width (W) across the top and bottom bearing surfaces at midlength, height (H) at mid-length of each face, and length (L) at mid-height of each face.  COMPRESSIVE STRENGTH TEST Position the specimens on compression machine with the upper bearing block. Apply the load up to one half of the expected maximum load at any convenient rate, after which adjust the controls of the machine as required to give a uniform rate of travel of the moving head such that the remaining load is applied in not less than 1 nor more than 2 min. Record the maximum compressive load in pounds (newtons) as Pmax. MEASUREMENT OF DIMENSIONS Length : Measure length (L) on the longitudinal center line of each face actual length=16”(390mm) Width : Measure width (W) across the top and bottom bearing surfaces at mid-length actual width=4”(90mm),6”(140mm),8”(190mm),10”(250mm),12”(300mm) Height : Measure height (H) on both faces at mid-length actual height=8”(190mm) DIMENSION MEASUREMENT OF CONCRETE HOLLOW BLOCKS DETERMINATION OF COMPRESSIVE STRENGTH TEST OF CONCRETE MASONRY UNITS Calculation: Maximum Load, newtons (or pound-force) Compressive Strength = ------------------------------------------ Gross Cross-Sectional Area of the Unit,mm2 Gross Cross Sectional Area of the Unit (mm2) is the total area of a section perpendicular to the direction of the load, including areas within cells. Gross Cross-Sectional Area = Length x Width COMPRESSION TEST OF CONCRETE HOLLOW BLOCKS DETERMINATION OF ABSORPTION AND MOISTURE CONTENT OF CONCRETE MASONRY UNITS Significance: Absorption and moisture content tests of concrete masonry units are performed so as to determine the actual percentage of water and the absorption characteristic of the concrete when subjected in a saturated condition. The values of this are necessary in the evaluation relative to its permissible value of acceptance. Test Sample: Three (3) full-size units taken from each lot of 10,000 units or fraction thereof Apparatus 1. Oven with temperature control up to 115 ºC 2. Balance sensitive within 0.5% of the weight 3. Container for saturating samples DETERMINATION OF ABSORPTION AND MOISTURE CONTENT OF CONCRETE MASONRY UNITS Procedure 1. Dry the specimen in a ventilated oven to a temperature of 100 to 115 Degree Celsius for not less than 24 hours to a constant weight and obtain the dry weight. 2. Immerse completely the test specimen in a container with water at room temperature of 15.6 ⁰C to 26.7 ⁰C for 24 hours. 3. Weigh the specimens while suspended by a metal wire and completely submerged in water. 4. Remove from the water and allow to drain for one (1) minute by placing them on a 9.5mm or coarser wire mesh. Wipe visible surface water with damp cloth and immediately weigh. Calculations: Wet mass of the Dry mass of the sample, g - sample, g Absorption, kg/m3 = ---------------------------------------------------------- x 1000 Wet mass of the Immersed mass sample, g - of the sample, g Wet mass of the Dry mass of the sample, g - sample, g Absorption, % = ------------------------------------------------------- x 100 Dry mass of the sample, g Mass of the Dry mass of the sample, g - sample, g Moisture Content, % = -------------------------------------------------------- x 100 Wet mass of the Dry mass of the sample, g - sample, g ABSORPTION TEST: WEIGHING AND SOAKING OF CONCRETE HOLLOW BLOCKS ABSORPTION TEST FOR CONCRETE HOLLOW BLOCK  WORK SHEET FOR TESTS ON CONCRETE HOLLOW BLOCKS Project __________________________________________________________________________________________ Proposed use ______________________________________ Spec’s Item No. _________________________________ Tested by__________________________________________ Computed by __________________________________ (Name and designation) (Date) (Name and designation) (Date) Sample Identification 1 2 3 1. Width, mm - - - - - - - - - - - - 150 150 150 2. Length, mm - - - - - - - - - - - 400 400 400 3. Height, mm - - - - - - - - - - - 200 200 200 60,000 60,000 60,000 4. Gross-cross sectional area, mm - - 5. Compressive Strength: 66,000# 76,000# 67,000# Ultimate Load, kg 4.9 5.6 5.0 Compressive Strength, MN/m2 5.2 Compressive Strength, MN/2 (Avg. of 3 units) 6. Moisture Content and water absorption: Mass as Dry Wet Immersed Sample ID Sampled (1) g Mass (2) g Mass (3) g Mass (4) g 1 1570 1524 1678 903 2 1506 1466 1580 886 3 1923 1882 2070 1116 Average 1666 1624 1776 968 COMPUTATION: Moisture Content, % (1) - (2) 1666 - 1624 --------------- x 100 = -------------------- x 100 = 28 (3) - (2) 1776 - 1624 Water absorption, kg/m3 (3) - (2) 1776 - 1624 ------------------ x 1000 -------------------- x 1000 = 188 (3) - (4) 1776 - 968 66000 # x 4.448222 N/1# 1. CS, N/mm2 = --------------------------------- = 4.9 60,000 mm2 76,000 # x 4.448222 N/1# 2. CS, N/mm2 = ----------------------------------- = 5.6 60,000 mm2 67,000 # x 4.448222 N/1# 3. CS, N/mm2 = ------------------------------------- = 5.0 60,000 mm2  Republic of the Philippines Department of Public Work s And Highways BUREAU OF RESEARCH AND STANDARDS EDS A, Diliman, Quezon City Lab. Report No.: 8-300-05 23 August 2005 (Date) TEST REPORT ON CONCRETE MASONRY UNITS Project : Imprv't. of MPB, Poblacion Alitagtag, Batangas/Const. of School Bldg. at Cuenca NHS, Cuenca, Batangas & Const. of MPB Poblacion 3 Sto. Tomas, Batangas Type of Unit : Concrete Hollow Blocks, Non-Load Bearing Quantity represented : 10,000 pcs. Sampled at : Stockpile at Jobsite Original source : Lito's Builders Supplied by : MGDJ Const./Juber Const./Bedun Const. Proposed use : Walling Spec's Item No. : ASTM C-129 Sampled by : J. Sanciangco/F. Opena, Lab. Tech. II MGDJ Const./DPWH-Bats. 3rd DEO 7-26-05 (Name & designation) (Office) (Date) Submitted by : Ma. Belen M. Marquez DPWH-Bats. 3rd DEO 8-05-05 (Name & designation) (Office) (Date received) Lab. No. : 3372-05 (Paid under OR # 3709747) SAM PLE I.D. TESTS REQUIREM ENTS RESULTS CICC-2 Dimension Measurement, mm Width 1 - 120 2 - 118 3 - 121 Length 1 - 400 2 - 402 3 - 401 Height 1 - 200 2 - 200 3 - 201 Compressive Strength, MN 2 Individual Unit 1 3.45 Min. 1.06* 2 3.45 Min. 1.43* 3 3.45 Min. 1.43* Average of three(3) units 4.14 Min. 1.31* Water Absorption,kg 3 (Avg. of 3 units) - 250 Moisture Content, %(Avg.of 3 units) - 50 REM ARKS : *Sample fails to meet Specification. Che cke d by: Te s te d by : L. Casanova T. Urmaza CLARITA C. FLORES S. Orate Engine e r V J. Bergonio ATTESTED: J. Tagalo Witne s s e d by : B ASILIA S. VILLANUEVA JUDY F. SESE Engineer IV OIC, B ure au Dire ctor  Republic of the Philippines Department of Public Work s And Highways BUREAU OF RESEARCH AND STANDARDS EDS A, Diliman, Quezon City Lab. Report No. : 3-191-05 M arch 31, 2005 (Date) TEST REPORT ON CONCRETE MASONRY UNITS Project Cons t. Including RROW of Molino Blvd. Aguinaldo Highway (Niog Road Section) Bacoor, Cavite Type of Unit Concrete Hollow Blocks(Non-Load Bearing ) 6" thick Quantity represented : 10,000 Pcs. Sampled at Jobsite Original source - Supplied by E.M. Aragon Enterprises Proposed use Manhole Spec's Item No. : ASTM C-129 ( Non Load Bearing ) Sampled by M. Cac- Engr. II DPWH-Region IV-A, EDSA, Q.C. 3-11-05 : (Name & designation) (Office) (Date) Submitted by -do- -do- 3-15-05 : (Name & designation) (Office) (Date received) Lab. No. : 1108-05 (Paid under OR 3709256) SAM PLE I.D. TESTS REQUIREM ENTS RESULTS Dimension Measurement, mm CMB Width 1 - 150 2 - 150 3 - 150 Length 1 - 390 2 - 390 3 - 390 Height 1 - 195 2 - 195 3 - 195 2 Compressive Strength, MN/m Individual Unit 1 3.45 Min. 4.49 2 3.45 Min. 4.63 3 3.45 Min. 4.56 Average of three (3) units 4.14 Min. 4.56 Water absorption, kg/m 3 (Average of 3 units) - 119 Moisture Content, % (Avg. of 3 units) - 35 REM ARKS : Sample meets Specification. Te s te d by : Che cke d by: L. Cas anova J. Tagalo T. Urmaza J. B e rgonio CLARITA C. FLORES Engine e r V ATTESTED : Witne s s e d by : B ASILIA S. VILLANUEVA Engine e r IV JUDY F. SESE OIC, B ure au Dire ctor THANK YOU AND HAVE A GREAT DAY!