Last Updated: 25 November 2017 © LMS SEGi

Last Updated:25 November 2017 © LMS SEGi education group 1 CE1205 CONSTRUCTION MATERIALS WEEK 9 Chapter 6 PORTLAND CEMENT PowerPoint® Slides by Salmaliza Salleh

Last Updated:25 November 2017 © LMS SEGi education group 2 Chapter Overview Chapter 6 exposed you the properties of Portland Cement and its importance in concrete mixture . You also learned different types of Portland Cement and their usage.

Last Updated:25 November 2017 © LMS SEGi education group 3 In this topic, students will be highlighted with the manufacturing process of Portland Cement, its important properties and types. Learning Objectives

Last Updated:25 November 2017 © LMS SEGi education group 4 Learning Outcomes At the end of the lesson, students should be able to list the properties of Portland cement. Students must also be able to classify different types of Portland cement.

Last Updated:25 November 2017 © LMS SEGi education group 5 Introduction There is a variety of cements available. Each type is used under certain conditions due to its special properties. Cement motar- mixture of cement, sand and water to form a paste. Cement concrete - composite product obtained by mixing cement, water, sand, and gravel Commonly used cement is Portland cement. Cement can be described as a material with adhesive and cohesive properties which make it capable of bonding mineral fragments into a compact whole.

Last Updated:25 November 2017 © LMS SEGi education group 6 The functions of cement in concrete are: To bind the sand and coarse aggregate together ___________________ in between sand and coarse aggregate particles to form a compact mass.

Last Updated:25 November 2017 © LMS SEGi education group 7 Cement is obtained by intimately mixing together calcareous and argillaceous materials, burning them at a very high temperature (1450°C), and ground the clinker to the required fineness. During grinding of clinker, gypsum is added. Calcareous materials containing calcium carbonate or lime e.g. limestone, chalk, marl Argillaceous materials containing alumina e.g. clay, shale, slate, and selected blast furnace slag

Last Updated:25 November 2017 © LMS SEGi education group 8 Types of Cement Obtain several types of cements by changing the chemical composition by varying the percentage of the four basic compounds in cement: Tricalcium silicate ( C3S) Dicalcium silicate ( C2S) Tricalcium aluminate (C3A) Terracalcium aluminoferrite (C4AF) Chemical Composition: Lime, Silica, Alumina, Iron Oxide, Magnesium, Alkalis, Sulphur trioxide.

Last Updated:25 November 2017 © LMS SEGi education group 9 Hydraulic Cement Cement that would set and hardened under water by virtue of a chemical reaction between the constituent compounds of cement and water. Consists mainly of silicates and aluminates of lime. May be classified as: Natural cement Powder obtained from clayey limestone type of natural rocks. Brown colour Not used for concrete work

Last Updated:25 November 2017 © LMS SEGi education group 10 Portland cement Burning calcareous and argillaceous materials at a very high temperature (1450°C), ground to fine powder. Most commonly used Aluminous cement Chief ingredients are calcareous (clay, shale) and aluminous materials (limestone or chalk and bauxite).

Last Updated:25 November 2017 © LMS SEGi education group 11 High Alumina Cement (HAC) Slow-setting but very rapid-hardening, thus, produces very high early strength. Concrete must be kept continuously wet for at least 24 hours from the time it begins to harden. About __________ of the ultimate strength is developed at the age of 24 hours. For the same water cement ratio, alumina cement is more workable than Portland cement. HAC concrete is more resistant than ordinary Portland cement concrete, thus suitable for under ________________ applications. Raw materials: limestone or chalk and bauxite Fusion point: 1600°C Ground to fineness of 2500 – 3200 cm2/g Colour: very dark grey powder More expensive

Last Updated:25 November 2017 © LMS SEGi education group 12 Portland Cement Raw materials used: mainly lime, silica, alumina, and iron oxide Types of Portland cement: Normal or _______________ Portland Cement (BS 12 :1971) Medium rate of hardening Most commonly used for structural purposes

Last Updated:25 November 2017 © LMS SEGi education group 13 Types of Portland Cement (continue..) ______________-hardening Portland Cement (BS 12 :1971) Similar chemical composition to OPC but different proportions More finely ground, thus increase the rate of hydration at early ages. This leads to the increased rate of early hardenings. Useful when concreting in cold weather 7 days RHPC concrete same strength with 28 days OPC concrete

Last Updated:25 November 2017 © LMS SEGi education group 14 _______________and Coloured Portland Cement Generally used for decorative work, made by China clay __________ Heat Portland Cement (BS 1370: 1974) Hardens and evolves heat more slowly than OPC The initial setting time is greater than OPC Increase of C2S, reduce C3S and C3A Portland-_______________ Cement (BS 146 : 1973) Made by grinding OPC with granulated blastfurnace slag The properties similar to OPC but hydrates slower, thus evolves less heat and hardens more slowly

Last Updated:25 November 2017 © LMS SEGi education group 15 _______________-Resisting Portland Cement (BS 4027 : 1972) Specified where there is extensive exposure to sulphates e.g. structures subjected to seawater exposure. Darker than OPC High ________________ Portland Cement Higher strength achieved by increasing C3S content and finer grinding of the clinker. _________________ Cement (BS 5224 : 1976) For hand works such as rendering and bricklaying Consists of OPC with fine inert admixture and a plasticizing agent.

Last Updated:25 November 2017 © LMS SEGi education group 16 Factors Affecting the Properties of Cement: Chemical composition Fineness Hydration of cement Setting time Soundness Loss on ignition

Last Updated:25 November 2017 © LMS SEGi education group 17 1. Chemical Composition Raw materials of OPC: lime, silica, alumina, and iron oxide Interact with each other in the kiln to form a series of more complex products The change percentage of chemical will produce different types of cement such as OPC, RHPC, LHPC or Sulphate-resisting cement. MAJOR constituents/ compound of cement: C3S – quick reaction C2S – slow reaction C3A – very quick reaction C4AF – not very important

Last Updated:25 November 2017 © LMS SEGi education group 18 2. Fineness Is a measure of the sizes of particles of cement, expressed in terms of ‘specific surface of cement’. The finer the cement is ground, the greater will be its specific surface. Determination of fineness of cement: Sieve analysis through a 90 micron sieve Specific surface area: Air permeability method Wagners turbidimeter method Fineness of different Portland Cement:

Last Updated:25 November 2017 © LMS SEGi education group 19 Fineness of different Portland Cement:

Last Updated:25 November 2017 © LMS SEGi education group 20 Fineness is the most important factor which will determines the properties of cement: The rate of hydration depends on the fineness of cement particles Rapid development of strength Leads to a faster reaction but does not alter the constituents’ properties Important in relation to the workability of concrete mixes _____________ the cohesiveness of a concrete mix Exhibit a _____________ shrinkage cracking Bleeds ___________ than a coarse aggregate

Last Updated:25 November 2017 © LMS SEGi education group 21 ANY QUESTIONS? Picture retrieved from http://www.cartoonstock.com/directory/C/Cement.asp

Last Updated:25 November 2017 © LMS SEGi education group 22 References Smith W.F. (1993). Foundations of Materials Science and Engineering, 2nd edition, McGraw-Hill International Edition Neville, A.M.(1995). Properties of Concrete, 4th edition., Addison Wesley Longman Limited, England John, V.B. (1992) Introduction to Engineering Materials, 3rd edition, McMillan Press Ltd. Everett, A. (1996). Materials, 3rd edition Addison Wesley Longman Limited, England