Presentation is loading. Please wait.

Presentation is loading. Please wait.

Faculty of Applied Engineering and Urban Planning

Similar presentations


Presentation on theme: "Faculty of Applied Engineering and Urban Planning"— Presentation transcript:

1 Faculty of Applied Engineering and Urban Planning
PALESTINE UNIVERSITY Faculty of Applied Engineering and Urban Planning Dept. of Architecture MATERIALS & CONSTRUCTION TECHNOLOGY Chapter No. 1 Concrete lecture 1- concrete

2 Concrete : General definition
Concrete is a construction material obtained by mixing a cement material, coarse aggregate, fine aggregate, and in some cases admixtures. and water in a certain properties.( plain cement concrete) If steel rods are embedded in the plain cement concrete If instead of cement, lime is used as cementing material in mix, the resulting mass in termed as Reinforced cement concrete (R.C.C) Lime concrete lecture 1- concrete

3 خصائص الخرسانة الاول هو زمن الشك الابتدائي والثاني زمن الشك النهائي والثالث هو زمن التصلد - من الشك الابتدائى عن 45 دقيقةبعد صب الخرسانه اي انه يبدأ منذ اضافة الماء الى زمن ساعتين - وألا يزيد زمن الشك النهائى عن 10ساعات وذلك للأسمنت البورتلاندى العادى والأسمنت البورتلاندى سريع التصلد والأسمنت الحديدى وهو هو زمن الشك النهائي - وزمن التصلد يبدأ من 10 ساعات الى 28 يوم ماذا يحدث اذا تاخر صب الخرسانه عن اربع او خمس ساعات من زمن بدئ الخلط؟ ما دام ان الصب تم خلال فترة 4 او 5 ساعات فإن الاسمنتوالحرارة ما زالت فعالة ولم ينحرق الاسمنت صحيح ان هذا أثر على قوة الخرسانةالتصميمية فبدل ان تكون خرسانة قوة 300 ربما بعد فحصها ستجد انها 250 هذا في الظروف العادية للخرسانة لكن في حالة الخرسانة الجاهزة فيالمصانع فإنهم يضيفون مواد تزيد من طول فترة الشك الابتدائي تصل الى 4 ساعات. lecture 1- concrete

4 Concrete in architectural design
Architectural concrete masonry units are often integrally colored to enhance the appearance or achieve a particular effect. Concrete masonry units are colored by adding mineral oxide pigments to the concrete mix. lecture 1- concrete

5 Decorative Concrete lecture 1- concrete

6 lecture 1- concrete

7 Site Preparation • Uniformly grade, compact & dampen the sub-grade
• Use a 2”-3” layer of sand, gravel or stone lecture 1- concrete

8 Classification of concrete:
Mud concrete. Lime concrete Cement concrete. lecture 1- concrete

9 Point of difference between cement and lime:
Color of lime is always whitish. Color of cement is generally grey, but it can be manufactured in other desired color also. Cement when mixed with water, starts setting in a matter of minutes and acquires strength in a day or two. Lime doesn’t start setting at such a small time and it takes quit a long period before hardening. Cement is several time stronger binging material than lime. lecture 1- concrete

10 CEMENT concrete , mortars
Cement is a very important binding material, used in the construction industry. It may be natural cement or artificial cement. Natural cement: is manufactured by burning and then crushing the natural cement stones. Natural cement stones are such stones which contain the following ingredient. 20-40% of argillaceous (clay) Calcareous:(calcium carbonate-magnesium carbonate) Siloca Ammonia lecture 1- concrete

11 Artificial cement: This cement was first invented by Joseph Aspdin in The burnt mixture of calcareous and argillaceous. Alumina or clay(Al2O3):it is responsible for the setting action of the cement. Silica (Sio2): it goes in to chemical combination with calcium and silicates which are responsible for imparting strength to the cement. Lime( Cao):above 60%of the total contents, expansion disintegrationالتمدد والتفكيك lecture 1- concrete

12 4. Iron oxide: this mainly imparts color to the cement+ hardness
5. Sulphur Trioxide.ثالث اكسيد الكبريت Excess amount of it may make cement unsound. Calcium sulphate (CaSo4)or Gypsum. retard prolong the initial setting action of the cement. Magnesium Oxide(MgO).in small amount it important strength and hardness to the cement. lecture 1- concrete

13 خواص و فحوصات الأسمنت. يجرى على الاسمنت العديد من الفحوصات لتحديد صفاته وللتأكد من جودته ومطابقته للمواصفات، ومن أهم هذه الفحوصات: 1. نعومة الأسمنت Fineness of Cement 2. فحص القوام القياسي للعجينة الأسمنتية. 3. زمن الشك الابتدائي والنهائي Initial & Final setting time 4. التحليل الكيماوي للاسمنت. 5. ثبات الأسمنت . 6. مقاومة الأسمنت للضغط المباشر. 7. مقاومة الاسمنت للشد المباشر. 8. فحص الانثناء lecture 1- concrete

14 CEMENT MANUFACTURE METHODS: wet process (old) Dry process ( modern)
lecture 1- concrete

15 Concrete The Rolary Klin : A large metal cylinder its diameter near to 5m with total length 150m. rotate around its inclined axes under a temperature degree ( )OC . All the involved materials are first of all broken in crushers in size of about 2.5 cm. separately. The crushed materials are then dried with a special drought . lecture 1- concrete

16 Disadvantage of wet method
Wet , Dry Process At this method material crushed and dried then put in a rotating plate A little amount of water added to the mixture to made a hard spheres 15mm diameter These spheres heated then be interred the Rolary Klin. All remain steps completed as the wet method Disadvantage of wet method Dry process of cement manufacturing is not advocated as this process is slow, more costly and -above all, the quality of cement produced is of inferior and non-uniform quality So the dry method is more common than the wet method. lecture 1- concrete

17 Concrete TYPES OF CEMENTS
Most commonly used cement in structures is the ordinary Portland cement. But for use under specific conditions, number of special types of cements have been developed. Following are some of the cements in most common us i, under ordinary, as well as specific conditions. Ordinary Portland cement. Air Entraining Ordinary Portland cement. White and colored cement Water repellent cement. Light cement lecture 1- concrete

18 Concrete TYPES OF CEMENTS
Sulphate Resistant Portland cement. Air Entraining Sulphate Resistant Portland cement. High early strength Portland cement Air High early strength Portland cement Bacteria Resistant cement White and colored cement Water repellent cement. Light cement lecture 1- concrete

19 Concrete Water repellent cement. Quick setting cement.
Rapid hardening cement. Low heat cement. Blast furnace slag cement. High alumina cement. Pozzuolanic cement. Oil well cement. Expansive cement. Water proofing cement. lecture 1- concrete

20 Concrete LABORATORY TESTS FOR PORTLAND CEMENT
The quality of cement is verified by conducting various exhaustive tests. Following are the standard tests for cement. Chemical composition test. For this, detailed chemical analysis of cement is conducted. Chemical composition requirements of an ordinary and low heat Portland cements have been given earlier in this chapter, under heading chemical composition. lecture 1- concrete

21 Concrete LABORATORY TESTS FOR PORTLAND CEMENT
Fineness test. The high fineness means more strength ,more workability ,and more interaction The exceeded fineness cause Increases in surface area and more released reaction heat More cost of KLinker Increase the cement volume decrees. Fineness test. This test is done to verify the standard of grinding of cement. We know that rate of hydration and hydrolysis of cement, depend, upon its fineness and thus testing of the fineness of the cement is an essential feature. Fineness of cements can be determined either by sieve test or by air permeability test. lecture 1- concrete

22 Concrete LABORATORY TESTS FOR PORTLAND CEMENT
Initial Setting time test It is the time from the moment of mixing water with cement to consolidate the mixture the vicat's needle The interval between the addition of water to cement and the stage, when needle ceases to penetrate 5 mm layer of paste measured from the bottom, is known as initial setting time. of the cement. Initial setting time. of the cement. Consider as 45 minutes . lecture 1- concrete

23 Concrete LABORATORY TESTS FOR PORTLAND CEMENT
lecture 1- concrete

24 Concrete LABORATORY TESTS FOR PORTLAND CEMENT
Final setting time. The time interval between the moment water was added to cement and the moment, the stage is reached, when needle makes impression, but collar fails, is known was final setting time of the cement. This time is about 10 hours for ordinary cement. Both initial and final setting time tests are used to detect the deterioration of cement due to storage. lecture 1- concrete

25 Concrete LABORATORY TESTS FOR PORTLAND CEMENT
Compressive strength test: This test is carried out to determine the compressive strength of the cement. For this test, cement and standard sand are taken in ratio of 1:3 and a paste is prepared by adding water at the rate P/ Here P is the percentage of water required to produce a paste of standard consistency. The paste so prepared is filled in 76 mm. cube mould and vibrated on vibrating machine for 2 minutes. Twelve such cubes are molded. The freshly molded cubes are first keep in a damp cabin for 24 hrs. lecture 1- concrete

26 Concrete LABORATORY TESTS FOR PORTLAND CEMENT
Compressive strength test: and then shifted to water bath for curing. The cubes are then tested under a compression testing machine after 1, 3, 7 and 28 days of immersion. At each period interval three cubes should be tested and average compressive strength of the three should be taken as the compressive strength. The average compressive strength for ordinary, rapid hardening and low heat cements should be as given under physical properties. lecture 1- concrete

27 Concrete LABORATORY TESTS FOR PORTLAND CEMENT
lecture 1- concrete

28 Concrete LABORATORY TESTS FOR PORTLAND CEMENT
Tensile strength test. Tensile strength test. This test is carried out as follows Prepare a test cement mortar by taking cement and standard sand in ratio of 1:3 and then mixing water. The percentage of water to be mixed is determined by formula P/ , where P is the percentage of water required to produce a paste of standard consistency. Take a standard briquette and clean its internal surface properly. Small amount of grease or oil may also be applied to facilitate extrusion of the molded sample. lecture 1- concrete

29 Concrete LABORATORY TESTS FOR PORTLAND CEMENT
The mould is placed on a non-porous plate and filled with previously prepared mortar. After filling the mould some additional mortar is heaped on the mould and beaten with standard spatula, until it acquires the level of the mould and also water appears on the surface. lecture 1- concrete

30 Concrete WATER WATER Water used in mixing concrete must be clean and free of organic materials and similar materials which may react in an undesirable manner with cement or reinforcement bars as Oil ,Sault, alkaline, acids, and organic materials. On these bases, sea-water is not recommended for reinforced concrete construction. The water cement ratio is the most important single factor that affects the properties of concrete mix. Low W/C ratio results in higher strength but drier and hence less workable mix. Thus, the W\C ratio should be as low as permitted by the required workability and the available conveying and compaction means. lecture 1- concrete

31 Concrete WATER WATER Values of W\C ratio in the range of 0.5 to 0.65 are in common use. Maximum permitted concentrations of various harmful elements as suggested by I.S.I. are given below. To neutralize 200 ml of water sample it should not require more than 2 ml of 0.1 normal NaOH. To neutralize 200 ml sample, it should not require more than 10 ml of 0.1 normal HC1. lecture 1- concrete

32 Concrete WATER WATER Percentage of solids should not exceed the following percentages. Organic solids 0.02% Inorganic solids 0.30% Sulphate % Alkali chlorides 0.10% In case of any doubt, the engineer in charge may actually conduct compressive strength test on concrete. Compressive strength exhibited by concrete should not be less than 90% of the strength expected from a concrete made with the distilled water. lecture 1- concrete

33 Concrete Aggregates Aggregates generally occupy about 70% to 80% of the volume of concrete and can therefore be expected to have an important influence on its properties; aggregates provide concrete with better stability and wear resistance. Aggregate may be classified as course or fine the characteristics of course affect the mechanical properties of the concrete by affecting the mechanical bond. According to ACI code the nominal maximum size of course aggregate should not exceed 20% of the smallest dimension if the member, 33% of the thickness of the slab or 75% of the net spacing between bars. The shape and texture of the fine aggregate affects only workability. lecture 1- concrete

34 Concrete Aggregates condition to be used for or the row material of cement. aggregate , crushed or un crushed , are derived from natural sources such as river terraces and river beds , glacial deposits , rocks, boulders and gravels, for use in the production of concrete for structural purposes and mass concrete work. Aggregate surface texture are ( soft or rough , porous). The best texture is the soft texture Aggregate grade are (large ,medium, small, fine) lecture 1- concrete

35 lecture 1- concrete

36 Concrete Aggregates Categories of aggregate used in concrete are two types: Fine aggregate: Fine aggregate is the aggregate most of which passes 4.75mm IS sieve and contains no more coarse material than permitted. Natural sand is the fine aggregate which may results from natural disintegration of rock or deposited by rivers or glaciers, and there are another two types of aggregate named crushed stone sand and crushed gravel sand. lecture 1- concrete

37 Concrete Aggregates Coarse aggregate: Coarse aggregate is the aggregate most of which retained on 4.75mm IS sieve and contains no more finer material than permitted. Uncrushed gravel is the coarse aggregate which results from natural disintegration of rock, and there are other types of coarse aggregate such as crushed gravel. Because aggregate occupy 70 to 80 % of the volume of concrete and can there for be expected to have an important influence on its properties . lecture 1- concrete

38 Concrete Aggregates Coarse aggregate: Coarse aggregate is the aggregate most of which retained on 4.75mm IS sieve and contains no more finer material than permitted. Uncrushed gravel is the coarse aggregate which results from natural disintegration of rock, and there are other types of coarse aggregate such as crushed gravel. Because aggregate occupy 70 to 80 % of the volume of concrete and can there for be expected to have an important influence on its properties . lecture 1- concrete

39 Concrete TESTING OF Aggregates
Every times there are samples must be taken at various stages as : Sample at start of factory manufacture Sample when the sources change Sample when aggregate properties change. After the samples be taken there are some tests carried out as : Unit weight Voids in Agg. Resistance to degradation of coarse Agg. lecture 1- concrete

40 Concrete MANUFACURE OF CONCRETE
After testing all raw material that concrete consist and be approved ,concrete mixture designed Design of concrete mixture mean to estimate the amount of all concrete parts (water, cement, aggregate, additives ). lecture 1- concrete

41 Concrete PROPARITES OF FRESH CONCRETE
Workability This test is conducted to find out the workability of the concrete. It is performed with the help of a vessel, shaped in form of a frustum of a cone open at both the ends. Diameter. of top end is 10 cm, while it is 20 cm at the bottom end. Height of the vessel is 30 cm. 16 mm diameter and 60 cm long steel rod having pointed end is used for temping purpose. lecture 1- concrete

42 Concrete PROPARITES OF FRESH CONCRETE
workability This test is conducted to find out the workability of the concrete. It is performed with the help of a vessel, shaped in form of a frustum of a cone open at both the ends. Diameter. of top end is 10 cm, while it is 20 cm at the bottom end. Height of the vessel is 30 cm. 16 mm diameter and 60 cm long steel rod having pointed end is used for temping purpose. lecture 1- concrete

43 Concrete End lecture 1- concrete


Download ppt "Faculty of Applied Engineering and Urban Planning"

Similar presentations


Ads by Google