Civil Engineer

  प्रबलित सीमेंट कंक्रीट के लाभ या गुण  1. प्रबलित कंक्रीट की अंतिम लागत मितव्ययी  होती है। 2. इस्पात व् कंक्रीट का रेखीय प्रसार गुणाँक  लगभग समान होती है, जिसके कारण प्रबलित सीमेंट कंक्रीट के अखण्ड पदार्थ के गुण होने के कारण संरचना की स्थिरता बढ़  जाती है। 3. कंक्रीट किसी भी आकृति में सुगमता से ढाली जा सकती है तथा इसके अवयव सरलता से प्रत्येक स्थान पर उपलब्ध हो जाते है। 4.  इसकी स्थिरता अधिक होती है तथा अन्य निर्माण सामग्री की अपेक्षा अधिक अग्निरोधक होती है। 5. प्रबलित कंक्रीट पर दीमक व् ऐसे ही अन्य किसी भी प्रकार के हानिकारक जीवाणुओं का कोई  प्रभाव  नहीं होता। 6. इसकी देखभाल व् अनुरक्षण  लगत लगभग नगण्य होती है। 7. इसकी निर्माण लागत भी अपेक्षा कृत काम ही होती है।  www.EveryOneEngineer.com A Good Quality Construction is a Result of Good Knowledge. Keep Learning....Keep Growing.... Thank You, Have a Nice Day,

DURABILITY OF CONCRETE Introduction- A durable concrete is one that performs satisfactorily in the working environment during its anticipated exposure conditions during service. The materials and mix proportions specified and used should be such as to maintain its integrity and, if applicable, to protect embedded metal from corrosion. 1. One of the main characteristics influencing the durability of concrete is its permeability to the ingress of water, oxygen, carbon dioxide. chloride, sulphate and other potentially deleterious substances. Impermeability is governed by the constituents and workmanship used in making the concrete. With normal-weight aggregates a suitably low permeability is achieved by having an adequate cement content sufficiently low free water/ cement ratio, by ensuring complete compaction of the concrete. and by adequate curing.  The factors influencing durability include: a) the environment; b) the cover to embedded steel;  c) the type and quality o

Requirements for Durability Of Concrete  Shape and Size of Member  The shape or design details of exposed structures should be such as to promote good drainage of water and to avoid standing pools and rundown of water. Care should also be taken to minimize any cracks that may collect or transmit water. Adequate curing is essential to avoid the harmful effects of early loss of moisture . Member profiles and their intersections with other members shall be designed and detailed in a way to ensure easy flow of concrete and proper compaction during concreting.  Concrete is more vulnerable to deterioration due to chemical or climatic attack when it is in thin sections, in sections under hydrostatic pressure from one side only, in partially immersed sections and At corners and edges of elements. The life of the structure can be lengthened by providing extra cover to steel, by chamfering the corners or by using circular cross sections or by using surface coatings which prevent or redu

S.No. Environment Exposure Condition A B C 1. Mild 1.        Concrete surface protected against weather or aggressive conditions, except those situated in coastal area. 2. Moderate 1.        Concrete surface sheltered from severe rain or freezing whilst wet, 2.        Concrete exposed to condensation and rain, 3.        Concrete continuously under water, 4.        Concrete in contact or buried under non-aggressive soil/ground water, 5.        Concrete surface sheltered from saturated salt air in coastal area. 3. Severe 1.        Concrete surface exposed to severe rain, alternate wetting and drying or occasional freezing whilst wet or severe condensation. 2.        Concrete completely immersed in sea water, 3.        Concrete exposed to coastal environment 4. Very Severe

Relation Between Entrained Air Percentage And Nominal Maximum Size of Aggregate (Freezing and thawing of concrete) as per Indian Standard S.No. Nominal Maximum Size Of Aggregate Entrained Air Percentage (mm) (%) a b C 1 20 5±1 2 40 4±1 www.EveryOneEngineer.com A Good Quality Construction is a Result of Good Knowledge. Keep Learning....Keep Growing.... Thank You, Have a Nice Day,

  Requirement of Concrete Cover   A). The protection of the steel in concrete against corrosion depends upon an adequate thickness of good quality concrete.  b).  The nominal cover to the reinforcement shall be provided as per Indian Standard 456:2000 (26.4) www.EveryOneEngineer.com A Good Quality Construction is a Result of Good Knowledge. Keep Learning....Keep Growing.... Thank You, Have a Nice Day,

Concrete Mix Proportions  A) General The free water-cement ratio is an important factor in governing the durability of concrete and should always be the lowest value. Appropriate values for minimum cement content and the maximum free water-cement ratio are given in Table 5 for different exposure conditions. The minimum cement content and maximum water-cement ratio apply to 20 mm nominal maximum size aggregate. For other sizes of aggregate they should be changed as given in Table 6. S.No. Exposure Plain Concrete Reinforced Concrete     Minimum Cement Content Maximum Free Water-Cement Ratio Minimum Grade of Concrete Minimum Cement Content Maximum Free Water-Cement Ratio Minimum Grade of Concrete     Kg/cum     Kg/cum     a b c d e