Subject-48352-Construction-Materials-1.docx - Subject 48352...

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Subject 48352 ConstructionMaterialsAssessment Task 2:Concrete Design ProjectJustin AVo NhatElias Do
Table of Contents1. Introduction................................................................................................................22. Mix concrete design- Fly ash/cement....................................................................33. Mix Concrete Design- Slag/Cement........................................................................64. Factors affecting concrete and their solutions....................................................85. Map pattern cracking................................................................................................86. Curing..........................................................................................................................87. Steel corrosion...........................................................................................................98. Surface spalling.........................................................................................................99. Material Specifications...........................................................................................1010. Conclusion.............................................................................................................11Bibliography.................................................................................................................12
1. IntroductionSydney metro is revolutionising an $8.3 billion public transport project in Australia andconcrete has been chosen as the construction material because it provides the good curves,appealing form, and durable robustness. This report is written to incorporate the concretemix design, curing, strength, durability and material specification.Some of the requirements are:- The characteristic compressive strength of the concrete in the precast concretesegment is 50 MPa- The mix design should have a minimum slump of 120 mm- The precast products will be steam cured
2. Mix concrete design- Fly ash/cement- The characteristic compressive strength of the concrete in the precast concrete segment is50 MPa.- The mix design has a minimum slump of 120 mm.- Temperature = 70oC (should not exceed)* Mix 1: Fly ash/ cement as a binderAccording to the data set by Teychenne, Franklin & Erntroy 1997, the large structure likemetro tunnel requires binder with Fly-ash (30%) and Low Heat Portland Cement (70%).Before deciding the mix design, the uncrushed aggregate was determined for use as thelower surface area due to the less binder required which will increase the workability andlubrication of the concrete mixture. For the structure, a maximum size of 20 mm for theaggregate is normally employed and should have a minimum slump of 120 mm. As a result,the free water content obtained from table 1 is found to be 185 kg/m3.Table 1: Approximate free-water content for various levels of workabilityTarget Mean Strength:fm= fc+ k*s = 50 + (8 X 1.64) = 63.12 MPaThe AS3600 states the value of k to be 1.64 and the value of the standard deviation is 8taking the worst scenario due to the number of tests performed were not given.Then from table 2, the approximate compressive strengths of the concrete mix that is madewith a water/cement ratio of 0.5 are used get a value of 48 MPa after 28 days since
uncrushed aggregates are considered. After that, it is plotted on graph 1 and a curve is

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Term
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Portland cement

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