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AN EXPERIMENTAL STUDY ON PROPERTIES AND BEHAVIOR OF HIGH STRENGTH CONCRETE AND REACTIVE POWDER CONCRETE

Guided By: Dr. Samaiya Nitin Kumar Mr. Krishna Murari Presented By: Udit Jain Vikram Rajvanshi

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HIGH STRENGTH CONCRETE In many places in USA, High Strength Concrete is defined as minimum of 40 MPa or strength higher than the usual level in this region.

According to IS 456:2000, HSC is concrete with compressive strength greater than 60 MPa Ingredients of High Strength Concrete (HSC):Cement, aggregates, water are the usual ingredients of concrete.Additionally, for high strength concrete the following are requiredSilica FumeSuperplasticizerFly ash, Granulated Slag optionalFiber reinforcement optional

Bandra Worli Sea LinkM60 grade high performance concrete was designed for the construction of the superstructure in the Bandra - Worli Sea Link in Mumbai.Target 28 day compressive strength 74N/mm2Cement 330 kgSilica Fume-33 kgCoarse aggregate 1028 kgFine aggregate 1026 kgWater 130.68 kg (w/c =0.34)Superplasticiser 10 kg(*All quantities per m3 of concrete)Slump 120 mm

Delhi Metro Rail CorporationDMRC also designed M60 grade of HSC for the construction of the piers and the deck of the span. Their ratio is as follows:Target 28 day compressive strength 72N/mm2Cement 475 kgSilica Fume-35 kgCoarse aggregate 1255 kgFine aggregate 484 kgStone Dust 54 kgWater 147 kg (w/c =0.30)Superplasticizer 7.14 kg(*All quantities per m3 of concrete)

REACTIVE POWDER CONCRETE

The materials that form Reactive Powder Concrete are: Steel Fibers (Aspect Ratio 72) Quartz Sand 400 to 200 Microns Silica Fume or Micro silica Ordinary Portland Cement (OPC) Acrylic or PCE based super plasticizer WaterReactive Powder Concrete (RPC) or the patented name Ductal was developed by a combined effort of three companies working in France: Bouygues, a contracting company, Lafarge, a manufacturer of construction materials and Rhodia, a manufacturer of chemical materials. Applications with Ductal use less material; are lighter in weight; more elegant; easier, faster, and safer to construct; lower in maintenance; and have a longer life than conventional materials.

Compressive strength is expected to be around 200 Mpa.

Sherbrooke Pedestrian Bridge in Canada Footbridge of Peace in South KoreaThe Sakata Mirai bridge in JapanPRACTICAL APPLICATIONS OF RPC

EXPERIMENTAL PROGRAM

HIGH STRENGTH CONCRETE

High Strength Concrete (HSC) mix was designed by varying certain quantities to study their effect on strength. The materials used for preparing High Strength Concrete are:

MATERIAL

OPC Grade 43OPC Grade 53Fine AggregateType 1 Coarse AggregateType 2 Coarse AggregateSilica Fume Grade 920DSuperplasticizer BASF, PCE BasedWater

PROPERTYT1 AggregateT2 AggregateSpecific Gravity2.722.75Water Absorption1.601.45Crushing Value27%17%COARSE AGGREGATE

Two different type of coarse aggregate was used in the project. Locally available crushed aggregate, Type 1 (T1) Omkareshwar crushed aggregate, Type 2 (T2). Crushing Value of T2 was much better than T1 aggregate.

HSC MIXHSC 1HSC 2HSC 3HSC 4HSC 5HSC 6Materialskg/m3kg/m3kg/m3kg/m3kg/m3kg/m3Cement450450425400400350Silica fume 323230282824.5Fine Aggregate763755763663655814.32Coarse Aggregate114411311144114411311221.48Superplasticizer 6.756.754.25867Water111133137121.44145.2186.135Water/binder ratio0.230.2750.300.230.2750.23MIX PROPORTIONS USED FOR HSCHSC MIXHSC 7HSC 8HSC 9HSC 10HSC 11Materialskg/m3kg/m3kg/m3kg/m3kg/m3Cement450450450450450Silica fume 3232323232Fine Aggregate763763763763763Coarse Aggregate11441144114411441144Superplasticizer 86.75654.5Water96.4108.45120.5132.55144.6Water/binder ratio0.20.2250.250.2750.3

MIX PROPORTIONS USED FOR RPCMaterials (kg/m3)Batch 1Batch 1Batch 1Batch 1Ordinary Portland cement 934955600955Silica fume 234230145230Fine sand (150-400 microns)103011006921100Coarse Aggregate008500Superplasticizer 12.76038Trial & ErrorSteel fibres0000Water215210160210Water/binder ratio0.180.180.190.18Materials (kg/m3)Batch 5Batch 6Batch 7Batch 8Materialskg/m3kg/m3Kg/m3kg/m3Ordinary Portland cement 955955955955Silica fume 230230230230Fine Aggregate1100110011001100Coarse Aggregate0000Poly Propylene Fibers9.55 0 04.775Superplasticizer 76656060Water210219210210Water/binder ratio0.180.180.180.18

The materials of RPC Batch 1 to Batch 4 were hand mixed due to unavailability of a high speed mixer. Proper mixing of such fine material is by hand mixing is not possible, and even the water content for RPC is very low. So, the desired results were not obtained. Polypropylene fiber was used in Batch 5 and Batch 8, and all mixing was done using the high speed mixer. The mix formed now was far better than previous batches. It was still not as it was desired. The mixing has to be so quick and swift that RPC becomes a flowing concrete. It was still not possible to get that kind of a mix without the high speed mortar mixer or pan mixer.

High Speed Mixer RPC without PPF RPC with PPF

MaterialsBATCH 9BATCH 10Ordinary Portland cement934 (OPC 43)934 (OPC 53)Silica fume 234234Quartz Sand10301030Coarse Aggregate00Superplasticizer 6060Steel fibers187187Water215215Water/binder ratio0.180.18RPC Batch 9 and Batch 10

In Batch 9, steel fibers were arranged and added to the mix.

In Batch 9 of RPC, 5 sets of cubes were casted:

Set 1: Autoclave curing at 210C and 2 MPa pressure was done for 8 hours (9). Set 2: Autoclave curing at 210C and 2 MPa pressure was done for 8 hours and then the cubes were kept at 27C for 28 days. Set 3: Ordinary 28 days curing was done at normal temperature. Set 4: In the fourth set, an external pressure was applied on the cubes immediately after casting (9). Curing was done at normal temperature for 28 days. Set 5: External pressure with 56 Days curing.

RPC Batch 9 in Bitumen Mixer

RPC Batch 9 after Mixing`

RESULTS & ANALYSISREACTIVE POWER CONCRETE

BATCH 1 to BATCH 4:

Mix formed was very dry.Weight of the cubes was less than expected.Excessive Air bubbles emerged from the cubes when kept in curing tank.Silica Fume and Quartz Sand were distinctly visible when the cube was broken.Expected strength was not achieved.

The materials of RPC Batch 1 to Batch 4 were hand mixed due to unavailability of a high speed mixer. Proper mixing of such fine material is by hand mixing is not possible. Due to improper mixing, the materials could not blend with each other to form a homogenous mix and the desired results were not obtained.

RPC BATCH 5, BATCH 6, BATCH 7, & BATCH 8

The 28 Days compressive strength of RPC batches 5 to 8 are shown in the graph below:

Batch 8 with Polypropylene fibers showed the maximum strength from Batch 1 to Batch 8.

RPC BATCH 9

In Batch 9 of RPC, Steel Fibers were used and 5 sets of cubes were casted:

RPC Batch 9 Cube after Failure-1

Even after the failure load RPC cubes did not break like a brittle material. Though the cubes had taken the failure load, no major cracks were visible. The shape of the cubes was still intact. RPC Batch 9 Cube after Failure-2

RPC BATCH 10

In Batch10, OPC 53 Cement was used for making RPC. Here 3 sets of cubes were casted:

RESULTS & ANALYSIS HIGH STRENGTH CONCRETE

Five variables were taken to study their effect on the compressive strength of High strength concrete:

Cement quantity was varied. Cement grade was varied. Coarse aggregate was varied. Water/Binder ratio was varied. External Pressure was applied in some cases Variation in Cement QuantityIn the ratios HSC 1 to HSC 6, the quantity of cement used has been decreased constantly from 450 kg/m3 to 350 kg/m3. The compressive strengths of HSC 1 to HSC 6 are shown below:

Variation In Cement Grade

Two type of cement grades were used to see the change in the strength property when grade was varied. The results due to change in grade of cement after 28 Days of curing are shown here.The results in Compressive Strength due to change in grade of cement after 56 Days of curing are shown here.

Variation In Coarse Aggregate

In high strength concrete, failure usually takes place due to cracking of coarse aggregate; not due to cracking of cement mortar. If better quality of coarse aggregate is used in preparing High strength concrete, much higher strength can be achieved. Two different type of coarse aggregate was used in the project. Locally available crushed aggregate (T1) Omkareshwar crushed aggregate (T2). Crack in Coarse AggregateVariation In Water-Binder Ratio

Water/binder ratio is one of the major factors that affect the strength of concrete. It is known that as the water-binder ratio decreases, the strength of concrete increases. The effect of w/b ratio on high strength concrete was studied and same kind of relation was seen.HSC With External PressureAn external load of 20 to 30kN is applied to fresh concrete and it gets compacted further. This process helps in better compaction and ultimately better strength of concrete.

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