Experimental Study on Previous Concrete with Various Mix Ratios

 The pervious concrete is designed with cementitious material content just enough to coat the coarse aggregate particles so that a configuration that allows the passage of water at a much higher rate than conventional concrete. The pervious concrete has many advantages that improves city environment, recharges the ground by rain water and could be used as pavement for light vehicles, pedestrian pathways, parking lots, also it reduces the tire pavement interaction noise etc. In this paper, structural property and permeability of pervious concrete made without and with different ratios of fine aggregate and pozzolan. 9.5 mm maximum size of crushed gravel and constant aggregate/cement ratio of 3.6 were used. Mix design void content is tested 20%. The specific gravity of fine aggregate 2.53 and the specific gravity of crushed stone 2.56. Type I Portland cement and waterreducing and retarding concrete admixture were used. Mix design is based on the no slump method from the American Concrete Institute’s Committee 211.3R-02, “Standard Practice for Selecting Proportions for No Slump Concrete.” This research work was divided into third/three sections. The first section is without pozzolan and fine aggregate and second section is with two different ratios of pozzolan third section is without pozzolan and with fine aggregate. Pozzolan is used as a supplementary cementitious material to partially replace Portland cement in pervious concrete mixes up to 20% by weight. Fine aggregate partially replace as a coarse aggregate in pervious concrete mixes up to 10% by weight. Mix design void content is tested 20%. This concrete is tested for its properties, such as density, void content, compressive strength and water permeability. The most important property of pervious concrete is its water permeability. Keywords Pervious Concrete, Pozzolan, Fine Aggregate, Density, Void Content, Compressive Strength, and Permeability


I. INTRODUCTION 1
Pervi ous concrete is a composite material consisting of coarse aggregate, Portland cement and water.It is different from conventional concrete as the mixture contains no fines in it.The aggregate is usually of a single size and is bonded together by a cement paste.The result is a concrete with a high percentage of interconnected voids that allow the penetration of water through the material matrix.Normal concrete has a void ratio around 3-5% and pervious concrete has higher void ratios from 18-40% depending on its application.Pervious concrete differs from normal concrete in several other ways.Pervious concrete has lower compressive strength, higher permeability and a lower density.Its compressive strength could be 65% lower than the normal concrete [1].Pervious concrete is increasingly being installed to improve stormwater quality and reduce runoff produced by urban settings.During the last few years, pervious concrete has attracted more and more attention in concrete industry due to the increased awareness of environmental protection.The focus of pervious concrete technology is the balance of permeability and mechanical properties as well as durability.Pervious concrete shows in Figure 1.If the mixture is too wet and easy to compact, the voids will be clogged and the permeability will be compromised.If the mixture is too dry and hard for compaction, the pervious concrete pavement will be weak and vulnerable to various types of distress [2].A concrete mix design can be proportioned from existing statistical data using the same materials, proportions, and concreting conditions.The one that will be described in this study is based on the no slump method from the American Concrete Institute's Committee 211.3R-02, "Standard Practice for Selecting Proportions for No Slump Concrete."[3] The mixture proportions used in this study is listed in Table 1.Pervious concrete mixtures require a careful analysis of aggregate properties for a structure which has adequate strength and allowing water to drain through its matrix.Four different pervious concrete mixes have been prepared in this research: Mix 1(0% pozzolan, 0% fine aggregate), Mix 2 (10% pozzolan, 0% fine aggregate), Mix 3 (20% pozzolan, 0% fine aggregate) and Mix 4(0% pozzolan,10% fine aggregate).For all four mixes, the water to binder materials (cement plus pozzolan) ratio was maintained at 0.27 and coarse aggregate to binder materials ratio (cement plus pozzolan) was maintained at 3.6.In this research, desired slump value is zero.This test is performed as ASTM 143 procedure.Testing of slump is shown in Figure 3.The details of the chemical composition of Portland cement and pozzolan are listed in Tables 2 and 3.

B. Experimental Program A. Experimental Program
Fresh concrete mixes were produced in a pan-type of concrete mixer.The fresh density of pervious concrete was tested from ASTM C1688 Fresh density test is shown in Figure 4.The compressive strength was carried out in accordance with the test procedures given in ASTM C39, and the average compressive strength of results obtained with two identical specimens are reported.The standard compressive strength tests were performed on the cubes (150 mm x 150 mm x 150 mm).The compressive machine for test cubes is hydraulic compression testing machine is shown in Figure 5.
The void content was determined in accordance with ASTM C1754 by taking the difference in weights of an oven dried specimen, and when submerged in water, The Third International Conference on Civil Engineering Research (ICCER) August 1 st -2 nd 2017, Surabaya -Indonesia using Equation 1. Hardened void content is shown in Figure 6.The water permeability was calculated based on Darcy's Law, given below: Where, l is the length of the specimen, A 1 is the cross sectional area of specimen and A 2 is cross sectional area of drain pipe and K is the coefficient of permeability.
The valve is then opened, and the time taken (in seconds, t) for the water to fall from the initial head to a final head (h 1 to h 2 ).The cast test specimens were demoulded after 24 hours and stored in water at 20˚C until the age of testing.The water permeability of pervious concrete was determined using a procedure described [4].Water permeability test is shown in Figure 7.The absorption was determined in accordance with IS 2386.The absorption test is shown in Figure 8.The (150mm x150mm x150mm) Cubes after casting will be immersed in water for 28 days curing.These specimens will then oven dried for 24 hours at the temperature 110°C until the mass became constant and again weighed.This weight was noted as the dry weight (W 1 ) of the block.After that the specimen will be kept in hot water at 85°C for 3.5 hours.Then this weight will noted as the wet weight (W 2 ) of the block.After crushing that specimen will noted as the wet weight (W 3 ) of the block., total 120 cubes (60 cubes for each mix) are cast to allow the compressive strength to be monitored at 28 days.Figure 13 shows durability of pervious concrete test results.For compressive strength, total 60 cubes (15 cubes for each mix) are cast to allow the mean compressive strength  ,  ′ to be monitored at 7 days, 28 days, 56 days, 90 days and 180 days respectively.The density of pervious concrete without fine aggregate decreased marginally when the cement is partially replaced with pozzolan.The density values were 1827.18,1807.08 and 1785.15kg/m3 when 0 %, 10 % and 20 % of cement was replaced with pozzolan, respectively.The density of pervious concrete without pozzolan was marginally increased by adding fine aggregate.The density of pervious concrete without pozzolan and with 10 % fine aggregate was 1845.01 kg/m3.The void content and water permeability of pervious concrete were marginally reduced when the fine aggregate content and pozzolan content were increased.The compressive strength of pervious concrete without fine aggregate increased marginally when the cement is partially replaced with pozzolan 10% but 20% pozzolan marginally decreased.The compressive strength values were 18.49, 21.39 and 14.51 MPa when 0%, 10 % and 20 % of cement was replaced with pozzolan, respectively.The compressive strength of pervious concrete was influenced when increasing the fine aggregate content.The compressive strength value was 23.21 MPa.Pervious concrete without pozzolan and fine aggregate is the best performed in water permeability.Pervious concrete with 10 % fine aggregate will improve compressive strength but at the same time permeability will be reduced.Durability of pervious concrete, the compressive strengths develop with age for all four mixes of pervious concrete.After 28days, strength develops slowly.

IV.CONCLUSION
Due to voids in pervious concrete, it is difficult to obtain high-strength by using the common material and proportion of mixture.Replacement of 10% pozzolan in cement will improve the compressive strength and workability but at the same time permeability will be reduced.It can be seen that replacement of pozzolan in cement should not be more than 10%.The pervious concrete made without fine aggregate and pozzolan performed best in water permeability and workability.The compressive strength of pervious concrete without pozzolan will significantly increase with the addition of fine aggregate but at the same time permeability and workability will be reduced.The partial replacement of the fine aggregate content in coarse aggregate should not be more than 10%.More than that will reduce the permeability also which are the major properties of pervious concrete.Replacement of 10% fine aggregate in coarse aggregate should not be used rainfalls area.Pervious concrete has high water permeability due the presence of interconnected air voids.So, pervious concrete should be used Yangon flooded area such as pavement edge drains, low water crossings area, path ways and shoulder.It can be concluded that pervious concrete with good characteristics can be produced by partially replacing cement with pozzolanic material.This leads to multiple advantages such as improving pervious concrete, reducing production cost and also decreasing the carbon dioxide emission due to the reduction in amount of cement.

Figure 3 .
Figure 3. Slump Test of Concrete

Figure 5 .
Figure 5. Compressive Strength Test (a) Place in Oven (110 Ċ) (b) Concrete cube (c) Submersed Wt. Figure 6.Hardened Void Content TestThe void content was determined in accordance with ASTM C1754 by taking the difference in weights of an oven dried specimen, and when submerged in water, using Equation1.Hardened void content is shown in Figure6.  = [ − {   −  /   × : }] × Eqn.(1) Where, V r = Void content M w = weight under water M d = oven dry weight vol: = volume of sample, and  w = density of water

Figure 9 .
Figure 8. Absorption Test of Pervious Concrete III.RESULTS AND DISCUSSION Figure 9 for Mix1, Figure 10 for Mix 2, Figure 11 for Mix 3 and Figure 12 for Mix 4 show comparison of The Third International Conference on Civil Engineering Research (ICCER) August 1 st -2 nd 2017, Surabaya -Indonesia conforming to (ASTM 618) in Figure 2. The specific gravity of Portland cement is 3.08.Fineness of cement is 5.6%.The specific gravity of Popa pozzolan is 2.77.Fineness of Pozzolan is 4.9%.2. 4.75 mm to 9.5 mm crushed gravel, which is nominal-size, was used as coarse aggregate.The specific gravity of crushed gravel is 2.56 and unit weight is 1482.65 kg/m 3 .The absorption of crushed gravel is 0.79%.Abrasion value of crushed gravel is 30.90 %. 3. River sand with specific gravity 2.53 and fineness modulus 2.7 from Hlaing river in Yangon is used as fine aggregate.The unit weight of fine aggregate is 1773.93kg/m 3 .

Table 2 .
The Third International Conference on Civil Engineering Research (ICCER) August 1 st -2 nd 2017, Surabaya -Indonesia Chemical Composition of Cement

Table 4 .
Comparison of Pervious Concrete (With or Without Pozzolan) and (With or Without Fine Aggregate)