Eco-Friendly Concrete Mix Design with Industrial Wastes by Perceptive of Constituents Chemistry

By D. S. Rajendra Prasad¹ *, S. Suresh², G. S. Shashidhar²
August 2012

The authors lecture at the Department of Civil Engineering, Siddaganga Institute of Technology (SIT), Tumkur, Karnataka, India

  1. Professor *Corresponding Author
  2. Research Scholar
Abstract
This paper presents the experimental study undertaken to investigate the influence of partial replacement of sand with Crushed Rock Powder (CRP), and cement with fly ash and Rice husk Ash on the concrete compressive strength development subjected to different water, carbon dioxide and air curing periods by better understanding of chemistry of constituents of the concrete mix. The use of byproducts is an environmental friendly method of disposal of large quantities of materials that would otherwise pollute land, water and air. This study focuses on utilization of waste Pozzuolana products such as fly ash and Rice Husk Ash (RHA) as partial replacement to OPC to produce blended concrete with an objective to increase the optimum percentage of replacement of pozzuolana to OPC without affecting the concrete properties. Carbon dioxide (CO2) is produced in huge quantity which is left into atmosphere affecting it. Therefore it can be captured, stored and used for curing of concrete in pre-cast concrete plants where plants uses reusable moulds to form panels, walls, beams, columns etc., that are cured in the plant and then shifted to construction site, offering faster production over water curing on site.

Keywords: Crushed Rock Powder (CRP), Carbon Dioxide Curing (CC), Water Curing (WC), Rice Husk Ash Concrete (RHC), Fly Ash Concrete (FHC), Air Curing (AC).

Introduction

In recent years, remarkable efforts have been taken in the domain of concrete engineering and technology to research and study the utilization of by-products and waste materials in the production of concrete. The successful utilization of these materials will result in the reduction of global warming and environmental loading, waste management cost and concrete production cost, besides enhancing the properties of concrete in both fresh and hardened state. Efforts in this direction have been focused in identifying and optimizing the benefits of different types of cement replacement materials as well as identifying alternative materials as aggregates in concrete and by better perceptive of constituents chemistry of the concrete mix.

Prachoom Khamput¹, studied the compressive strength of concrete using quarry dust as fine aggregate instead of sand. Ratio of cement : sand : rock is 1 : 2 : 4 (by weight) and at water-cement ratio (w/c) of 0.45. The paper published by Raman S. N², reports the experimental study undertaken to investigate some properties of quarry dust and discusses the suitability of those properties to enable quarry dust to be used as partial replacement material for sand in concrete. Ilangovana R³ and Chaturanga Lakshani Kapugamage4, studied the feasibility of the usage of Quarry Rock Dust as hundred percent substitutes for Natural Sand in concrete. It is found that the compressive, flexural strength and Durability Studies of concrete made of Quarry Rock Dust are nearly 10% more than the conventional concrete. Alireza Naji Givi5, presents an overview of the work carried out on the use of RHA as partial replacement of cement in mortar and concrete. Habeeb G.A6. and Muhammad Harunur Rashid7, conducted an experimental investigation on the influence of Rice Husk Ash (RHA). Average Particle Size (APS) on the mechanical properties and drying shrinkage of the produced RHA blended concrete. Dao Van Dong8, presents several key properties of high strength concrete using rice husk ashes (RHAs). Mauro M. Tashima9  and Shao Y10, evaluates how different contents of rice husk ash (RHA) added to concrete may influence its physical and mechanical properties.

The recent development in the field of concrete technology represents a giant step towards making concrete a high-tech material with enhanced characteristics. Some alternative materials already have been used as a part of natural river sand. For example, Fly ash, slag and lime stone, granite powder were used in concrete mixture as a partial replacement of natural sand. In present work, quarry rock dust is used as a sand replacement material. Crushed Rock Powder (Rock dust/ quarry dust) is a by-product generated from quarrying activities involved in the production of crushed coarse aggregate. When the quarry dust is observed with edges, their size is very close to sand. Thus the quarry dust may be examined the physical properties by using the standard of fine aggregate. Hence Crushed Rock Powder is used as an alternative of natural sand and its effects on the compressive strength of the different levels of CRP concretes were investigated. Felixkala T11 studied the properties of HPC with granite powder as fine aggregate. The test results show clearly that granite powder of marginal quantity as partial sand replacement has beneficial effect on concrete properties.

In Greece, a recent report by Papadakis12 has revealed that although about 10 million tons of fly ash is generated annually, their absorption in several applications (mainly the cement industry) is stuck at 10%. The amounts that remain unused obviously create acute environmental problems and moreover inhibit the path towards sustainability. For increasing the utilization rate of this by-product, it is necessary to fully explore its dynamic and pozzolanic potential, but also to come up with methods of enhancing its slow reaction. This task however becomes difficult when dealing with a very heterogeneous product, where not all streams are the same, chemically or physically, and furthermore, when the effect of each of those parameters on the hydration of fly ash/cement (FC) systems has not yet been completely understood. Raman13, reports the experimental study undertaken to investigate the influence of partial replacement of sand with quarry dust, and cement with fly ash on the concrete compressive strength development. Two types of replacement proportion of sand with quarry dust, 20% and 40% were practiced in the concrete mixes except in the control concrete mix. Besides, replacement proportion of 10% cement content with fly ash was practiced in some of the concrete mixes. Two types of curing methods, water curing and air curing under controlled laboratory conditions were practiced during the entire study. Recorded results indicate that concrete incorporating quarry dust without the inclusion of fly ash exhibited lower compressive strength than the control concrete at all ages. This weakness was overcome by the inclusion of fly ash into the quarry dust concrete in which it resulted in the enhanced compressive strength at almost all conditions. It can be concluded that quarry dust can be utilized as partial replacement material to sand, in the presence of fly ash, to produce concretes with fair ranges of compressive strength. Satakhun Detphan14, presents the fundamental data of fly ash based geopolymer mixed with the open-field rice husk ash, the basic properties viz., setting time, burning temperature of rice husk heap, temperature and pH during mixing were presented, furthermore, the 7 days strength of geopolymer mortar replaced by rice husk ash of 0, 20, 40 and 60% were also investigated. Gambhir15 investigated the contribution of fly ash (FH) to the positive effects in the strength in concrete has been attributed to direct water reduction, the increase in the effective volume of paste in the mix and its pozzolanic reaction . Its pozzolanic activity is due to the presence of finely divided glassy silica and lime which produce calcium silicate hydrate as is produced in Portland cement. Naidu16 investigated the influence of partial replacement of sand with quarry dust and cement with mineral admixtures on the compressive strength and pull-out force of concrete, whereas Celik and Marar17 investigated the influence of partial replacement of fine aggregate with crushed stone dust at varying percentages in the properties of fresh and hardened concrete.

Rice milling generates a by product known as husk. This husk is used as fuel in the rice mills to generate steam for the boiling process. This husk contains about 75% organic volatile matter and the balance 25% of the weight of this husk is converted into ash during the firing process, is known as rice husk ash (RHA). This RHA in turn contains around 85% - 90% amorphous silica. In present work 10% RHA is used as cement replacement material.

Carbon dioxide emissions are one of the most serious concerns among all greenhouse gas emissions. Carbon dioxide emissions can be affected by combustion of organic materials (e.g., wood, coal, oil and other fuels), or by human and animal metabolism (respiration) in which oxygen is utilized and CO2 is given off as an end product. Also, dead animals, plants and other organic matter generate CO2. Oil or coal burning power plants and cement-producing industries account for a large amount of CO2 emissions. According to the statistics of the year 1998, 3.1% of the total CO2 emissions were from the cement manufacturing industry (World Resource Institute). Approximately 88% of the CO2 emitted and concrete industries is produced by cement production,1% is produced by concrete production, 9% by its use in construction, and 3% by demolition and waste handling. There exists an urgent need for a reduction in CO2 emissions and/or recycling of CO2. An effective method for the reduction of CO2 in the environment is to store carbon dioxide librated from various industries and use that for curing of concrete. Chun Y.M.18, summarizes the results of an investigation on carbon dioxide (CO2) sequestration in concrete. Kauer19 were cured the fresh concrete specimens in various humidities and temperatures in CO2  atmospheres ranging from 4.5 to 18% for 24 to 96hr. concrete. Shao10 were investigated the feasibility of recycling carbon dioxide into concretes through their curing processes. Owens K J20, has investigated the utilization of carbon dioxide from flue gases to improve physical and micro structural properties of cement and concrete systems.

Materials Used

Cement

Ordinary Portland cement of 53-grade was used in this study conforming to IS: 12269-1987. The physical properties are: Specific gravity = 3.15; Normal consistency = 28.3%.

Constituent % Composition
Fe2O3 0.95
SiO2 67.30
CaO 1.36
Al2O3 4.90
MgO 1.81
L.O.I 17.78

Fly ash

Specific gravity of fly ash is 2.2 as per Specific gravity Test IS: 2386 (Part III) 1963.

RHA

RHA from the rice mill was used.10% RHA was considered in the present study as a replacement of cement. The specific gravity of RHA used is 2.0. The chemical composition of rice husk ash is shown on the right.

Fine Aggregate

The concrete mixes were prepared using river sand and CRP. The percentage of CRP by weight ranging from 0 to 100% as a replacement of sand was used in concrete. CRP is obtained from the nearby crusher units in Tumkur, Karnataka, India. Fineness modulus and specific gravity of the CRP are 2.78 and 2.63 respectively. Locally available river sand was also adopted to prepare reference mix for comparison purpose. Fineness modulus and specific gravity of sand are 2.9 and 2.64 respectively. The amount of fine particles present in CRP is considerably higher when compared to the river sand.

Coarse Aggregate

The blue metal was used as a coarse aggregate. Their specific gravity and water absorption are 2.67 and 0.4 % respectively. The tests were conducted as per IS: 383 – 197021.

Water

In general, water fit for drinking is suitable for mixing concrete. Impurities in the water may affect concrete setting time and strength. Hence locally available purified drinking water was used in the present work.

Sambrani (Benzoin resin)

Sambrani is one of the oldest incense. It is a balanced resinaceous mixture of several elements derived from tropical wood, barks, roots, and resins. It is well used in Indian temples for worship.

Sambrani is burnt and the gas was collected in a standard flask to get solution. The solution is analyzed for its chemical composition. The major components are:

Cement and Pozzolanic Reaction

If a concrete contains pozzolans like Fly ash and Rice husk ash, less cement is required to obtain a specified strength. A highly reactive pozzolan has more cementitious strength than a lower reactive pozzolan. Edwin R22 presents the pozzolanic reaction as follows:

Siliceous pozzolanic materials and lime reactions
3 [Ca(OH)2] + 2 [SiO2] = 3 (CaO) 2 (SiO2) 3 (H2O)
222 + 120 = 342

In this reaction 222 parts of lime reacts with 120 parts silica for a mass ratio of 222/10=1.85. If a pozzolan is only 25% reactive and is combine with 0.46(%) of lime the reactive portion ratio is 0.46/0.25 = 1.4.

Aluminous pozzolanic materials and lime reactions
3 [Ca(OH)2] + AL2O3 + 3 [H2O] = 3 (CaO) AL2O3 6 (H2O)
222 + 102 + 54 = 378

The relationship between lime and alumina is 222/102 = 2.18. Alumina combines with more lime than does silica.

Kauer19, presents the carbonation in cement-based products can be defined as a reaction between the CO2 dissolved in water and the cement hydration product Ca (OH)2 in the pore water. Since the gas is dissolved in water, the CO2 is may be in the form of H2CO3, which in turn could react with the calcium ions of the pore water. The type of carbonate ions depends on the pH of the hydrated cement paste. When CO2 comes in contact with water at neutrality it forms bicarbonate. Inside concrete the pH is high and the bicarbonate dissociates and forms carbonate ions. Thus in the carbonated layer bicarbonate forms (due to low pH) but closer to the uncarbonated cement paste. This carbonate ion forms and precipitates calcium carbonate crystals (CaCO3).

Calcium carbonate exists in three crystallographic forms, viz. aragonite, vaterite and calcite. Calcite and vaterite are commonly found in carbonated concrete. Presumably the metastable vaterite will transform to stable calcite with time. These reactions can be expressed by equations (1) and (2).

CO2 (g) + H2O = HCO3-(bicarbonate ion) + H+ (1)

HCO3- = CO32-(carbonate ion) + H+ (2)

The carbonate ion will react with calcium ions in the pore solution to form calcium carbonate (Eq. 3).

Ca2+ + CO32- = CaCO3 (3)

This will lead to lower concentration of Ca2+, which in turn will lead to dissolution of calcium hydroxide (CH). The solubility of calcium carbonate (CC) is much lower than that of CH.

Ca(OH)2 = Ca 2+ + 2 OH- (solubility 9.95 x 10-4) (4)

Ca2+ + CO32- = CaCO3 (solubility 0.99 x 10 -8) (5)

Thus CH dissolves and CaCO3 precipitates and the process continues until all of the CH is consumed. Apart from CH the cement paste contains calcium silicate hydrate (C-S-H) and ettringite/monosulphate (AFt/AFm). All these phases are stabilized by high pH and Ca ions. Thus when the CH is consumed the C-S-H dissolves congruently. The percentage of above gases may vary with the brands. Darker the sambrani stick; higher is the percentage of CO2 present in it.

Experimentation

Concrete Mix Proportions

M30 grade concrete mixes of different CRP levels and Fly ash levels (10% to 50% replacement of cement) and RHA of 10% with w/c ratio of 0.45 were prepared. The mixes were designated in accordance with IS: 10262-200923 and SP: 23-1982. The details of mix proportions with various curing methods are given in Table 1.

Specimen Preparation

Figure 1 · Cubes before 6 hr CO2 curing
Figure 1
Figure 2 · Cubes during & after 6 hr CO2 curing
Figure 1

The CRP was collected from local crusher units and Fly ash was collected from UltraTech Ready Mix Plant. Its properties were tested in the laboratory. The Fly ash, rice husk ash and cement were first dry mixed in a pan thoroughly so that a uniform mix of rice husk ash and cement is obtained. Fine and coarse aggregates were added together in the mixer. Then one third of the water is added. The mixture of rice husk ash and cement was then added into the mixer. The concrete was mixed in the mixer with all ingredients with addition of remaining quantity of water as per water binder ratio obtained by mix design. The mix was thoroughly mixed by rotating the mixer drum for more than two minutes. The specimens were finished smooth after giving sufficient compaction. The specimens were finished smooth after giving sufficient compaction. Specimens were prepared with water to cementations materials ratio of 0.45 with 100mm slump. Different batches were adopted for different ages of curing. The cube specimens were cast and tested for studying the variation in strength properties due to the replacement of sand with CRP after curing for required period as per IS: 516-195924.

Carbon Dioxide Curing

To enable accelerated carbonation of concrete (i.e., Carbon dioxide curing) specimens, a CO2 chamber was constructed. Specimens stacked on racks made of perforated steel plates with sufficient gap for air circulation. A continuous CO2 gas was maintained in the chamber by burning 10 sambrani sticks in 20 minutes intervals continuously for a period of 6 hours. After passing the carbon dioxide the cubes are turned to light white colour.

Table 1 · Details of Mix Proportions
Materials Mixture Designation
NC RHC RHRP-10 RHRP-20 RHRP-40 RHRP-60 RHRP-80 RHRP-100
Cement (kg/m³) 400 360 360 360 360 360 360 360
RHA (kg/m³) 0 40 40 40 40 40 40 40
Sand (kg/m³) 781.78 774.41 696.67 619.05 463.94 309.29 154.64 0
CRP (kg/m³) 0 0 77.41 154.76 309.29 463.94 618.59 771.48
CA-20 mm max 1006.29 996.82 996.82 996.82 996.82 996.82 996.82 996.82
Water kg/m³ 198.10 194.82 195.15 195.48 196.14 196.8 197.47 198.09
NC = Normal Concrete
RHC = Rice Husk Ash Concrete
RHRP-10 = Rice Husk Ash and 10% crushed Rock Powder concrete
Table 2 · Compressive Strengths of Water Curing (WC) Concrete
Concrete Average Compressive strength in N/mm² Avg. SD
1 day WC 3 day WC 7 day WC 28 day WC
NC 9.62 19.85 32.81 46.51 3.1
RHC 8.14 13.33 22.22 41.16 3.0
RHRP-10 8.52 22.44 28.51 41.77 3.0
RHRP-20 7.29 19.11 21.25 32.51 3.2
RHRP-40 6.51 13.70 20.37 29.48 3.1
RHRP-60 5.62 14.22 23.48 29.62 3.2
RHRP-80 5.48 11.48 16.22 27.18 3.1
RHRP-100 5.33 10.88 15.55 24.88 3.0
FHRH-10 8.29 26 35.03 43.77 3.1
FHRH-20 7.11 21.77 27.92 30 3.0
FHRH-30 6.66 16.44 18.66 27.18 3.1
FHRH-40 3.85 13.03 20.74 34.44 3.0
FHRH-50 2.81 10.51 13.55 26.28 3.0
Table 3 · Compressive Strengths of WC in 28 Days and CC and AC/WC
Concrete Average Compressive strength in N/mm² Compressive strength
of concrete after 28
days WC in N/mm²
Avg. SD
6 hr CC
& 12 hr AC
6 hr CC
& 54 hr AC
6 hr CC, 12hr AC
& 42 hr WC
6 hr CC
& 150 hr AC
6 hr CC, 12hr AC
& 138 hr WC
NC 21.18 33.48 33.77 36.37 38.14 46.51 3.1
RHC 10.22 17.11 14.29 19.70 22 41.16 3.0
RHRP-10 21.18 21.77 18.81 25.55 23.62 41.77 3.0
RHRP-20 11.70 11.92 14.74 21.40 25.40 32.51 3.2
RHRP-40 14.37 20.29 22.22 20.18 20.70 29.41 3.1
RHRP-60 19.11 19.40 19.18 27.25 26.37 29.62 3.2
RHRP-80 15.29 24 22.66 28.81 25.11 27.18 3.1
RHRP-100 17.62 21.70 21.70 25.70 26.81 24.88 3.0
FHRH-10 20.74 28 26.74 37.11 25.55 43.77 3.0
FHRH-20 23.70 25.33 26.74 28 18.74 30 3.0
FHRH-30 15.62 25.85 21.40 23.11 15.63 27.18 3.1
FHRH-40 13.85 18 18.59 15.62 23.55 34.44 3.0
FHRH-50 11.55 17.18 16 9.85 9.93 26.28 3.1
Figure 3 · Comparison of compressive strengths of concrete with
different CRP levels2 curing
Figure 3
Figure 4 · Comparison of compressive strengths of WC concrete
v/s 6 hr CC and AC/WC2 curing
Figure 4
Figure 5 · Comparison of compressive strength of concrete with
different FHRH levels2 curing
Figure 5
Figure 6 · Comparison of compressive strength of WC concrete
v/s 6hr CC and AC/WC2 curing
Figure 6

Results and Discussions

The Compressive strengths of WC Concrete in 28 days and CC and AC/WC are shown in Table 2 and Table 3. The compressive strength of RHRP concrete of M30 grade containing constant 10% cement replaced by Rice husk-ash and natural sand (fine aggregate) replaced by CRP up to 20% is found to be satisfactory with little constraint with age of curing.

RHC gain the highest strength (i.e., 53.44 % of the NC cured in water for 28 days) in 6 hr CC, 12 hr AC and 138 hr WC.
It is advantageous to have Rice husk-ash concrete with 10% level of CRP replacement (i.e. RHRP-10) which exhibits almost equal values of strength parameters to RHC concrete of same grade even at age of 28days and even this level of RHRP concrete is better than RHC concrete.
The other mixes higher than 20% CRP showed lesser compressive strength than the mixes with river sand. This can be due to the voids present in the concrete mixes with higher amount of CRP.

From Table 1 it was noticed that the NC, FHRH-10 and FHRH-40 concrete specimens have achieved required concrete strength at 28 days water curing.
From Table 2 it was noticed that all concrete specimens have achieved more than 50% designed strength at 6 hrs CC and 12 air curing. Compressive strengths of different CRP levels for different water curing periods are shown in Figure 3 and Figure 4 respectively. It was noticed that all concrete specimens have achieved more than 50% designed strength at 6 hrs CC and 12hrs air curing.

From Figure 3 and Figure 4, presents the comparison of compressive strength of concrete with water curing and CO2 and air curing.
From Figure 5, it was observed that the FHRH-10 and FHRH-40 concrete specimens cured in water for 28 days exhibits higher strengths than other FHRH levels and slightly lower than the NC specimens.
From Figure 6, we see that more than 60% strength of M30 grade was achieved in 6hr CO2 curing and 12 hrs air curing for the specimens of NC and FHRH-10 and FHRH-40.

It was noticed that, there was a saving of up to 22% when CRP replaced sand. Further there was a saving up to 40% in the curing cost. Addition of rice husk ash also has helped in reducing the cost up to 4.5%.
It is recommended to use fly ash and rice husk ash as partial cement replacement materials in concrete up to 40% fly-ash and 10% rice husk ash respectively without loosing its original strength and other durability parameters of concrete.

The chemical reaction involves fixing of Ca(OH)2 in liquid phase from the hydrating cement with the silica in the pozzolana. For lower percentage replacement level such as 10%RHA the silica from the pozzolana is in required amount. This aids the hydration process producing blocks with high compressive strength. For higher percentage replacement level, the amount of rice husk ash in the mix is higher than required to combine with the liberated calcium hydroxide in the course of the hydration. The excess silica substitute part of the cementitious materials and consequently causing a reduction in strength.

Conclusions

This paper has examined how CRP and FH and RHA and CO2 curing affects the compressive strength and performance of concrete. The following conclusions can be drawn based on the experimentation in the laboratory:

Acknowledgements

The authors wish to place on record their sincere thanks to Dr. Shivakumariah, principal, SIT, Tumkur and Dr. M.N. Channabasappa, Director, SIT, for providing facilities to prepare this paper. Many thanks are extended to Dr. S V Dinesh, Head, Department of Civil Engineering, SIT, for his encouragement during the development of this paper.

References

  1. Papadakis V.G. & Tsimas S., Supplementary Cementing Materials for Sustainable Building Sector Growth, 2010, European Commission DGXII, Marie Curie Fellowship, Final Scientific Report, Project No HPMFCT- 1999-00370, National Technical University of Athens, Greece
  2. Raman S. N, Zain M. F. M., Mahmud H. B. & Tan K. S., Suitability of Quarry Dust as Partial Replacement Material for Sand in Concrete, 2008, eprints.um.edu.my/524/1/PTS3-3-8.pdf
  3. Ilangovana R., N. Mahendrana & Nagamanib K, Strength and Durability Properties of Concrete Containing Quarry Rock Dust as Fine Aggregate, 2008, ARPN Journal of Engineering and Applied Sciences ©2006-2008, VOL. 3, NO. 5, October, ISSN 1819-6608 Asian Research Publishing Network (ARPN).
  4. Chaturanga Lakshani Kapugamage, Aruna Lal Amarasiri, Patabandige Sumudu Prasanna Bandusena, Haniffa Mohamed Riyaz & Wiranjith Priyan Solomon Dias, Optimizing Concrete Mixes by Concurrent Use of Fly Ash and Quarry Dust. PP 1335-1342
  5. Alireza Naji Givi , Suraya Abdul Rashid , Farah Nora A. Aziz &, Mohamad Amran Mohd Salleh, Contribution of Rice Husk Ash to the Properties of Mortar and Concrete: A Review, 2010, Journal of American Science, (3).
  6. Habeeb G.A. & Fayyadh M.M., Rice Husk Ash Concrete: the Effect of RHA Average Particle Size on Mechanical Properties and Drying Shrinkage, 2009, Australian Journal of Basic and Applied Sciences, 3(3): 1616-1622
  7. Muhammad Harunur Rashid, M.D.Keramat Ali Molla & Tariffs Uddin Ahmed,”Mortar incorporating rice husk ash: strength and porosity”, 2010, European Journal of Scientific Research, ISSN 1450-216X Vol.40 No.3, , Euro Journals Publishing, Inc., pp.471-477
  8. Dao Van Dong, Pham Duy Huu &Nguyen Ngoc Lan, Effect of Rice Husk Ash on Properties of High Strength Concrete, 2008, The 3rd ACF International Conference - ACF/VCA.
  9. Mauro M.Tashima, Carlos A.R.Silva, Jorge L, Kasaki A & Michele Barbosa, Influence of rice husk ash in mechanical characteristics of concrete , 2008, IV International ACI/CANMET conference on quality of concrete structures and recent advances in concrete materials and testing, Paper XII.08-p,780-790
  10. Shao Y, S. Monkman & A. J. Boyd, Recycling carbon dioxide into concrete: a feasibility study, 2010, Concrete Sustainability Conference 1, at National Ready Mixed Concrete Association
  11. Felixkala T, Properties of HPC with Granite powder as Fine Aggregate, 2010, ICI Journal, April-June.
  12. Papadakis V.G. & Tsimas S., Supplementary Cementing Materials for Sustainable Building Sector Growth, 2010, European Commission DGXII, Marie Curie Fellowship, Final Scientific Report, Project No HPMFCT- 1999-00370, National Technical University of Athens, Greece
  13. Raman S. N, Zain M. F. M., Mahmud H. B. & Tan K. S., Influence of Quarry Dust and Fly Ash on the Concrete Compressive Strength Development, 2008, University Kebangsaan, Malaysia
  14. Satakhun Detphan & Prinya Chindaprasirt, Initial study on synthetics open-field burning rice husk ash : making geopolymer mortar for sustainable development in the rural area, 2008, Technology and Innovation for Sustainable Development Conference (TISD2008), 28-29 January
  15. Gambhir M.L., Concrete Technology – Second Edition, 1995, Tata McGraw-Hill Publishing Company Limited, New Delhi.
  16. Naidu R.S., Zain M.F.M. and Ang S.E., Compressive strength and pull-out force of concrete incorporating quarry dust and mineral admixtures, 2003, RILEM Proceedings 32: Proceedings of the International Conference on Advances in Concrete and Structure, Xuzhou, China.
  17. Celik T.and Marar K., Effects of crushed stone dust on some properties of concrete, 1996, Cement and Concrete Research 26 (7), pp. 1121-1130.
  18. Chun Y.M, T.R. Naik, & Kraus R.N, Carbon dioxide sequestration in concrete in different curing environments", UWM Center for By-Products Utilization, University of Wisconsin-Milwaukee, Milwaukee, WI, USA.
  19. Kauer J.A. & R.L.Freeman, Effect of carbon dioxide on fresh concrete, 1955, Journal of ACI, V.27, NO.4,Dec,proceedings V.52
  20. Owens K.J, P.A.M. Basheer & B. Sen Gupta, Utilization of Carbon Dioxide from Flue Gases to Improve Physical and Microstructural Properties of Cement and Concrete Systems, 2004, Centre for Built Environment Research, Queen”s University Belfast, Northern Ireland, UK.
  21. IS: 383–1970, Specifications for Coarse and Fine Aggregates From Natural Sources for Concrete, Bureau of Indian Standards.
  22. Edwin R. Dunstan Jr., How does Pozzolanic Reaction make concrete green?, 2011, World of a coal Ash (WOCA) conference, May 9-12, , Denver, Co, USA.
  23. IS: 10262-2009, Recommended guidelines for concrete mix design, Bureau of Indian Standards.
  24. IS: 516-1959, Methods of tests for strength of concrete, Bureau of Indian Standards.

***

Copyright © 2012, ECO Services International