**4.1 Road materials**

*Sandy Materials in Civil Engineering - Usage and Management*

**3.2 Chemical properties**

sand has a loss on ignition of 5.15%.

**3.3 Mechanical properties**

variation from sources to sources. Naik et al. [9] stated that the water absorption of used foundry sand is in the range of 0.38–4.15%. The fineness modulus of sand depends on the grading of the material. The surface moisture content of the sand can reduce the water requirement of the concrete and mortar mix. Most of the researchers did not report the fineness modulus and moisture content of the used foundry sand. However, Seshadri and Salim [12] and Kewal et al. [13] reported that waste foundry sand has a fineness modulus of 2.28 and 2.45, respectively. As per the physical properties stated by Guney et al. [14], the used foundry sand has a moisture content of 3.25%. A comparative graph of the gradation of natural sand and used foundry sand, as reported by Prabhu et al. [15], is shown in **Figure 2**.

The chemical properties of used foundry sand depend on the type of binders used in the foundry sand mixture. Johnson [11] reported that the pH of used foundry sand varies from 4 to 8. The used foundry sand consists of different metal oxides. These include SiO2, Al2O3, Fe2O3, CaO, MgO, SO3, Na2O, K2O, TiO2, Mn2O3, and SrO. Etxeberria et al. [16] stated that as far as the chemical constituents of used foundry sand were concerned, silicon dioxide constitutes the maximum contribution with 95.10% and the minimum by sulfur trioxide having a contribution of 0.03% of the total mass of used foundry sand. As per the chemical analysis of used foundry sand reported by American Foundrymen's Society [10], the spent foundry

The spent foundry sand has excellent mechanical properties at par with the conventional sand. American Foundrymen's Society [10] stated that the spent foundry sand has an angle of internal friction varying from 33° to 40°, and the California Bearing Ratio (CBR) values range from 4 to 20%. As per the reports of the Ministry of Natural Resources [17], the Micro-Deval Abrasion Loss of used foundry sand is

less than 2%, and Magnesium sulfate soundness loss varies from 5 to 15%.

**6**

**Figure 2.**

*Gradation of natural sand and foundry sand.*

The used foundry sand can be utilized as materials for road construction. Yazoghli-Marzouk et al. [18] studied the recycling of foundry sand in road construction. They found that treated used foundry sand with a 5.50% hydraulic binder did not show environmental impacts by leaching and has desirable mechanical properties and recommended the application of used foundry sand in the sub-base layer in road construction. The source of foundry sand was a stock of about 150,000 tons of foundry sand stock in Burgundy in France. Iqbal et al. [19] conducted studies on the operation of used foundry sand as a material for embankment, and structural fill further emphasized that sand replaced with 6% used foundry sand is best suitable for structural fill, embankment, and road sub-base material. Generally, it is believed that the compacted waste foundry sand can cause leaching of toxic constituents to the groundwater. But many pieces of research in this regard showed that waste foundry sand did not contaminate the surface water or groundwater. Arulrajah et al. [20] conducted the chemical composition analysis and leachate analysis of used foundry sand. They put forth the implementation of waste foundry sand in road embankment fill and pipe bedding applications. The waste foundry sand used in this research was provided by a recycling plant in Melbourne, Australia. The used foundry sand has superior qualities as that of conventional subbase material for road construction, and the usage of waste foundry sand can reduce the thickness of the sub-base layer, and thereby, construction cost can be reduced. Guney et al. [21] studied the properties of highway sub-bases with used foundry sand mixtures. They highlighted that the incorporation of used foundry sand can reduce the thickness of the sub-base layer in the sub-base construction of roads.

In the construction of flexible pavements too, the waste foundry sand can be employed to a noticeable extent. The aptness of the waste foundry sand in asphalt mixtures depends on several properties of waste foundry sand, including gradation, particle shape, cleanliness, and surface texture. In a case study on the different methods other than the landfill for the disposal of spent foundry sand generated from the small to medium enterprises in the United Kingdom, Nabhani et al. [22] stated that both green sand and chemically bonded sand could be beneficially replaced with virgin sand in the manufacture of asphalt with an impending extension of its useful working life to about 60 years. Apart from the working life extension, cost savings can also achieve by the replacement of virgin sand by used foundry sand. The used foundry sand incorporated asphalt mixtures are environmentally safe material having no adverse effects on the surroundings. Bakis et al. [23] conducted experiments on the properties of asphalt mixtures made with used foundry sand by replacing the aggregate in different fractions. The environmental impact on the use of used foundry sand also examined. As per the research findings of the investigation on the properties of the used foundry sand incorporated asphalt mixtures, it is described that the use of waste foundry sand in asphalt mixtures did not considerably affect the surrounding environment and further suggested that 10% aggregates can be replaced with the waste foundry sand in the production of asphalt mixtures. Javed et al. [24] investigated the possibilities of the usage of green sand from gray iron castings in asphalt concretes by replacing the total aggregates

by 15, 20, and 30% by weight. The bulk-specific gravity, theoretical-specific gravity, Marshall stability, and Marshall flow tests were conducted on the asphalt concrete samples incorporating used foundry sand and control asphalt concrete sample. From the research analysis, it is confirmed that the aggregates in asphalt concrete can be replaced with green sand obtained from gray iron castings up to a replacement level of 15%.

For road foundations also, used foundry sand can be employed in an efficient manner. Pasetto and Baldo [25] investigated the properties of road foundation mixtures made using cement, waste foundry sand, and steel slag in different proportions. The samples were tested after different curing periods for Proctor, compressive strength, indirect tensile strength, and elastic modulus by static and dynamic tests. From the analysis of hydraulically bound mixtures made with waste foundry sand and steel slag, it is noted that the used foundry sand with cement and steel slag showed satisfactory results as per the norms of Italian Road Technical Standards, and the mixture containing 80% of steel slag and 20% of waste foundry sand gives the optimum characteristics. The used foundry sand can be employed in structural fill, embankment, road sub-base, and asphalt concrete mixtures either independently or with other materials like cement and steel slag.

#### **4.2 Cement concrete**

The waste foundry sand gradation is mostly outside the lower limits for fine aggregates used in concrete. It is worthwhile to note that the grading of used foundry sand is too fine to satisfy the specifications of fine aggregate. Hence, the waste foundry sand can replace the fine aggregates in cement concrete to some extent only. **Figure 3** shows the grading curve for used foundry sand as per the sieve analysis by Khatib et al. [26] and the gradation limits for fine aggregates as per ASTM-C-33 [27].

#### *4.2.1 General concretes*

In general-purpose concretes, used foundry sand finds extensive applications. The used foundry sand is an effective substitute to fine aggregate in general-purpose concretes having strength parameters ranging from low strength to ultra-high strength. Many researchers found that used foundry sand is effective in reducing the usage of fine aggregate in common concretes to a greater extent. Manoharan et al. [28] investigated the characteristics of concrete with chemically bonded used foundry sand in concrete with characteristic compressive strength of 20 MPa having natural river sand replaced with 0, 5, 10, 15, 20, and 25% of used foundry sand and reported that the strength parameters of used foundry sand incorporated concrete containing 5–20% used foundry sand are similar to the control mix with 100% natural river sand of 4.75 mm maximum size as fine aggregate and 20 mm size crushed granite as coarse aggregate. The used foundry sand can reduce the cost of construction, too, to some extent. Bhimani et al. [29] stated that the concrete made with river sand and 20 mm downgraded crushed basalt rock aggregates with a 28th-day compressive strength of 20 MPa and a cost reduction of 3.39% could be achieved by replacing 50% river sand with waste foundry sand in the concrete mix.

In medium strength concrete with a characteristic compressive strength equal to or greater than 30 MPa, used foundry sand is an efficient replacement material to fine aggregates, without compromising on the qualities of the concrete produced. Sohail et al. [30] investigated the properties of concrete of a characteristic compressive strength of 30 MPa made with river sand as fine aggregate and

**9**

the control concrete.

*A Review on the Usage of Recycled Sand in the Construction Industry*

20 mm nominal size crushed granite rock aggregates along with green sand from gray iron foundry as a substitute to river sand at 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100% and reported that up to 70% river sand could be replaced with used foundry sand for the concrete with sufficient strength parameters. The abrasion resistance and the strength properties of concrete having 40 MPa compressive strength at 28 days made with 4.75 mm nominal size natural sand and 12.50 mm nominal size coarse aggregate with used foundry sand as a partial substitute to river sand at 0, 5, 10, 15, and 20% were investigated by Singh and Siddique [31] and reported in similar lines that up to 20% natural sand could be replaced with used foundry sand for the production of the concrete having desirable properties and further notified that the incorporation of used foundry sand increased the

Natural fine aggregates can be replaced with waste foundry sand for the production of high strength concrete also. Guney et al. [14] investigated the application of waste green foundry sand in high strength concrete of compressive strength of 65 MPa at 28 days made with fine sand replaced with waste foundry sand at 0, 5, 10, and 15% by weight of fine sand. They reported that the high strength concrete made with a replacement of 10% of fine aggregates with waste foundry sand exhibited strength parameters at par with the control concrete made with fine sand as fine aggregate. In this research, it is further noted that the freezing and thawing reduced the physical and mechanical properties of concrete by the addition of waste foundry sand to the concrete; however, the strength parameters were found to be acceptable as per the norms fixed by the American Concrete Institute. Chandrasekar et al. [32] succeeded in developing high strength concrete with green sand by partially replacing river sand of 4.75 mm maximum size by 0, 10, 20, 30, and 40% with waste foundry sand and 12.5 mm nominal size coarse aggregate. Slump, compressive strength, split tensile strength, flexural strength, and modulus of elasticity were determined on the samples produced. The effects of the concrete on elevated temperature were also studied. Based on the analysis of the test results, it is confirmed that it is very much possible to replace the fine aggregates with used foundry sand in the range of 10–20% for the production of high strength concrete having a 28th-day compressive strength of 60 MPa for better strength characteristics than

Experimentally, it is proved that ultra-high-strength concrete can be made with used foundry sand as a partial substitute to fine aggregate. Torres et al. [33]

*DOI: http://dx.doi.org/10.5772/intechopen.92790*

abrasion resistance of the concrete.

**Figure 3.**

*Used foundry sand grading curve.*

*A Review on the Usage of Recycled Sand in the Construction Industry DOI: http://dx.doi.org/10.5772/intechopen.92790*

**Figure 3.** *Used foundry sand grading curve.*

*Sandy Materials in Civil Engineering - Usage and Management*

replacement level of 15%.

**4.2 Cement concrete**

per ASTM-C-33 [27].

*4.2.1 General concretes*

by 15, 20, and 30% by weight. The bulk-specific gravity, theoretical-specific gravity, Marshall stability, and Marshall flow tests were conducted on the asphalt concrete samples incorporating used foundry sand and control asphalt concrete sample. From the research analysis, it is confirmed that the aggregates in asphalt concrete can be replaced with green sand obtained from gray iron castings up to a

independently or with other materials like cement and steel slag.

For road foundations also, used foundry sand can be employed in an efficient manner. Pasetto and Baldo [25] investigated the properties of road foundation mixtures made using cement, waste foundry sand, and steel slag in different proportions. The samples were tested after different curing periods for Proctor, compressive strength, indirect tensile strength, and elastic modulus by static and dynamic tests. From the analysis of hydraulically bound mixtures made with waste foundry sand and steel slag, it is noted that the used foundry sand with cement and steel slag showed satisfactory results as per the norms of Italian Road Technical Standards, and the mixture containing 80% of steel slag and 20% of waste foundry sand gives the optimum characteristics. The used foundry sand can be employed in structural fill, embankment, road sub-base, and asphalt concrete mixtures either

The waste foundry sand gradation is mostly outside the lower limits for fine aggregates used in concrete. It is worthwhile to note that the grading of used foundry sand is too fine to satisfy the specifications of fine aggregate. Hence, the waste foundry sand can replace the fine aggregates in cement concrete to some extent only. **Figure 3** shows the grading curve for used foundry sand as per the sieve analysis by Khatib et al. [26] and the gradation limits for fine aggregates as

In general-purpose concretes, used foundry sand finds extensive applications. The used foundry sand is an effective substitute to fine aggregate in general-purpose concretes having strength parameters ranging from low strength to ultra-high strength. Many researchers found that used foundry sand is effective in reducing the usage of fine aggregate in common concretes to a greater extent. Manoharan et al. [28] investigated the characteristics of concrete with chemically bonded used foundry sand in concrete with characteristic compressive strength of 20 MPa having natural river sand replaced with 0, 5, 10, 15, 20, and 25% of used foundry sand and reported that the strength parameters of used foundry sand incorporated concrete containing 5–20% used foundry sand are similar to the control mix with 100% natural river sand of 4.75 mm maximum size as fine aggregate and 20 mm size crushed granite as coarse aggregate. The used foundry sand can reduce the cost of construction, too, to some extent. Bhimani et al. [29] stated that the concrete made with river sand and 20 mm downgraded crushed basalt rock aggregates with a 28th-day compressive strength of 20 MPa and a cost reduction of 3.39% could be achieved by replacing 50% river sand with waste foundry sand in the concrete mix. In medium strength concrete with a characteristic compressive strength equal to or greater than 30 MPa, used foundry sand is an efficient replacement material to fine aggregates, without compromising on the qualities of the concrete produced. Sohail et al. [30] investigated the properties of concrete of a characteristic compressive strength of 30 MPa made with river sand as fine aggregate and

**8**

20 mm nominal size crushed granite rock aggregates along with green sand from gray iron foundry as a substitute to river sand at 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100% and reported that up to 70% river sand could be replaced with used foundry sand for the concrete with sufficient strength parameters. The abrasion resistance and the strength properties of concrete having 40 MPa compressive strength at 28 days made with 4.75 mm nominal size natural sand and 12.50 mm nominal size coarse aggregate with used foundry sand as a partial substitute to river sand at 0, 5, 10, 15, and 20% were investigated by Singh and Siddique [31] and reported in similar lines that up to 20% natural sand could be replaced with used foundry sand for the production of the concrete having desirable properties and further notified that the incorporation of used foundry sand increased the abrasion resistance of the concrete.

Natural fine aggregates can be replaced with waste foundry sand for the production of high strength concrete also. Guney et al. [14] investigated the application of waste green foundry sand in high strength concrete of compressive strength of 65 MPa at 28 days made with fine sand replaced with waste foundry sand at 0, 5, 10, and 15% by weight of fine sand. They reported that the high strength concrete made with a replacement of 10% of fine aggregates with waste foundry sand exhibited strength parameters at par with the control concrete made with fine sand as fine aggregate. In this research, it is further noted that the freezing and thawing reduced the physical and mechanical properties of concrete by the addition of waste foundry sand to the concrete; however, the strength parameters were found to be acceptable as per the norms fixed by the American Concrete Institute. Chandrasekar et al. [32] succeeded in developing high strength concrete with green sand by partially replacing river sand of 4.75 mm maximum size by 0, 10, 20, 30, and 40% with waste foundry sand and 12.5 mm nominal size coarse aggregate. Slump, compressive strength, split tensile strength, flexural strength, and modulus of elasticity were determined on the samples produced. The effects of the concrete on elevated temperature were also studied. Based on the analysis of the test results, it is confirmed that it is very much possible to replace the fine aggregates with used foundry sand in the range of 10–20% for the production of high strength concrete having a 28th-day compressive strength of 60 MPa for better strength characteristics than the control concrete.

Experimentally, it is proved that ultra-high-strength concrete can be made with used foundry sand as a partial substitute to fine aggregate. Torres et al. [33] investigated the properties of ultra-high-strength concretes of 120 MPa compressive strength at 28 days made with 3.35 mm well-graded manufactured sand from limestone and river sand as fine aggregates and 6.35 mm size limestone and pea gravel as coarse aggregates along with spent foundry sand. In this research, fine aggregates were replaced by foundry sand at 0, 10, 20, and 30%. As an outcome of the study, it is noted that for optimum performance of the ultra-high-strength concrete, the river sand could be replaced with 10% spent foundry sand in the mix, which uses no coarse aggregates at all.

Nowadays, the requirements of fresh concrete in all the infrastructure projects are met with the ready-mixed concrete (RMC). By using the ready-mixed concrete of required grade, the quality of the concrete can be maintained better than the site mixed concrete. Many kinds of research were conducted on the feasibility of employing used foundry sand in the production of ready-mixed concrete also. Basar and Aksoy [34] conducted experiments on the effect of waste foundry sand as a partial substitute in 0, 10, 20, 30, and 40% of regular sand on the mechanical, leaching, and microstructural characteristics of ready-mixed concrete. The results of the various tests revealed that the typical regular sand in the replacement level of 20% with used foundry sand gives satisfactory mechanical and physical properties in the ready-mixed concrete incorporating used foundry sand.

### *4.2.2 Special concretes*

The used foundry sand can be employed in special concretes like high-performance concrete, self-compacting concrete, high-performance self-compacting concrete, and lightweight concrete. Salim et al. [6] stated that high-performance concrete is high-strength concrete, having desired properties and uniform characteristics. Seshadri and Salim [12] investigated the features of high-performance concrete of design compressive strength of 60 MPa at 28 days with manufactured sand and 20 mm nominal size crushed stone aggregates as fine aggregates and coarse aggregates, respectively, in which fine aggregates were partially replaced by chemically bonded used foundry sand from 0 to 40% in 5% increments and found that up to 30% manufactured sand can be replaced with used foundry sand in the production of high-performance concrete with satisfactory strength characteristics. Ranjitham et al. [35] investigated the properties of 75 MPa characteristic compressive strength high-performance concrete made with 12.5 mm maximum size coarse aggregate and 4.75 mm maximum size river sand as fine aggregate with partial replacement of river sand by green foundry sand and reported that 10% addition of used foundry sand gives excellent strength properties than that of the control concrete without used foundry sand for high-performance concrete of 75 MPa characteristic compressive strength.

For the manufacture of self-compacting concrete also, the used foundry sand can be employed for the reduction in the consumption of the natural fine aggregates. The self-compacting concrete is a type of concrete that does not need external mechanical vibration for the compaction. The self-compacting concrete having strength characteristics in line with the concrete with conventional fine aggregates can be made with partial replacement of fine aggregates with used foundry sand. Siddique and Sandhu [36] reported that self-compacting concrete having a design characteristic compressive strength of 30 MPa made with 15% normal sand replaced by waste foundry sand and 10–12 mm maximum size coarse aggregate exhibited sufficient strength characteristics. Nirmala and Raviraj [37] conducted experiments on the optimization of the self-compacting concrete with used foundry sand as a partial substitute for manufactured sand (M-sand) using the Taguchi approach. The slump flow, V-funnel flow, U-box, L-box, and compressive strength

**11**

*A Review on the Usage of Recycled Sand in the Construction Industry*

tests were conducted. On the basis of the results obtained, it is noted that for obtaining optimum strength properties for the self-compacting concrete, 20% of manufactured sand (M-sand) should be replaced with spent foundry sand.

In modern construction practice, high-performance self-compacting concrete has great applications where the complicated molds are in use, and the reinforcement steels are very much congested. In this particular situation also, foundry sand waste can be employed with other materials in the production of self-compacting concrete. The high-performance self-compacting concrete has superior early as well as long-term durability and mechanical strength parameters. Makul [38] investigated the properties of high-performance self-consolidating concrete made with waste rice husk ash and foundry sand waste with water to binder ratios of 0.35 and 0.45 where the ordinary portland cement was replaced by rice husk ash in 10 and 20% by weight and the fine aggregate was replaced with foundry waste sand in 30 and 50% by weight. The foundry sand waste used was obtained from automobile part casting foundry. The slump flow, V-funnel flow, splitting tensile strength, and compressive strength tests were performed. Based on the test results, it is observed that the high-performance self-compacting concrete made with 30% replacement of fine aggregates with foundry sand waste and 10% cement replaced with rice husk ash has higher compressive and tensile strength than the conventional self-

Lightweight concrete is concrete, having less density than the regular concrete. In certain applications, regular concrete cannot be entertained due to its higher dead weight. In such situations, lightweight concrete can be effectively utilized. For the manufacture of lightweight concrete also, used foundry sand can be employed efficiently. Hossain and Anwar [39] reported that by the use of waste foundry sand and volcanic ash, lightweight concrete (LWC) can be made economically for the promotion of sustainable construction by reducing the disposal problems of waste

Geopolymer concrete is an innovation in the field of concrete in which cement is not a constituent. In geopolymer concrete also, the waste foundry sand can be used in place of fine aggregates in various replacement levels. Dogan-Saglamtimur [3] investigated the waste foundry sand usage in geopolymer concrete made with sodium hydroxide or sodium silicate for building material production and maximum compressive strength of 12.3 MPa obtained for waste foundry sand incorporated geopolymer concrete containing 30% sodium silicate when the samples were cured at 200°C. The waste foundry sand used in this research is of green sand, which contained bentonite. Based on the results obtained, it is confirmed that the geopolymer material produced with waste foundry sand is suitable for use as a building wall material. For the manufacture of geopolymer concrete cured in ambient temperature also, used foundry sand can be employed in place of fine aggregates. Bhardwaj and Kumar [40] studied the effect of green sand from the ferrous foundry on ambient cured geopolymer concrete. They stated that up to 60% replacement level of fine aggregates to waste foundry sand, the strength parameters are improved better than that of the conventional geopolymer concrete. Scanning electron microscope (SEM) image of concrete of compressive strength of 46 MPa containing 100% chemically bonded foundry sand (FS), as reported by

In another study on geopolymer concrete made with manufactured sand as fine aggregate with partial replacement of fine aggregate at 0, 5, 10, 15, 20, and 25% by weight of fine aggregate with foundry sand, Jerusha and Mini [42] studied the

*DOI: http://dx.doi.org/10.5772/intechopen.92790*

compacting concrete of the control mix.

Mavroulidou and Lawrence [41], is shown in **Figure 4**.

foundry sand and volcanic ash.

**4.3 Geopolymer concrete**

#### *A Review on the Usage of Recycled Sand in the Construction Industry DOI: http://dx.doi.org/10.5772/intechopen.92790*

*Sandy Materials in Civil Engineering - Usage and Management*

in the ready-mixed concrete incorporating used foundry sand.

which uses no coarse aggregates at all.

*4.2.2 Special concretes*

characteristic compressive strength.

investigated the properties of ultra-high-strength concretes of 120 MPa compressive strength at 28 days made with 3.35 mm well-graded manufactured sand from limestone and river sand as fine aggregates and 6.35 mm size limestone and pea gravel as coarse aggregates along with spent foundry sand. In this research, fine aggregates were replaced by foundry sand at 0, 10, 20, and 30%. As an outcome of the study, it is noted that for optimum performance of the ultra-high-strength concrete, the river sand could be replaced with 10% spent foundry sand in the mix,

Nowadays, the requirements of fresh concrete in all the infrastructure projects are met with the ready-mixed concrete (RMC). By using the ready-mixed concrete of required grade, the quality of the concrete can be maintained better than the site mixed concrete. Many kinds of research were conducted on the feasibility of employing used foundry sand in the production of ready-mixed concrete also. Basar and Aksoy [34] conducted experiments on the effect of waste foundry sand as a partial substitute in 0, 10, 20, 30, and 40% of regular sand on the mechanical, leaching, and microstructural characteristics of ready-mixed concrete. The results of the various tests revealed that the typical regular sand in the replacement level of 20% with used foundry sand gives satisfactory mechanical and physical properties

The used foundry sand can be employed in special concretes like high-performance concrete, self-compacting concrete, high-performance self-compacting concrete, and lightweight concrete. Salim et al. [6] stated that high-performance concrete is high-strength concrete, having desired properties and uniform characteristics. Seshadri and Salim [12] investigated the features of high-performance concrete of design compressive strength of 60 MPa at 28 days with manufactured sand and 20 mm nominal size crushed stone aggregates as fine aggregates and coarse aggregates, respectively, in which fine aggregates were partially replaced by chemically bonded used foundry sand from 0 to 40% in 5% increments and found that up to 30% manufactured sand can be replaced with used foundry sand in the production of high-performance concrete with satisfactory strength characteristics. Ranjitham et al. [35] investigated the properties of 75 MPa characteristic compressive strength high-performance concrete made with 12.5 mm maximum size coarse aggregate and 4.75 mm maximum size river sand as fine aggregate with partial replacement of river sand by green foundry sand and reported that 10% addition of used foundry sand gives excellent strength properties than that of the control concrete without used foundry sand for high-performance concrete of 75 MPa

For the manufacture of self-compacting concrete also, the used foundry sand can be employed for the reduction in the consumption of the natural fine aggregates. The self-compacting concrete is a type of concrete that does not need external mechanical vibration for the compaction. The self-compacting concrete having strength characteristics in line with the concrete with conventional fine aggregates can be made with partial replacement of fine aggregates with used foundry sand. Siddique and Sandhu [36] reported that self-compacting concrete having a design characteristic compressive strength of 30 MPa made with 15% normal sand replaced by waste foundry sand and 10–12 mm maximum size coarse aggregate exhibited sufficient strength characteristics. Nirmala and Raviraj [37] conducted experiments on the optimization of the self-compacting concrete with used foundry sand as a partial substitute for manufactured sand (M-sand) using the Taguchi approach. The slump flow, V-funnel flow, U-box, L-box, and compressive strength

**10**

tests were conducted. On the basis of the results obtained, it is noted that for obtaining optimum strength properties for the self-compacting concrete, 20% of manufactured sand (M-sand) should be replaced with spent foundry sand.

In modern construction practice, high-performance self-compacting concrete has great applications where the complicated molds are in use, and the reinforcement steels are very much congested. In this particular situation also, foundry sand waste can be employed with other materials in the production of self-compacting concrete. The high-performance self-compacting concrete has superior early as well as long-term durability and mechanical strength parameters. Makul [38] investigated the properties of high-performance self-consolidating concrete made with waste rice husk ash and foundry sand waste with water to binder ratios of 0.35 and 0.45 where the ordinary portland cement was replaced by rice husk ash in 10 and 20% by weight and the fine aggregate was replaced with foundry waste sand in 30 and 50% by weight. The foundry sand waste used was obtained from automobile part casting foundry. The slump flow, V-funnel flow, splitting tensile strength, and compressive strength tests were performed. Based on the test results, it is observed that the high-performance self-compacting concrete made with 30% replacement of fine aggregates with foundry sand waste and 10% cement replaced with rice husk ash has higher compressive and tensile strength than the conventional selfcompacting concrete of the control mix.

Lightweight concrete is concrete, having less density than the regular concrete. In certain applications, regular concrete cannot be entertained due to its higher dead weight. In such situations, lightweight concrete can be effectively utilized. For the manufacture of lightweight concrete also, used foundry sand can be employed efficiently. Hossain and Anwar [39] reported that by the use of waste foundry sand and volcanic ash, lightweight concrete (LWC) can be made economically for the promotion of sustainable construction by reducing the disposal problems of waste foundry sand and volcanic ash.

#### **4.3 Geopolymer concrete**

Geopolymer concrete is an innovation in the field of concrete in which cement is not a constituent. In geopolymer concrete also, the waste foundry sand can be used in place of fine aggregates in various replacement levels. Dogan-Saglamtimur [3] investigated the waste foundry sand usage in geopolymer concrete made with sodium hydroxide or sodium silicate for building material production and maximum compressive strength of 12.3 MPa obtained for waste foundry sand incorporated geopolymer concrete containing 30% sodium silicate when the samples were cured at 200°C. The waste foundry sand used in this research is of green sand, which contained bentonite. Based on the results obtained, it is confirmed that the geopolymer material produced with waste foundry sand is suitable for use as a building wall material. For the manufacture of geopolymer concrete cured in ambient temperature also, used foundry sand can be employed in place of fine aggregates. Bhardwaj and Kumar [40] studied the effect of green sand from the ferrous foundry on ambient cured geopolymer concrete. They stated that up to 60% replacement level of fine aggregates to waste foundry sand, the strength parameters are improved better than that of the conventional geopolymer concrete. Scanning electron microscope (SEM) image of concrete of compressive strength of 46 MPa containing 100% chemically bonded foundry sand (FS), as reported by Mavroulidou and Lawrence [41], is shown in **Figure 4**.

In another study on geopolymer concrete made with manufactured sand as fine aggregate with partial replacement of fine aggregate at 0, 5, 10, 15, 20, and 25% by weight of fine aggregate with foundry sand, Jerusha and Mini [42] studied the

**Figure 4.** *SEM image of concrete containing 100% FS.*

slump of the fresh geopolymer concrete and compressive strength of hardened geopolymer concrete samples at 3rd day, 7th day, and 28th day and found that the optimum replacement percentage of foundry sand to the fine aggregate is 15% for the geopolymer concrete made of foundry sand, and the maximum compressive strength obtained was 21.33 MPa.
