1. Introduction
In the last decades, sustainability has been the primitive objective of the existing non-sustainable and rapid industrialization for both developed and developing countries. Especially with developing countries that adopt vast construction and upgrading their infrastructure evolving as much material waste. These material wastes are usually provided from industrial by-products. Hence, it is difficult to further process them as sustainable materials while experiencing difficulty in their disposal of vast quantities that increase daily. Most industrial wastes are considered non-sustainable materials. Concrete manufacturing, the second material utilized all over the world [
1], possesses a higher environmental impact through its carbon footprint. Furthermore, traditional concrete ingredients utilize materials such as cement, and aggregate, in addition to their manufacturing possess also carbon footprint as well [
2]. Several wastes such as granite, glass, rubber, ceramic, and marble were suggested as recycled wastes in concrete manufacturing as a fine, coarse aggregate and as cement replacement in some cases [
1,
2,
3,
4,
5]. Ceramic waste powder (CWP) is usually generated while manufacturing as a result of defective ceramic products and the shaping of ceramic tiles. Several studies [
6,
7] explored the utilization of ceramic wastes as cement, fine, and coarse aggregate replacement. Their results addressed a remarkable percentage of CWP utilization, around 30%.
Most recent work addresses the CWP utilization as a replacement in normal concrete. Few addressed the CWP utilization in self-compacted concrete (SCC) as a partial substitute for cement since SCC has been developed as a great revolution in the construction industry that requires no external vibration for full compaction. Various benefits compared to normal concrete from labor cost reduction, to period, and design versatility [
8]. However, no significant study has been accomplished on the CWP as a partial substitute for cement while replacing fine aggregate with glass in SCC [
9] despite the huge other recycled wastes possessed through manufacturing and building demolition.
Several studies [
4,
9,
10,
11,
12,
13,
14,
15,
16,
17] investigated the utilization of CWP as a cement replacement in SCC to examine their impact at different percentages. Subasi et al. [
4] reported that 15 to 20% CWP as cement replacement provided a positive effect on the rheological properties of SCC. Aly et al. [
10] observed that limited cement replacement ranges between 20 to 30% CWP (by weight) reduced the cement paste/concrete porosity, which in turn enhanced the mechanical and durability characterization of SCC. As the rheological properties of the SCC are influenced by the setting time and hydration process, Li et al. [
11] observed that the CWP inclusion increases both the initial and final setting times of SCC. Moreover, Sivaprakash et al. [
12] evaluated the CWP as cement replacement under 14 days of curing while producing concrete with grade M25. Agarwal et al. [
6] concluded that increasing the CWP as cement replacement, reduced the concrete density decreases while workability kept constant. Mohit et al. [
13] have explored mortars not concrete while utilizing CWP as a partial cement replacement. The results revealed that the mortars incorporating 5% CWP as cement replacement provided the highest mechanical strength compared to others at 14, 28, 42, and 56 days of acid curing which is reflected in XRD by the lower intensity of Portlandite (Ca(OH)
2) peaks than the reference specimen. Their SEM images showed a reduction of pores and voids confronting the enhancement against an acidic environment. Alsaif [
14] concluded that a beneficial influence on most properties in rheological and mechanical properties specifically workability and compressive strength despite the degraded indication of the durability it was concluded that in most cases enhanced. Further, the microstructure of the produced concrete showed a denser matrix. Alternatively, El-Dieb et al. [
15] reported the pozzolanic activity of the CWP replacement partially of cement as 80% of its chemical composition contains mainly silica (SiO
2) and alumina (Al
2O
3), which mainly contains more than 80% of the CWP composition showing pozzolanic activity at late ages. Moreover, they addressed the CWP utilization in SCC and recorded their integration to international requirements while their inclusion enhanced rheological and durability performance at optimized strength in which 40% CWP could be utilized as partial cement replacement. On the other hand, Chen et al. [
16] investigated including the RCA as a replacement of aggregate while replacing the cement with CWP and demonstrated about 10% to 20% CWP inclusion provided a high strength and enhanced the strength of recycled coarse aggregate (RAC) at 56 days despite the reduction in early age strength of RAC at increased CWP content further than 20%. A range of 10 to 20% CWP enhanced the RAC capillary water absorption and chloride ion penetration resistance, specifically when 60% RCA and 10% CWP were utilized simultaneously, which attributed to the micro-filler effects and low pozzolanic reactivity of CWP. Similar findings were deduced by El-Dieb and Kanaan [
9] and Mohit and Sharifi [
17] who added that 10% to 20%CWP is more effective for cement substitutes, 10% for early ages, and 20% for later ages. Further, Kannan et al. [
18] recommended the inclusion of CWP in a range of 10 to 40% as a partial cement replacement as it would provide high-performance concrete and excellent durability. Nevertheless, the attitude towards the improvement was explored by microstructure which ensured no significant effect on cement hydration and confronted the creation of dense packing particles.
On the other hand, several researchers [
19,
20,
21,
22,
23,
24] recommended the utilization of glass as a replacement for concrete ingredients especially fine aggregate as it provides unique performance. In addition to the fine aggregate replacement, the privileges of glass from having thermal and ecological impacts on the environment was proven when used as lightweight brick as stated by Ketov et al. [
25]. In addition, the ecological advantages compared to raw materials where the mining process provides emissions while recycled waste requires some treatment process like crushing, etc. Shayan and Xu [
19] stated that the mixed color glass in concrete could be used as coarse aggregate (4.75 – 12 mm), fine aggregate (0.15 – 4.75 mm), or as an SCM when ground to form glass power (<10 mm) as partial cement replacement. Hamada et al. [
20] explored the utilization of waste glass aggregates (WGA) and their influence on concrete performance. Their observation summed up that several factors could influence the mechanical and durability of WGA concrete such as size, type, replacement ratio, mixing method, and curing condition. The main reasoning was the WGA refined pore structure and densified microstructure. Their results revealed that the best performance was when utilizing the WGA as a fine aggregate replacement; however, the optimum replacement levels varied from 20 to 30% for fine aggregates and 10 to 20% for coarse aggregates with an indication of lighter-weight concrete than natural aggregate. Moreover, Sharifi et al. [
21] incorporated recycled glass as fine aggregate in SCC concrete to assess the rheological, strength, and durability properties at 5 different portions.
Further investigation of combining recycled wastes as replacement of coarse and fine aggregate in addition to the cement replacement. For instance, Kou and Poon [
22] explored the rheological and mechanical properties of the SCC-incorporated recycled glass (RG) less than 5 mm in size along with crushed granite of a maximum size of 20 mm. They concluded that RG is economically, eco-friendly, and structurally while providing strength at acceptable limits by code and guidelines. Srikanth and Lalitha [
23] prepared SCC utilizing several percentiles of WGA as partial substituting fine aggregate. Their results observed that the optimum WGA replacement to satisfy the SCC rheological properties was 30% while for best performance in mechanical properties was 35% of cement replacement combined with 30% of fine aggregate replacement. Finally, Singh and Siddique [
24] incorporated metakolin along with RG into 24 different SCC mixtures. Slump flow, V-funnel, L-box, and U-box tests related to SCC's passing and flowing ability were enhanced as the CRG content increased in the mix; however, mechanical properties were decreased. Thus, substituting the cement with MK in CRG-incorporated SCC mixtures improved the strength properties at all the glass replacement levels.
Several research studies were carried out to observe the effect of various recycled and waste materials in manufacturing self-compacted concrete executed in many countries. Multiple replacements of recycled and waste materials with all-natural concrete ingredients existed. Hence, it is deduced from the previous studies the significant effect of CWP and RG on SCC performance with the recommendation of RG as a fine aggregate replacement. Thus, this study aimed to discover the impact of CWP on SCC production as a partial cement replacement while combining glass as a fine aggregate replacement. The CWP was replaced by 15, 20, and 25%, with a gradual replacement of the fine aggregate by 5% by weight reaching 15%.
5. Testing Method
The tests for the self-compacted concrete here took two phases: phase I at the rheological state and phase II hardened state after curing. Phase I consists of test sets for SCC: slump flow, slump T
500, J-ring, V-funnel, V-funnel T
5 min, and L-box. The tests were handled according to ASTM C1611 [
32], C1621 [
33], EN 12350-9 [
34], and EN 12350-10 [
35]. The upper and lower limits for each rheological test are addressed in
Table 3 as per ECP 203 [
28].
The rheological test can be explained and illustrated as follows:
The test is handled through ASTM C1611 [
32] which states that the sample of fresh concrete should be placed into the frustum on the rigid plate. The frustum is then removed so that the freshly mixed concrete would flow into a diameter range between 600 to 800 mm as assigned by ECP 203 [
28] and presented in
Table 3.
Figure 3 shows the determination of diameter by measuring the slump flow diameter perpendicular to each other and getting the average diameter through the below Eq. [
1]:
Where D1 and D2 are the diameters of the slump flow for SCC crossing each other perpendicularly.
- b)
Slump flow time at T50 cm
Similar to the previous test, fresh concrete is poured inside the frustum which is placed on the rigid plate with the engraved indication for a diameter ring of 500 mm, as shown in
Figure 4. Then, the frustum is removed while the stopwatch is counting the time elapsed for the slump flow to reach a diameter of 500 mm in seconds [
33]. The ECP 203 [
28] assigned a range of 2 to 5 seconds.
- c)
J-ring flow
The test examines the ability of concrete to pass (pass ability) through a reinforcement diameter of 16 mm and spacing of 59 mm, see
Figure 5. The selection of diameter and spacing of 16 mm was based on the average sizing of bars as per ASTM C1621 [
33]. The slump flow through the J-ring is calculated by measuring the two diameters crossing each other perpendicularly and getting the average between them as the following Eq [
2].
The ECP 203 [
28] defined the upper and lower limits for the diameter is the fresh concrete to pass the reinforcement with a margin of 0 to 20 mm increase in diameter (300+0 or 300+20), as illustrated in
Figure 5.
- d)
V-funnel
The test starts using the V-funnel as appeared in
Figure 6. The V-funnel is dimensioned 515 and 75 with a height of 450 mm and a rectangular end of 65 and 75 mm, see
Figure 6. This rectangular end has a sliding gate that opens when the V-funnel is filled where a cylinder is placed to be filled with fresh concrete. The time elapsed for falling the concrete into the cylinder is measured using a stopwatch. The ECP203 [
28] assigned a margin of 6 to 12 seconds for the concrete to fill in the cylinder and fall all from the V-funnel. This elapsed time is denoted by (t
o). The idea of the test is to evaluate the flowability of concrete continuously and that no blockage could occur while casting the concrete. In addition, the concrete amended the required viscosity and filling ability as self-compacting concrete [
34].
- e)
V-funnel after 5 minutes
Similar to the testing assigned above, the V-funnel can undergo another way of testing by leaving the freshly mixed concrete in the funnel for 5 minutes after cast and before opening the gates, see
Figure 6. Then, the free fall of the mixed concrete into the cylinder would provide the suitability of this nix for being SCC without blockage or missing the necessary viscosity after the start-up of the hydration process for 5 minutes. The test examines the period required for filling the formwork after initiating the hydration process towards the initial setting time which in this case would be heavily filling the voids and passing through reinforcement shaping the mold or formwork [
34]. The time elapsed is measured using the stopwatch and the limits amended by ECP 203 [
28] are calculated from (t
o) since it was measured in the previous step to (t
o+3), as shown in
Table 3. It should be recalled that the limit of t
o is between 6 to 12 seconds which means that the limit in V-funnel testing after 5 minutes is between 9 to 15 seconds [
28].
- f)
L-box test
The idea of the L box test is similar to the that of J-ring and it is main purpose is to evaluate the passing ability of SCC through passing by the concrete’s weight through tight openings including congested reinforcement at different spacing. The test is amending only to spaces on 41 mm with three reinforcement bars and the other with 59 mm between bars only, as shown in
Figure 7. A ratio is measured between the vertical section height (H
1) and the height of concrete at the horizontal section H
2 as clarified in
Figure 7. Eq. [
3] shows the ration calculation under the name of “PL”, which represents the passing or blockage behavior of SCC [
35].
Where, H
1 represents the heights of the concrete in the vertical section, while, H
2 measures at the end of the horizontal section, see
Figure 7. Nevertheless, the ECP 203 [
28] ranged this ratio between 0.8 to 1.0. The selected gate in this research was the one with two reinforcement rebars of spacing 59 mm to compile with the results of those in the J-ring slump flow test.
Then phase II, the specimens were dried in the laboratory and tested through various applied test equipment, as shown in
Figure 8. The test was typically handled on cube specimens during testing in compression into the universal testing machine of capacity 2000 kN for mechanical properties evaluation, see
Figure 8 – a. The cube specimens were tested at a pacing rate of 240 kg/cm
2 per minute according to EGP 203 [
28] until the specimens failed. While, prism specimens were tested at a pacing rate of 24 kg/cm
2 per minute by implementing compression loading on the prism specimens’ longitudinal direction, as shown in
Figure 8 – b. finally, cylinder specimens were tested in compression longitudinally at a pacing rate of 12 to 24 kg/cm
2 per minute as clarified in
Figure 8 – c for measuring splitting tensile strength. Recalling, the compressive strength was evaluated at 7 and 28 days of age while the flexural and splitting tensile strengths were measured at 28 days only.
Figure 1.
shows the sieve size grade distribution of coarse, fine, and glass aggregate.
Figure 1.
shows the sieve size grade distribution of coarse, fine, and glass aggregate.
Figure 2.
shows the curing tank for the specimens.
Figure 2.
shows the curing tank for the specimens.
Figure 3.
shows the slump flow diameter measurement.
Figure 3.
shows the slump flow diameter measurement.
Figure 4.
shows the slump flow of an engraved diameter of 500 mm at which the time is measured.
Figure 4.
shows the slump flow of an engraved diameter of 500 mm at which the time is measured.
Figure 5.
shows the J-ring with details of spacing and reinforcement diameter [
33].
Figure 5.
shows the J-ring with details of spacing and reinforcement diameter [
33].
Figure 6.
shows the V-funnel dimensions and the method of testing.
Figure 6.
shows the V-funnel dimensions and the method of testing.
Figure 7.
shows the L-box dimensions and the two sets of reinforcement spacing a) 41 mm, and b) 59 mm [
35].
Figure 7.
shows the L-box dimensions and the two sets of reinforcement spacing a) 41 mm, and b) 59 mm [
35].
Figure 8.
shows the testing of the cube, prism, and cylinder specimens for (a) compressive, (b) Flexural, and (c) Splitting tensile strengths.
Figure 8.
shows the testing of the cube, prism, and cylinder specimens for (a) compressive, (b) Flexural, and (c) Splitting tensile strengths.
Figure 9.
shows the slump flow measurement for the five mixes.
Figure 9.
shows the slump flow measurement for the five mixes.
Figure 10.
the slump T500 measurement for the five mixes.
Figure 10.
the slump T500 measurement for the five mixes.
Figure 11.
the J-ring measurement for the five mixes.
Figure 11.
the J-ring measurement for the five mixes.
Figure 12.
the V-funnel measurement for the five mixes.
Figure 12.
the V-funnel measurement for the five mixes.
Figure 13.
the V-funnel measurement after 5 minutes for the five mixes.
Figure 13.
the V-funnel measurement after 5 minutes for the five mixes.
Figure 14.
shows the measuring of the height H1 and H2 to determine the ratio for passability of the concrete mixture through L-box and spacing of reinforcement of 59 mm.
Figure 14.
shows the measuring of the height H1 and H2 to determine the ratio for passability of the concrete mixture through L-box and spacing of reinforcement of 59 mm.
Figure 15.
the L-box measurement for the five mixes.
Figure 15.
the L-box measurement for the five mixes.
Figure 16.
Compressive strength of cube specimens for the five mixes at 7 and 28 days.
Figure 16.
Compressive strength of cube specimens for the five mixes at 7 and 28 days.
Figure 17.
Flexural strength of the prism specimens for the five mixes at 28 days.
Figure 17.
Flexural strength of the prism specimens for the five mixes at 28 days.
Figure 18.
Splitting tensile strength of the cylinder specimens for the five mixes at 28 days.
Figure 18.
Splitting tensile strength of the cylinder specimens for the five mixes at 28 days.
Table 1.
shows the mix design and the portion of SCC ingredients.
Table 1.
shows the mix design and the portion of SCC ingredients.
Mix Code |
Designation |
Water (kg/ m3) |
Cement (kg/m3) |
CWP. (kg/m3) |
CA. (kg/m3) |
FA. (kg/m3) |
RG. (kg/m3) |
Control |
100% C + 100% FA |
231 |
550 |
- |
612 |
909 |
0 |
Mix 1 |
20% CWP + 5% RG |
231 |
440 |
110 |
612 |
863.55 |
45.45 |
Mix 2 |
20% CWP + 15% RG |
231 |
440 |
110 |
612 |
772.65 |
136.35 |
Mix 3 |
15% CWP + 10% RG |
231 |
467.5 |
82.5 |
612 |
818.1 |
90.9 |
Mix 4 |
25% CWP + 10% RG |
231 |
412.5 |
137.5 |
306 |
818.1 |
90.9 |
CWP: Ceramic Waste Powder; CA: Coarse Aggregate; FA: Fine Aggregate; RG: Recycled Glass |
Table 2.
shows the chemical composition.
Table 2.
shows the chemical composition.
Materials |
Cement |
Ceramic powder (CWP.) |
Glass (RG.) |
SiO2
|
25.3 |
63.9 |
81.98 |
Al2O3
|
6.64 |
18.29 |
0.86 |
Fe2O3
|
6.68 |
4.32 |
0.23 |
CaO |
58.44 |
4.46 |
10.67 |
MgO |
2.29 |
0.72 |
5.63 |
P2O5
|
0 |
0.16 |
0.12 |
K2O |
0.25 |
2.18 |
0.23 |
Na2O |
0.66 |
0.75 |
- |
SO3
|
2.04 |
0.1 |
0.19 |
Cl |
0.06 |
0.005 |
- |
TiO2
|
- |
0.61 |
- |
SrO2
|
- |
0.02 |
- |
Mn2O3
|
- |
0.05 |
- |
LOI |
4 |
1.61 |
- |
Table 3.
Upper and lower limits of the rheological tests on SCC as Per ECP 203 [
28].
Table 3.
Upper and lower limits of the rheological tests on SCC as Per ECP 203 [
28].
The rheological test |
Units |
Limits |
Min. |
Max. |
Slump Flow (diameter) |
mm |
600 |
800 |
Time for reaching slump flow with a diameter of 500 mm (T50 cm) |
sec. |
2 |
5 |
J-ring slump flow (diameter) |
mm |
0 |
20 |
V-funnel after immediate mixing (to) |
sec |
6 |
12 |
V-funnel after 5 minutes from mixing (t5min.)
|
sec |
to
|
to + 3 |
L-box (H2/H1) |
ratio |
0.80 |
1.0 |