Influence of Various Heat Treatment Regimes on Properties of Concrete Incorporating Marble Waste Powder as Cement Replacement

Over several decades, concrete has been considered as the most widely used materials in construction. However, its strength and durability can be affected by various environmental factors such as temperature and humidity. To enhance the mechanical properties of concrete, various thermal treatment methods have been developed [1].

It was demonstrated that concrete specimens subjected to an early high temperature of 40℃ had higher initial strength by 72.73% compared to concrete cured at 20℃, but exhibited lower strength at later stage. Conversely, specimens subjected to early low temperature (5℃) show lower initial strength but develop aging resistance almost equivalent to that of specimens subjected to isothermal curing (20℃) [2]. Kim et al. [3] investigated the effect of curing temperature, aging, and cement type on concrete mechanical properties. They found that concrete exposed to high temperature during early curing stages exhibited higher compression and flexural strength at early age but lower compression and flexural strength at older age. The curing temperature effect on the modulus of elasticity was not as significant as on the compression strength. This trend was also observed by Topcu and Toprak [4]. Singh et al. [5] conducted a technical study aimed to increasing the curing rate of concrete. They concluded that high-temperature curing of concrete was highly beneficial, while the acceleration through the use of accelerators admixtures can lead to many potential problems and difficulties. Hwang et al. [6] demonstrated a significant advantage of steam curing at 60℃. Through this method, concrete can develop compression strength six times higher than the same concrete when it was cured for 18 hours at 60℃. Liu et al. [7] found that steam curing thermal treatment of concrete at 60℃ increased the capillary absorption and concrete sorptivity coefficient. Zeyad et al. [8] found that thermal treatment of concrete at a temperature exceeding 80℃ has a negative influence on the microstructure and strength of concrete at long-term. Liu et al. [9] investigated the concrete mechanical properties modified with fly ash and subjected to steam curing at high temperatures of 60℃. They reported that for 13 hours of curing, concrete with fly ash exhibited low compressive strength by 19.08% at early age and after 28 days. Gesoglu [10] studied the influence of steam curing acceleration at 70℃ on concrete incorporating metakaolin and silica fume. He found that steam-cured concrete at high temperatures showed higher compression strength at an early age by 10%, while from 7 days onward, this concrete showed lower strength. Jacquemot et al. [11] studied the effect of temperature treatment on self-compacting concrete properties. They observed that high-temperature curing at 65℃ had a positive effect on the compressive strength which increased by 23.08% at 28 days. Bingöl and Tohumcu [12] found that steam treatment of self-compacting concrete incorporating silica fume and fly ash at 70℃ for 16 hours can achieve compression strength equivalent to 95% of that of standard cured concrete samples. Derabla and Benmalek [13] studied the behavior of self-compacting concrete thermally treated and modified with granulated slag, fine limestone, and crystallized slag. They found that the effect of thermal treatment at 60℃ for 24 hours was very pronounced at early age, as all thermally treated self-compacting concretes achieved higher strength by 156% than untreated self-compacting concretes. However, a minimal strength loss by 32% was observed in the long term. Ramezanianpour et al. [14] demonstrated that the increase in the initial compressive strength of self-compacting concrete thermally treated at 60-70℃ was accompanied by an increase in the permeability. Derabla and Sajed [15] studied the properties of self-compacting mortar thermally treated at 60℃. They found that the thermal treatment can improve the compressive strength. Additionally, they observed that the incorporation of limestone filler and ground granulated blast furnace slag enhanced the durability of self-compacting mortar subjected to thermal treatment. Kang et al. [16] studied the effect of thermal treatment on high-performance concrete. They found that this treatment method had a positive effect on the hydration of such concrete. They also observed that thermal treatment at high temperatures ensures exceptional strength at early age. However, there was no increase in long-term strength; instead, a slight decrease was observed. Moreover, long-term flexural and tensile strengths were similar regardless of curing conditions. Similar finding was noted by Fladr and Broukalova [17]. Shen et al. [18] added that the pores in high-performance concrete increased when it was exposed to thermal treatment. Mo et al. [19] found that steam thermal treatment increased the compressive strength at early age and significantly improved the reaction of metakaolin in the matrix of ultra-high-performance concrete. Stind et al. [20] found that increasing thermal treatment time to 24 hours reduced the shrinkage stresses of high-performance concrete. Zeyad et al. [21] and Rahimov and Muminov [22] studied the influence of thermal treatment on the properties of high-strength concrete containing varying amounts of ultrafine palm oil fuel ash. They found that this treatment was beneficial only at early age.

On the other hand, several researchers worked on the incorporation of industry waste in concrete composition to reduce the higher consumption of natural resources. Marble waste (MW) was subjected to several studies during the last decade [23] to investigate the possibility of its use as powder or aggregates. Djebien et al. [24] found that adding marble waste powder (MWP) to sand concrete composition significantly improved its workability. This trend was also observed by Rashwan et al. [25], who used MWP as a partial substitute for cement. This trend was explained by the fact that MWP minimize the friction between the constituents and facilitates concrete flow. Pal et al. [26] substituted cement with MWP, finding that compressive strength increased with increasing MWP content up to an optimal value corresponding to 10%. The gain in compressive strength was 8.54% and 12.84% at 7 and 28 days, respectively. This trend was observed and explained by the filling effect of MWP which increases concrete compactness [27, 28]. Rana et al. [29] observed that adding MWP to concrete composition reduced compressive strength values regardless of the MWP content. This reduction becomes significant when the substitution rate exceeds 10%. Topçu et al. [30] used MWP in self-compacting concrete formulation, concluding that MWP significantly reduced compressive strength when the substitution rate exceeded 200 kg/m³. Djebien et al. [31] studied the incorporation of MW as fine aggregate in self-compacting concrete formulation. They observed that the introduction of MW as sand decreased the air content and reduced the compressive strength. Tennich et al. [32] introduced MWP in concrete composition by substituting cement, noticing a decrease in the modulus of elasticity. Hameed and Sekar [33] studied the durability of MWP-based concrete, noting that concrete modified with MWP had higher sulfate ions resistance than concrete without MWP. Binici et al. [34] found that adding MWP to concrete composition improved concrete resistance to sulfate ions and reduced chloride ions penetration. Ince et al. [35] observed that MWP-based concretes had good resistance to freeze-thaw phenomenon. Monica and Dhoka [36] noted that water absorption of concrete modified with MW is slightly higher than that of ordinary concrete.

In this experimental work, Portland cement CEM II 42.5 (PC) was used. Tables 1 and 2 show the properties of cement used. This cement was used by Djebien et al. [23]. Crushed limestone fine aggregate (CFA) with a maximum nominal size of particles of 4 mm was used in this study as sand (CS). As coarse aggregates (CCA), two gravels (G1 and G2) having nominal size of 16 mm and 25 mm were used, respectively.

The properties of the CFA and CCA are presented in Table 3. Furthermore, Figure 1 depicts the particle size distribution of aggregates used.

Marble powder (MWP) was collected in wet form from the marble quarry of Skikda (Eastern Algeria), and was prepared by air drying followed by oven drying at 105℃, to obtain finely ground dry powder with a specific surface of 2608 cm²/g and a particle size less than 80 µm. Table 2 shows the chemical composition of MWP [23]. A superplasticizer (SP) based on poly-carboxylate was used. This was POLYFLOW SR 5400 having brown color, a pH of 5, and a density of 1.07.

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Figure 1. Particles size distribution of aggregates

Table 1. Properties of PC [23]

Table 2. Chemical composition of PC and MWP [23]

Table 3. Properties of aggregates

Table 4. Concrete mixtures

The Dreux-Gorisse method was used for the composition of control concrete (MC). Then, a substitution of 6% (CMW6), 12% (CMW12), and 18% (CMW18) of the total PC volume with MWP was carried out, without changing the content of CCA, CFA, water, and SP, which were remained constant (Table 4). These substitution rates of MWP were selected based on the previous studies which noted that a substitution rate not exceeding 10-15% does not significantly affect the compressive strength of concrete. The SP content was 1% of the cement weight. The solid ingredients were mixed for three minutes to ensure the homogeneity of mixtures. Then, superplasticizer and water were added and mixed for other three minutes with the other constituents according to NF P18-405.

The fresh mixtures were poured and vibrated into molds with dimensions of (150×150×150 mm³), (100×100×100 mm³), and (70×70×280 mm³). After placing the fresh concrete into the molds and vibrating it, the samples are positioned in a curing oven at designated temperatures for varying durations. The curing temperature was set at three levels, 45℃, 65℃, and 85℃, and the curing durations for these temperatures were set at 24 hours and 48 hours, respectively. After the end of the curing period, the samples were demolded and kept in a water basin at a temperature of 25℃ until the test date.

The cube samples of (150×150×150 mm³) were used for water absorption, ultrasonic pulse velocity, and compressive strength tests in accordance with NF EN 12390-3, NF EN 12504-4, and NBN B 15-215 standards, respectively. The prismatic samples of (70×70×280 mm³) were used for flexural strength according to NF EN 12390-5 standard. The cubic samples of (100×100×100 mm³) were used for durability tests using ASTMC 267-96 standard. After the initial thermal treatment, the specimens continued their mature in a water basin maintained at a temperature of 25℃. After 28 days of curing, the samples of durability tests were divided into two distinct groups, and then immersed in containers containing chemical solutions, namely hydrochloric acid (HCl) and sulfuric acid (H₂SO₄) with a concentration of 5%. The samples remained in these containers until the test days at 56 days, 90 days, and 180 days. A pH meter was used to monitor the pH level weekly.