Study of the use of LC<sup>3</sup> cements containing different calcined clays and fillers

Moreira, Gabriela; Souza, Ariel Miranda de; Elói, Fernanda Pereira da Fonseca; Silva, Guilherme Jorge Brigolini; Oliveira, Diogo Silva de; Carvalho, José Maria Franco de

doi:10.1590/s1678-86212025000100859

Abstract

To mitigate CO₂ emissions from cement production, supplementary cementitious materials (SCMs) are increasingly being explored as substitutes for Portland Cement (PC), such as calcined clay, a key component of LC³ (calcined limestone clay cement). This study evaluates the properties of LC³ mortars, in fresh and hardened state, using three types of calcined clays with different kaolinite contents and replacing the limestone filler with ornamental stone residues (OSW) to improve workability and eco-efficiency. The mortars were mechanically tested in both states and their eco-efficiency was evaluated. The compressive strength of calcined clay mortars decreased from 10% to 55% compared to the reference, except for the clay mixture with 72% kaolinite. The flexural strength decreased from 8% to 28%. Blends with OSW showed better results than those with limestone, improving compressive strength by up to 36% and reducing porosity through pore refinement. LC³ demonstrates greater eco-efficiency than traditional cement, despite slight reductions in mechanical strength.

Keywords
LC³; Sustainability; Ornamental stone waste; Calcined clay; Filler effect; Kaolinite content

Resumo

Para mitigar as emissões de CO₂ provenientes da produção de cimento, explora-se cada vez mais materiais cimentícios suplementares (SCMs) como substitutos do Cimento Portland (PC), como a argila calcinada, uma componente chave do LC³ (cimento de argila calcária calcinada). Este estudo avalia as propriedades das argamassas de LC³, em estado fresco e endurecido, utilizando três tipos de argilas calcinadas com diferentes teores de caulinita e substituindo o fíler calcário por resíduos de rochas ornamentais (OSW) para melhorar a trabalhabilidade e a ecoeficiência. As argamassas foram testadas mecanicamente em ambos os estados e sua ecoeficiência foi avaliada. A resistência à compressão das argamassas de argila calcinada diminuiu de 10% a 55% em comparação com a referência, exceto para a mistura de argila com 72% de caulinita. A resistência à flexão diminuiu de 8% a 28%. As misturas com OSW mostraram melhores resultados do que aquelas com calcário, melhorando a resistência à compressão em até 36% e reduzindo a porosidade através do refinamento dos poros. O LC³ demonstra maior ecoeficiência do que o cimento tradicional, apesar de ligeiras reduções na resistência mecânica.

Palavras-chave
LC³; Sustentabilidade; Resíduo de rocha ornamental; Argila calcinada; Efeito fíler; Teor de caulinita

Introduction

The cement industry is responsible for approximately 3% of global greenhouse gas emissions and approximately 5% of CO₂ emissions, making it one of the most polluting industries in the world (Huang et al., 2018). Utilizing Supplementary Cementitious Materials (SCMs) to mitigate the environmental impact of civil construction stands out as one of the most effective alternatives. SCMs possess cementing properties and exhibit characteristics akin to Portland Cement, both in their fresh and hardened states. However, the primary mineral additions such as blast furnace slag and fly ash are not abundantly available, consequently failing to meet the soaring demand for cement in the market (Scrivener et al., 2018). Enter LC³ (Limestone Calcined Clay Cement), a promising alternative comprising cement, calcined clay, and limestone filler – materials readily available in abundance – LC³ offers a solution capable of meeting the significant demand for cement while achieving comparable strength to Ordinary Portland Cement (OPC).

Numerous studies have been conducted to elucidate the composition of LC³, particularly concerning the constituents of LC² (Calcined Clay and Limestone). While traditional clinker comprises a blend of limestone and clay subjected to high-temperature calcination, LC² incorporates limestone solely as a filler, without undergoing calcination, while the clay undergoes lower-temperature calcination, resulting in lower greenhouse gas emissions. However, LC² contains a higher proportion of calcined clay compared to limestone, differing from the traditional clinker composition where the proportion of limestone is higher than that of calcined clay. This variation leads to unique effects on the hydration process and rheological properties of the cement (Santis; Rossignolo, 2014). The reactivity and fluidity of LC² are intimately tied to the type of clay, particularly concerning its morphology, water absorption characteristics, crystalline structure, and hydration properties (Balasubramanian; Sarangapani, 2023). Clays directly affect workability based on their specific characteristics, such as mineralogical composition, specific surface area, particle size, temperature, and even the type and amount of polycarboxylate-based superplasticizer used to achieve proper dispersion (Ribeiro et al., 2024).

In a study by Zhu et al. (2022), compared to blast furnace slag and fly ash, the LC² mixture exhibited reduced workability in mortar flow due to the high water demand of clay. However, LC²’s particle size and enhanced reactivity led to improved long-term drying shrinkage and greater cementation efficiency, particularly evident at early stages (Zhu et al., 2022). Abdulqader et al. (2023) investigated replacing 30%, 50%, and 70% of OPC with three different calcined clays varying in kaolinite content. They observed a decrease in fluidity with increasing replacement and found that mechanical strength reached the target of 28 MPa at 28 days only with replacements up to 50%. Hay and Celik (2023) explored a low kaolinite content clay in replacement tests ranging from 40% to 50% of OPC. Their findings indicated a decrease in compressive strength with increasing OPC replacement, with similar porosity across mixtures. Muzenda et al. (2020) utilized calcined clay available in China in seven compositions with clinker and limestone to assess the rheological properties of the LC³ system. They observed that viscosity and mechanical strength increased with higher LC² content, plateauing between 30% and 45% (Muzenda et al., 2020). Marangu (2020) conducted tests with LC³ mortars at three water-to-binder ratios (w/b ratios: 0.50, 0.55, 0.60). The compressive strength of LC³ surpassed that of the reference mortar at later ages due to increased pozzolanic reactions over time, with optimal results achieved at a w/b ratio of 0.50. Marangu (2020) also noted a decrease in the porosity of LC³ cement compared to the reference mortar, attributed to the lower w/b ratio. Avet and Scrivener (2018) compared the kaolinite content in clays between hemispheres, finding an average kaolinite content of 35% in clays from South America. They also observed higher silica content (67.6%) compared to alumina (22.6%). The LC³ tests were conducted using 50% clinker, 30% calcined clay, and 15% limestone. The results showed that clays with lower kaolinite content exhibited greater porosity at early ages, which improved over time. Clays with around 40% kaolinite achieved mechanical strength similar to Ordinary Portland Cement (OPC) at 28 days (Avet; Scrivener, 2018).

Previous studies have highlighted the multifaceted impact of limestone addition, elucidating both its physical and chemical effects. These effects include filling action through dilution, shearing action, and particle packing, alongside the enhanced efficiency of limestone as a filler and its capacity to accelerate clinker hydration (Dhandapani et al., 2021). However, it is essential to note that these effects primarily stem from the presence of limestone as a filler. Consequently, further investigations are warranted to ascertain whether alternative inert materials, such as waste products, could viably replace limestone in LC³ formulations. Recent research has also explored the use of waste materials as partial substitutes in LC³ production, demonstrating significant environmental benefits, with reductions of approximately 41% in CO₂ equivalents (Spat Ruviaro et al., 2023).

Moreover, discrepancies in research findings largely arise from variances in clay minerals and components (Pinheiro et al., 2023). Therefore, a comprehensive study of the morphological, swelling, flocculation, and reactivity properties of diverse clays proximate to cement industries is imperative to assess their practical applicability.

Hence, this study aims to investigate the physical, mechanical, morphological, and rheological properties of LC³ cements made from three distinct clay types with kaolinite contents of 8%, 46%, and 72%, sourced from Ijaci-MG. In these cements, the limestone filler was replaced with ornamental stone waste. By assessing the applicability and sustainability of these LC³ variants as substitutes for cement, we aim to provide comprehensive insights into their viability as eco-friendly alternatives.

Experimental program

Materials characterization

The binder used was a High Early Strength Portland Cement (PC) from the Brazilian company Cimento Nacional (equivalent to ASTM type III). The conventional aggregate was a natural river sand (S) from the Viçosa region, Minas Gerais, Brazil, oven-dried and passed through a #30 (600 µm) sieve.

The fillers used were limestone and ornamental stone waste (OSW), both dried in an oven for 24 hours at 100ºC. The limestone filler (L), from the company Intercement, Ijaci-MG (Figure 1), underwent 5 repetitions of grinding with the following program: 3 minutes of grinding followed by 5 minutes of restoration, using 30 balls of 10 cm and 100 balls of 5 cm. The OSW from a company in Cachoeiro de Itapemirim, Espírito Santo, Brazil, underwent grinding in the Pulverisette 6 apparatus at 300 rpm for 5 minutes.

Figure 1
City of Ijaci, State of Minas Gerais

Three types of clays from the Ijaci – MG region were used, which were designated according to the kaolinite content. The kaolinite content, determined using dried and non-calcined clays, was obtained through the methodology proposed by Avet and Scrivener (2020). The kaolinite content is given by the mass loss during the dehydroxylation of kaolinite, which was obtained through thermogravimetric analysis (TGA) (DTG-60H Shimadzu thermal analyzer, from 25 ºC to 1100 ºC, with a step of 10 ºC/min and an inert N₂ atmosphere (50 ml/min)). The kaolinite content can be calculated using Equation 1:

w t %_{kaolinite} = \frac{w t_{400^{\circ} C} - w t_{600^{\circ} C}}{w t_{200^{\circ} C}} \times \frac{M_{kaolinite}}{2 M_{water}} \times 100

Eq. 1

Where:

is the kaolinite content;

is the sample mass after heating to 200 °C;

is the sample mass after heating to 400 °C;

is the sample mass after heating to 600 °C;

is the molecular weight of kaolinite (258,16 g mol^-1); and

is the molecular weight of water (18,02 g mol^-1).

The kaolinite content found was 8% in one clay, 46% in another, and 72% in the third, following the nomenclature from Avet et al. (2016). From this point forward, the clays will be identified as C8, C46 and C72, respectively.

The clays (Figure 2) were dried in an oven for 24h at a temperature of 100 ºC, passed through grinding in a ball mill, and sieved on a #200 sieve (75 µm). They were calcined at 800 ºC for 1h, after temperature increases of 10 ºC/min. This calcination temperature was chosen to ensure complete dehydroxylation of kaolinite and to get the highest pozzolanic potential of calcined clay (Alujas et al., 2015; Avet et al., 2016; Fernandez; Martirena; Scrivener, 2011). Homogenization was carried out by an additional grinding process.

Figure 2
Images of the three clays: (a) Clay with 8% kaolinite content, (b) Clay with 46% kaolinite content, and (c) Clay with 72% kaolinite content

Characterization tests were carried out on the collected materials comprising density according to NBR NM 52 (ABNT, 2009a), fineness index by the Blaine method according to NBR 16372 (ABNT, 2015), laser granulometry, and scanning electron microscopy (SEM). The chemical composition of the non-calcined clays, limestone and OSW was evaluated using the X-ray Fluorescence (XRF) technique (Epsilon 3X X-ray spectrometer). The material characterization results are presented in Table 1. The density of the materials is similar, except for cement, which has a density 20% higher than the average of the others. Consequently, there is a higher concentration of the other materials in volume, as the mixtures were dosed by mass.

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Table 1
Chemical and physical characterization of the materials

In terms of specific surface area, the C46 and C72 clays displayed higher areas per weight, whereas the C8 clay exhibited a specific area 76% lower than that of the C46. When comparing the particle size curves of the materials shown in Figure 3, the similarities among the clays suggest that the variance in specific areas is attributable to differences in the morphologies of their particles. C46 and C72 featured rougher surfaces capable of adsorbing more water than the C8 clay at the same particle size proportion. The morphology of the clays is confirmed by the electron microscopy (SEM) images shown in Figure 4. C46 and C72 clays have rough surfaces, with elongated particles, while C8 clay has smooth surfaces. The OSW and limestone also had smooth surfaces.

Figure 3
Particle size of calcined clays (C8, C46, C72), limestone (L), ornamental stone waste (OSW) and cement (PC)

Figure 4
SEM images of clays (C8, C46, C72), limestone (L) and ornamental stone waste (OSW) with magnifications of (a) 1.00 kx and (b) 4.00 kx

The microstructure of the OSW, non-calcined clays and calcined clays was evaluated by X-ray diffractometry (XRD) (Bruker D8 Discover diffractometer with CuKα radiation (λ = 1.5418 Å), working voltage of 40 kV, and electric current of 40 mA). Samples were scanned from 5° to 65° (2θ), with a step size of 0.05° and a cumulative time per step of 1 second. Figure 5 presents the XRD results of the calcined clays. The C72 and C46 clays exhibited amorphous phases represented by halos between 16º and 32º, indicating good pozzolanic activity. However, the C8 clay did not present amorphous halos, suggesting low pozzolanic activity, primarily due to its high silica and quartz content, and low alumina and kaolinite content, which may not adequately complement a mixture with OSW due to the similar composition of the two materials.

Figure 5
XRD spectra of (a) OSW and non-calcined clays, and (b) calcined clays at 800 ºC

Mortar characterization

The mortars produced were mixed and tested on a flow table according to NBR 16738 procedures (ABNT, 2019a), show in Figure 6. A mass materials ratio of 1:2 (Binder: sand) and a water-to-binder ratio of 0.6 were used. Mortars composed of limestone were referred to as LC³ (%), while those made from ornamental stone waste were designated WC³ (%). The percentages in brackets indicate the kaolinite content in the calcined clay used. The proportion of LC³/WC³ was 50% cement, 30% calcined clay, and 20% limestone or ornamental stone waste. The mortar for each mix was molded into 3 specimens measuring 4x4x16 cm and cured by immersion in water saturated with lime until the date of the test. The proportions of each mixture are presented in Table 2.

Figure 6
Mini slump equipment for flow table test

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Table 2
Mortar materials proportions – the brackets indicate the calcined kaolinite content of the calcined clay

A compressible packing test was carried out according to the methodology applied by Franco de Carvalho et al. (2019). For this, fresh mortar samples were added to a container of known volume in three layers, compacted with 30 blows of a standard hammer. The mass of the sample inside the container was measured and the packing density was calculated according to Equations 1 to 3:

V_{S} = \frac{M}{ρ_{w} u_{w} + Σ_{i = 1}^{n} ρ_{i} R_{i}}

Eq. 1

φ = \frac{V_{s}}{V}

Eq. 2

u = \frac{V - V_{s}}{V_{s}}

Eq. 3

Where:

V_s is the volume of solids;

M is the mass of the material inside the container;

ρ_w is the water density;

u_w is the volumetric water/fines ratio;

ρ_i is the density of material I;

R_i is the volumetric ratio of material i about fines (blend);

V is the volume of the container;

φ s the packing density; and

u is the void index.

Packing density results were compared to the modified Andreassen packing curve (Funk; Dinger, 1994), calculated by Equation 4:

CPFT (%) = 100 (\frac{D^{q} - D_{S}^{q}}{D_{L}^{q} - D_{S}^{q}})

Eq. 4

Where:

CPFT is the accumulated percentage of particles with a diameter smaller than D (in volume);

D is the particle size;

D_L is the diameter of the largest particle;

D_S is the diameter of the smallest particle; and

q is the distribution coefficient (q-value), which was set at 0.3 for mortars with normal fluidity (Ramal Junior et al., 2002; Sarkar, 2016; Vanderlei, 2004).

An ultrasonic pulse velocity (UPV) (Proceq Pundit Lab, P wave, frequency 54 kHz) test was conducted by NBR 8802 (ABNT, 2019b), NBR 15630 (ABNT, 2009b) and C597-16 (ASTM, 2016). The UPV test was performed on saturated samples. The dynamic modulus of elasticity (E_d) was calculated according to Equation 5:

E_{d} = V^{2} ρ \frac{(1 + v) (1 - 2 v)}{(1 - v)}

Eq. 5

Where:

ρ is the density (kg/m³);

v is the dynamic Poisson’s ratio (0.2); and

V is the ultrasonic pulse velocity (m/s) (ABNT, 2005a, 2009b).

Mechanical tests of compressive strength and flexural tensile strength in mortars were carried out by NBR 16738 (ABNT, 2019a), in which the two resulting halves of the 4x4x16 cm specimen submitted to the flexural tensile strength test were tested for compressive strength by NBR 16738 (ABNT, 2019a).

The prismatic specimens from the flexural tensile test were tested for absorption, void index and specific mass by NBR 9778 (ABNT, 2005b).

Eco-efficiency analysis

The eco-efficiency analysis of the mixtures was performed using the inventory, Global Warming Potential (GWP) indicator, and Greenhouse Gases Reduction (GGR) indicator proposed by Miranda de Souza et al. (2021). The collected inventory includes a life cycle analysis (LCA) of cement, limestone, ornamental stone waste, water, and sand. No complete LCA results were found for calcined clays. Therefore, the inventory of Salvi Malacarne et al. (2021) was used, incorporating LCA results of the LC³ composed of common calcined clay, and the Global Warming Potential (GWP) indicator results were decomposed to focus solely on calcined clay.

Although the inventory comprises other indicators, the lack of data in the LC³ inventory led to the utilization of only the indicator that accounts for the undesirable effects of CO₂ emissions. The quantification of kg CO₂ eq/m³ of each mixture was divided by the compressive strength of the mixture, to generate the GGR indicator. The kg CO₂ eq/kg of each constituent material is shown in Table 3.

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Table 3
Environmental impact of each material

Results and discussion

Fresh-state

Figure 7(a) displays the results of the flow table test and the water-to-binder ratios in volume for the mortars. All mixtures containing calcined clays demonstrated lower spreads compared to the reference mortar, indicating that all clays require greater water content than cement. LC³ (46%) and LC³ (72%) mixtures exhibited the smallest spreads, 40.67% and 31.71% smaller than that of the reference mixture, respectively. LC³ (8%) mixture showed a spread similar to that of the reference mixture, with only a 1.29% reduction.

Figure 7
Fresh state test results for (a) flow table and (b) packing density

An increase in spreading was observed in Figure 7(a) when limestone was replaced by OSW, reaching an increase of 10.66% for the WC³ (46%) mixture about the LC³ (46%) mixture, and an increase of 5.93% for the WC³ (72%) mixture compared to the LC³ (72%) mixture. OSW managed to improve the workability of calcined clays, mainly due to the smooth morphology of the particles, which, combined with the rough morphology and high specific surface of calcined clays, balanced the undesirable effects of clays on fluidity. Regarding siliceous clay, the OSW did not show a significant difference, leading the WC³ (8%) mixture to a 1.18% reduction in spreading compared to the LC³ (8%) mixture. This behavior is attributed to siliceous clay having a different morphology compared to other clays, with smoother surfaces and a smaller specific surface area. As a result, it exhibits less water adsorption, allowing the free water to increase the fluidity of the mixture.

Similar results of increased workability due to OSW were reported by Miranda de Souza et al. (2023), wherein the authors replaced cement with OSW in self-compacting micro-concrete and found greater workability in mixtures with higher concentrations of the waste. The authors attributed the behavior to the smooth surface of the OSW and its inert characteristic (Miranda de Souza et al., 2023).

Even though the water content of the mixtures is measured by mass with an equal proportion for all mixtures, the differences in the densities of the materials used can result in significant variations in the w/b ratio, thereby influencing the fluidity of the mixtures. Figure 7(a) shows that all calcined clay mixtures had a w/b ratio much lower than that of the reference mixture, with the WC³ (72%) mixture experiencing a reduction of 10.6% compared to REF. On the other hand, the difference in the w/b ratio in volume in the mixtures, especially those with OSW due to its lower specific mass about limestone, indicates that OSW managed to increase workability even with a lower proportion of water to the grains.

Figure 7(b) presents the results of packing density and void index in the fresh state. 8% kaolinite content clay exhibited the highest packing density and lowest void content, which, due to better workability, favored densification and reduced voids. The other clays showed similar results to each other and the reference mixture. The waste reduced packing in the C8 and C46 clays and increased the void content of these clays, leading to a positive outcome only when mixed with C72 clay.

The packing density results were compared with the modified Andreassen packing curve a (Funk; Dinger, 1994), as shown in Figure 8. The curves of the mixtures with waste and the reference mixture had a small deviation from the modified Andreassen curve, which explains this small different fresh-state packing density results.

Figure 8
Particle size distribution curves of the dry mixtures compared to the modified Andreassen curve for q = 0.3

Hardened state results

Figure 9(a) illustrates that all mixtures exhibited lower strength results than the reference mortar, except for the WC³ (72%) mixture, which exceeded the REF by 3%. Similarly, Boakye et al. (2023) observed strength improvement with age, particularly in mixtures where Portland cement is replaced by 20% and 30% calcined clay. However, these improvements were still insufficient to match the reference values. The LC³ (46%), WC³ (46%), and LC³ (72%) mixtures experienced decreases in compressive strength compared to the REF of 18%, 10%, and 24%, respectively. The LC³ (8%) and WC³ (8%) mixtures showed decreases of 55% and 49%, achieving only half the mechanical strength of the reference mixture at 28 days. This demonstrates that the 8% kaolinite content clay did not exhibit significant pozzolanic activity, as expected from the XRD results, which did not show amorphous halos. Therefore, C8 clay only contributed to a cement dilution effect, serving solely as a filler. However, it is recommended for future studies to evaluate mechanical strength at later ages to assess potential late-stage gains.

Figure 9
Mortars (a) compressive strength, and (b) flexural strength

Moreover, in general, mixtures containing waste showed more promising results than those containing limestone, significantly improving the strength of WC³ (46%), WC³ (8%), and WC³ (72%) mixtures by 10%, 14%, and 36%, respectively. These findings suggest that the OSW managed to promote pore refinement and increase nucleation points, leading to a filler effect, as observed in previous studies (Miranda de Souza et al., 2023). Therefore, in terms of compressive strength, the waste yielded positive results, demonstrating its viability in LC³ cement production.

Figure 9(b) depicts similar results among all LC³ mixtures, with a difference of 19% to 28% compared to the REF. Notably, the LC³ (72%) mixture showed better performance, with only an 8% decrease. These mechanical results in LC³ (72%), both in compression and in flexural tension, may be attributed to the higher kaolinite content in the clay. Unlike the compression results, the WC³ (8%) mixture achieved similar or even better flexural results compared to the LC³ (46%), WC³ (46%), and WC³ (72%) mixtures.

Malacarne et al. (2021) obtained similar results by characterizing four types of LC³ mortar, varying two clays (AR - with 35% kaolinite and CN - with 83% kaolinite) and two limestones (HLS - high purity and LLS - lower grade). The mortar proportions were 50% cement, 5% gypsum, 30% calcined clay, and 15% limestone, with a water-to-binder ratio of 0.48. Compression results at 28 days showed that the mortar with half-kaolinite clay yielded better results, but the mortars with low-grade clay reached 32.6 and 33.9 MPa, respectively, with the highest result obtained with the mixture containing low-grade limestone. Moreover, both mixtures exceeded the reference value of 22.7 MPa. Therefore, it can be concluded that clays with higher kaolinite contents yield better mechanical results.

However, considering the exploitation of kaolin in other industries, it is necessary to evaluate the feasibility of using other clays in LC³ composition, focusing on clays that are abundantly available near cement plants. In this study, 8% and 46% kaolinite content clays were found to be the most readily available near the cement industry, and 46% kaolinite content clay demonstrated high potential for LC³ composition.

Figure 10 presents the results of the physical characterization of the mortars, with results of absorption, void index and density. Compared to the REF mixture, the LC³ (8%) and WC³ (8%) mixtures obtained the best results of absorption and void index, which may be related to its morphological characteristics (smooth particles and lower specific surface) that allow the self-consolidation and reduction of voids.

Figure 10
Absorption, void index and density of mortars

The LC³ (46%) and WC³ (46%) mixtures exhibited a void index of 8.05% to 8.43% and absorption rates of 12.88% to 11.37% higher than the REF mixture. Similarly, the LC³ (72%) and WC³ (72%) mixtures surpassed the reference mortar by 5.6% to 1.48% in the void index and 10.13% to 8.07% in absorption.

Similarly, Frías et al. (2024) found absorption results indicating that mortars with 10% and 30% replacement content absorb more water than the reference mortar. This difference may be attributed to the varying network of capillary pores in the mixtures.

In general, mixtures containing OSW exhibited lower values for both absorption and void index. The LC³ (8%) mixture achieved the same value as the REF for void index, and the WC³ (8%) mixture showed a reduction of 2.55% and 2.77% in void index and absorption, respectively. This can be explained by the smoother surfaces of the OSW, which promote greater fluidity, filler effect, and pore refinement (Miranda de Souza et al., 2023).

Figure 11 presents the results of the ultrasonic pulse velocity (UPV) and dynamic elastic modulus of the samples. Compared to the REF mixture, all LC³ mixtures exhibited a UPV 7% to 12% lower. Among the LC³ mixtures, the WC³ (72%) mixture showed the highest UPV, while the WC³ (46%) mixture showed the lowest.

Figure 11
Ultrasonic pulse velocity (UPV) and dynamic modulus of elasticity of mortars

When comparing mixtures containing limestone and ornamental stone waste, it was observed that the addition of OSW decreased the UPV when combined with C8 and C46 clays, but increased the UPV when combined with C72 clay. These results are attributed to the porosity of the mixtures, with more porous structures leading to reduced wave speed.

Once again, attention is drawn to the UPV results of LC³ (8%) mixture. Despite having lower compressive strength, these mixtures presented a more refined and less porous structure compared to other clays, resulting in UPV values of 0.46%, 5%, and 4% higher than those of LC³ (46%), WC³ (46%), and LC³ (72%) mixtures, respectively. These differences are primarily due to the greater refinement of pores in the LC³ (8%) mixtures, which, although not increasing mechanical strength through pozzolanic reactions, achieved a filler effect by filling pores.

A decrease in UPV of LC³ with more than 25% calcined clay was also reported by Shamseldeen Fakhri and Thanon Dawood (2023). The authors observed an increase in UPV of LC³ with up to 20% calcined clay compared to the reference mixture, while mixtures with more than 25% calcined clay led to a decrease in UPV due to chemical reactions and pore formation. Astudillo et al. (2023) also observed decreases in UPV in all mixtures containing clay, whether calcined or not, which was attributed to the properties of kaolinite clays, porosity, and calcination conditions.

The dynamic modulus of elasticity of the samples, evaluated through UPV of the wet samples at 28 days, is illustrated in Figure 11. Similar to the UPV results, it is observed that the REF mixture obtained the highest modulus of elasticity, while the mixtures with LC³ showed decreases between 14% and 22% compared to REF. These results are explained by the porosity and mechanical strength of the samples.

Eco-efficiency analysis

Figure 12(a) displays the results of the Global Warming Potential (GWP) in kgCO₂ eq./m³ for each mortar, and Figure 12(b) displays the results of the Greenhouse Gases Reduction (GGR) indicator along with the compressive strength results for comparison.

Figure 12
(a) Global warming potential (GWP) and (b) Greenhouse Gases Reduction (GGR) indicator for the produced mortars

In Figure 12(a), it is evident that the mixtures containing LC³ and WC³ showed a reduction of up to 39% in CO₂ emissions per volume of mortar compared to the reference mixture, with a difference of less than 1% between the LC³ containing OSW and those containing limestone. Replacing limestone with OSW did not result in a significant change in greenhouse gas emissions. However, other indicators proposed by Miranda de Souza et al. (2021) should be examined to evaluate additional environmental aspects, especially regarding the use of recycled materials.

Figure 12(b) presents an indicator that evaluates the environmental impacts weighted by performance (compressive strength achieved by the mixture), with the index varying between 0 and 1. As LC³ mixtures generate equivalent CO₂ emissions, the indicator is influenced by mechanical strength. Higher mechanical strength results in a better index for LC³ mixtures. Thus, the WC³ (72%) mixture exhibited the highest eco-efficiency index, while the LC³ (8%) mixture showed the lowest eco-efficiency index.

However, although the mechanical strength of the LC³ (72%) mixture was 24% lower than the reference mixture, the LC³ (72%) mixture still presented a 51% higher index, which indicates that even with a drop in mechanical strength, the LC³ that achieves structural mechanical strength is more eco-efficient than PC.

To the REF mixture, the WC³ (72%) mixture had a 110% increase in eco-efficiency, while the WC³ (46%) and LC³ (46%) mixtures had an 87% and 68% increase in eco-efficiency, respectively. These results are similar to those found by Kanagaraj et al. (2023), who reported that the carbon efficiency of LC³ can be between 45% and 90% better than that of PC.

Cancio Diaz et al. (2019) also compared the eco-efficiency of LC³ with PC through energy consumption in a rotary kiln and Economic Value Added per carbon dioxide emission. The authors found an energy reduction of around 30% to 40% in the calcination of metakaolinite compared to PC. In cements with 45% replacement of PC by LC³, a 20% to 22% decrease in CO₂ emissions was found, while in cements with 60% replacement of PC by LC³, a 35% to 38% decrease in CO₂ emissions was observed, mainly due to the decrease in CO₂ generated during the calcination and transport phases (Cancio Diaz et al., 2019).

The values found by Cancio Diaz et al. (2019) are similar to those found in this work, where a 39% reduction in CO₂ emissions per volume of mortar was observed. These data show that LC³ has great potential to replace conventional cement. These data show that LC³ has great potential to replace conventional cement. It has been proven to emit lower CO₂, incorporate waste, reduce costs, and maintain mechanical characteristics similar to conventional cement.

Conclusion

This study aimed to examine the characteristics of three distinct calcined clays and how they perform in LC³ composites, using mortar tests. The results uncovered several important insights:

mortars with 8% kaolinite content in the clays used showed similar spreading results to the reference mortar. In contrast, those with 46% and 72% kaolinite content had rheological losses, partially offset by OSW. These results are linked to water consumption by volume. Portland Cement, with a higher specific mass, uses less volume, leaving more water for the cement grains. In contrast, LC³ mixtures have less water per grain due to their higher volume of materials;
clays with 8% kaolinite content demonstrated the best packing density, absorption and void index due to their morphological characteristics. OSW improved packing and reduced void index only when combined with clays of higher kaolinite content. All LC³ mortars showed better packing and lower void indices than the reference mortar;
all mixtures exhibited lower compressive and flexural strength than the reference mortar, except for the WC³ (72%) mixture, which exceeded the reference by 3% in compressive strength. The LC³ (8%) and WC³ (8%) mixtures showed significant decreases, achieving only half the strength of the reference at 28 days. Mixtures containing OSW performed better than those with limestone, improving compressive and flexural strength by 10% to 36%. This indicates that the OSW refined pores and increased nucleation points, enhancing the filler effect;
ultrasonic pulse velocity (UPV) results showed that all mixtures had lower wave speeds compared to the reference mixture. However, mixtures with 8% kaolinite content clay exhibited a more refined, less porous structure, resulting in higher UPV values; and
LC³ and WC³ made from clays with 46% and 72% kaolinite content are more eco-efficient than Portland Cement.

These findings underscore the potential of LC³ as a sustainable alternative in construction materials. Future research should further explore the optimization of water proportions in LC³ systems, evaluate mechanical strength at ages after 28 days, and conduct comprehensive life cycle analyses of calcined clays, both individually and within LC³ formulations, to better understand their environmental impact and enhance their applicability in construction practices.

References

ABDULQADER, M. et al. Physicochemical properties of limestone calcined clay cement (LC3) concrete made using Saudi clays. Journal of Materials Research and Technology, v. 25, p. 2769–2783, jul. 2023.
ALUJAS, A. et al. Pozzolanic reactivity of low grade kaolinitic clays: influence of calcination temperature and impact of calcination products on OPC hydration. Applied Clay Science, v. 108, p. 94–101, may 2015.
AMERICAN SOCIETY OF TESTING AND MATERIALS. C597: standard test method for pulse velocity through concrete. West Conshohocken, 2016.
ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 13280: argamassa para assentamento e revestimento de paredes e tetos: determinação da densidade de massa aparente no estado endurecido. Rio de Janeiro, 2005a.
ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 15630: argamassa para assentamento e revestimento de paredes e tetos: determinação do módulo de elasticidade dinâmico através da propagação de onda ultra-sônica. Rio de Janeiro, 2009b.
ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 16372: cimento Portland e outros materiais em pó: determinação da finura pelo método de permeabilidade ao ar (método de Blaine). Rio de Janeiro, 2015.
ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 16738: cimento Portland: determinação da resistência à compressão de corpos de prova prismáticos. Rio de Janeiro, 2019a.
ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 8802: concreto endurecido: determinação da velocidade de propagação de onda ultrassônica. Rio de Janeiro, 2019b.
ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 9778: argamassa e concreto endurecidos: determinação da absorção de água, índice de vazios e massa específica. Rio de Janeiro, 2005b.
ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR NM 52: agregado miúdo: determinação da massa específica e massa específica aparente. Rio de Janeiro, 2009a.
ASTUDILLO, B. et al. Improvement of the mechanical properties of mortars manufactured with partial substitution of portland cement by kaolinitic clays. Buildings, v. 13, n. 7, p. 1–16, 2023.
AVET, F. et al. Development of a new rapid, relevant and reliable (R3) test method to evaluate the pozzolanic reactivity of calcined kaolinitic clays. Cement and Concrete Research, v. 85, p. 1–11, 2016.
AVET, F.; SCRIVENER, K. Investigation of the calcined kaolinite content on the hydration of Limestone Calcined Clay Cement (LC3). Cement and Concrete Research, v. 107, n. February, p. 124–135, 2018.
AVET, F.; SCRIVENER, K. Simple and reliable quantification of kaolinite in clay using an oven and a balance. In: BISHNOI, S. (ed.). Calcined clays for sustainable concrete Singapore: Springer, 2020.
BALASUBRAMANIAN, N.; SARANGAPANI, C. A review on the factors influencing the performance of sustainable ternary cement composites. Environment, Development and Sustainability, v. 26, n. 10, ago. 2023.
BOAKYE, K. et al. Performance of a single source of low-grade clay in a limestone calcined clay cement mortar. Buildings, v. 14, n. 1, p. 93, dez. 2023.
CANCIO DIAZ, Y. et al Eco-efficiency assessment of conventional OPC/PPC replacement by LC3 in Cuban residential buildings. IOP Conference Series: Earth and Environmental Science, v. 323, n. 1, 2019.
DHANDAPANI, Y. et al. Towards ternary binders involving limestone additions: a review. Cement and Concrete Research, v. 143, n. February, p. 106396, 2021.
FERNANDEZ, R.; MARTIRENA, F.; SCRIVENER, K. L. The origin of the pozzolanic activity of calcined clay minerals: a comparison between kaolinite, illite and montmorillonite. Cement and Concrete Research, v. 41, n. 1, p. 113–122, 2011.
FRANCO DE CARVALHO, J. M. et al. More eco-efficient concrete: an approach on optimization in the production and use of waste-based supplementary cementing materials. Construction and Building Materials, v. 206, p. 397–409, 2019.
FRÍAS, M. et al. Viability of using limestone concrete waste from CDW to produce ternary cements type LC3. Construction and Building Materials, v. 411, p. 134362, jan. 2024.
FUNK, J. E.; DINGER, D. R. Particle size control for high-solids castable refractories. American Ceramic Society Bulletin, v. 73, p. 66–69, 1994.
HAY, R.; CELIK, K. Performance enhancement and characterization of limestone calcined clay cement (LC3) produced with low-reactivity kaolinitic clay. Construction and Building Materials, v. 392, p. 131831, ago. 2023.
HUANG, L. et al. Carbon emission of global construction sector. Renewable and Sustainable Energy Reviews, v. 81, p. 1906–1916, jan. 2018.
KANAGARAJ, B. et al. Techno-socio-economic aspects of Portland cement, Geopolymer, and Limestone Calcined Clay Cement (LC3) composite systems: a-state-of-art-review. Construction and Building Materials, v. 398, n. December 2022, p. 132484, 2023.
MALACARNE, C. S. et al. Influence of low-grade materials as clinker substitute on the rheological behavior, hydration and mechanical performance of ternary cements. Case Studies in Construction Materials, v. 15, 2021.
MARANGU, J. M. Physico-chemical properties of Kenyan made calcined Clay -Limestone cement (LC3). Case Studies in Construction Materials, v. 12, p. e00333, jun. 2020.
MIRANDA DE SOUZA, A. et al. Application of the desirability function for the development of new composite eco-efficiency indicators for concrete. Journal of Building Engineering, p. 102374, mar. 2021.
MIRANDA DE SOUZA, A. et al. Influence of filler/cement and powder/total solids on the mixture design of self-compacting micro-concretes containing waste from the ornamental stone industry. Construction and Building Materials, v. 407, n. June, p. 133445, dez. 2023.
MUZENDA, T. R. et al. The role of limestone and calcined clay on the rheological properties of LC3. Cement and Concrete Composites, v. 107, n. May 2019, p. 103516, 2020.
PINHEIRO, V. D. et al. Methods for evaluating pozzolanic reactivity in calcined clays: a review. Materials, v. 16, n. 13, 2023.
RAMAL JUNIOR, F. T. et al. A curva de distribuição granulométrica e sua influência na reologia de concretos refratários. Cerâmica, v. 48, n. 308, p. 212–216, 2002.
RIBEIRO, F. R. C. et al. Assessing hydration kinetics and rheological properties of Limestone Calcined Clay Cement (LC3): influence of clay-mitigating and superplasticizer admixtures. Case Studies in Construction Materials, v. 20, p. e03364, jul. 2024.
SALVI MALACARNE, C. et al. Environmental and technical assessment to support sustainable strategies for limestone calcined clay cement production in Brazil. Construction and Building Materials, v. 310, n. August, 2021.
SANTIS, B. C. de; ROSSIGNOLO, J. A. Avaliação da influência de agregados leves de argila calcinada no desempenho de concretos estruturais. Ambiente Construído, Porto Alegre, v. 14, n. 4, p. 21–32, out./dez. 2014.
SARKAR, R. Particle size distribution for refractory castables: a review. InterCeram: International Ceramic Review, v. 65, n. 3, p. 82–86, 2016.
SCRIVENER, K. L. et al. Calcined clay limestone cements (LC3). Cement and Concrete Research, v. 114, p. 49–56, 2018.
SHAMSELDEEN FAKHRI, R.; THANON DAWOOD, E. Limestone powder, calcined clay and slag as quaternary blended cement used for green concrete production. Journal of Building Engineering, v. 79, n. August, p. 107644, 2023.
SPAT RUVIARO, A. et al. Eco-efficient cement production: investigating water treatment plant sludge and eggshell filler use in LC3 systems. Construction and Building Materials, v. 394, p. 132300, ago. 2023.
VANDERLEI, R. D. Análise experimental do concreto de pós reativos: dosagem e propriedades mecânicas. São Carlos, 2004. Thesis - Escola de Engenharia de São Carlos, Universidade de São Paulo, São Carlos, 2004.
ZHU, H. et al. Low carbon and high efficiency limestone-calcined clay as supplementary cementitious materials (SCMs): multi-indicator comparison with conventional SCMs. Construction and Building Materials, v. 341, n. 100, p. 127748, 2022.

Edited by

Editor:
Enedir Ghisi

Editora de seção:
Ana Paula Kirchheim

Publication Dates

Publication in this collection
17 Mar 2025
Date of issue
Jan-Dec 2025

History

Received
02 May 2024
Accepted
13 Aug 2024

This is an Open Access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

[1] ABDULQADER, M. et al. Physicochemical properties of limestone calcined clay cement (LC3) concrete made using Saudi clays. Journal of Materials Research and Technology, v. 25, p. 2769–2783, jul. 2023.

[2] ALUJAS, A. et al. Pozzolanic reactivity of low grade kaolinitic clays: influence of calcination temperature and impact of calcination products on OPC hydration. Applied Clay Science, v. 108, p. 94–101, may 2015.

[3] AMERICAN SOCIETY OF TESTING AND MATERIALS. C597: standard test method for pulse velocity through concrete. West Conshohocken, 2016.

[4] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 13280: argamassa para assentamento e revestimento de paredes e tetos: determinação da densidade de massa aparente no estado endurecido. Rio de Janeiro, 2005a.

[5] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 15630: argamassa para assentamento e revestimento de paredes e tetos: determinação do módulo de elasticidade dinâmico através da propagação de onda ultra-sônica. Rio de Janeiro, 2009b.

[6] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 16372: cimento Portland e outros materiais em pó: determinação da finura pelo método de permeabilidade ao ar (método de Blaine). Rio de Janeiro, 2015.

[7] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 16738: cimento Portland: determinação da resistência à compressão de corpos de prova prismáticos. Rio de Janeiro, 2019a.

[8] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 8802: concreto endurecido: determinação da velocidade de propagação de onda ultrassônica. Rio de Janeiro, 2019b.

[9] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR 9778: argamassa e concreto endurecidos: determinação da absorção de água, índice de vazios e massa específica. Rio de Janeiro, 2005b.

[10] ASSOCIAÇÃO BRASILEIRA DE NORMAS TÉCNICAS. NBR NM 52: agregado miúdo: determinação da massa específica e massa específica aparente. Rio de Janeiro, 2009a.

[11] ASTUDILLO, B. et al. Improvement of the mechanical properties of mortars manufactured with partial substitution of portland cement by kaolinitic clays. Buildings, v. 13, n. 7, p. 1–16, 2023.

[12] AVET, F. et al. Development of a new rapid, relevant and reliable (R3) test method to evaluate the pozzolanic reactivity of calcined kaolinitic clays. Cement and Concrete Research, v. 85, p. 1–11, 2016.

[13] AVET, F.; SCRIVENER, K. Investigation of the calcined kaolinite content on the hydration of Limestone Calcined Clay Cement (LC3). Cement and Concrete Research, v. 107, n. February, p. 124–135, 2018.

[14] AVET, F.; SCRIVENER, K. Simple and reliable quantification of kaolinite in clay using an oven and a balance. In: BISHNOI, S. (ed.). Calcined clays for sustainable concrete Singapore: Springer, 2020.

[15] BALASUBRAMANIAN, N.; SARANGAPANI, C. A review on the factors influencing the performance of sustainable ternary cement composites. Environment, Development and Sustainability, v. 26, n. 10, ago. 2023.

[16] BOAKYE, K. et al. Performance of a single source of low-grade clay in a limestone calcined clay cement mortar. Buildings, v. 14, n. 1, p. 93, dez. 2023.

[17] CANCIO DIAZ, Y. et al Eco-efficiency assessment of conventional OPC/PPC replacement by LC3 in Cuban residential buildings. IOP Conference Series: Earth and Environmental Science, v. 323, n. 1, 2019.

[18] DHANDAPANI, Y. et al. Towards ternary binders involving limestone additions: a review. Cement and Concrete Research, v. 143, n. February, p. 106396, 2021.

[19] FERNANDEZ, R.; MARTIRENA, F.; SCRIVENER, K. L. The origin of the pozzolanic activity of calcined clay minerals: a comparison between kaolinite, illite and montmorillonite. Cement and Concrete Research, v. 41, n. 1, p. 113–122, 2011.

[20] FRANCO DE CARVALHO, J. M. et al. More eco-efficient concrete: an approach on optimization in the production and use of waste-based supplementary cementing materials. Construction and Building Materials, v. 206, p. 397–409, 2019.

[21] FRÍAS, M. et al. Viability of using limestone concrete waste from CDW to produce ternary cements type LC3. Construction and Building Materials, v. 411, p. 134362, jan. 2024.

[22] FUNK, J. E.; DINGER, D. R. Particle size control for high-solids castable refractories. American Ceramic Society Bulletin, v. 73, p. 66–69, 1994.

[23] HAY, R.; CELIK, K. Performance enhancement and characterization of limestone calcined clay cement (LC3) produced with low-reactivity kaolinitic clay. Construction and Building Materials, v. 392, p. 131831, ago. 2023.

[24] HUANG, L. et al. Carbon emission of global construction sector. Renewable and Sustainable Energy Reviews, v. 81, p. 1906–1916, jan. 2018.

[25] KANAGARAJ, B. et al. Techno-socio-economic aspects of Portland cement, Geopolymer, and Limestone Calcined Clay Cement (LC3) composite systems: a-state-of-art-review. Construction and Building Materials, v. 398, n. December 2022, p. 132484, 2023.

[26] MALACARNE, C. S. et al. Influence of low-grade materials as clinker substitute on the rheological behavior, hydration and mechanical performance of ternary cements. Case Studies in Construction Materials, v. 15, 2021.

[27] MARANGU, J. M. Physico-chemical properties of Kenyan made calcined Clay -Limestone cement (LC3). Case Studies in Construction Materials, v. 12, p. e00333, jun. 2020.

[28] MIRANDA DE SOUZA, A. et al. Application of the desirability function for the development of new composite eco-efficiency indicators for concrete. Journal of Building Engineering, p. 102374, mar. 2021.

[29] MIRANDA DE SOUZA, A. et al. Influence of filler/cement and powder/total solids on the mixture design of self-compacting micro-concretes containing waste from the ornamental stone industry. Construction and Building Materials, v. 407, n. June, p. 133445, dez. 2023.

[30] MUZENDA, T. R. et al. The role of limestone and calcined clay on the rheological properties of LC3. Cement and Concrete Composites, v. 107, n. May 2019, p. 103516, 2020.

[31] PINHEIRO, V. D. et al. Methods for evaluating pozzolanic reactivity in calcined clays: a review. Materials, v. 16, n. 13, 2023.

[32] RAMAL JUNIOR, F. T. et al. A curva de distribuição granulométrica e sua influência na reologia de concretos refratários. Cerâmica, v. 48, n. 308, p. 212–216, 2002.

[33] RIBEIRO, F. R. C. et al. Assessing hydration kinetics and rheological properties of Limestone Calcined Clay Cement (LC3): influence of clay-mitigating and superplasticizer admixtures. Case Studies in Construction Materials, v. 20, p. e03364, jul. 2024.

[34] SALVI MALACARNE, C. et al. Environmental and technical assessment to support sustainable strategies for limestone calcined clay cement production in Brazil. Construction and Building Materials, v. 310, n. August, 2021.

[35] SANTIS, B. C. de; ROSSIGNOLO, J. A. Avaliação da influência de agregados leves de argila calcinada no desempenho de concretos estruturais. Ambiente Construído, Porto Alegre, v. 14, n. 4, p. 21–32, out./dez. 2014.

[36] SARKAR, R. Particle size distribution for refractory castables: a review. InterCeram: International Ceramic Review, v. 65, n. 3, p. 82–86, 2016.

[37] SCRIVENER, K. L. et al. Calcined clay limestone cements (LC3). Cement and Concrete Research, v. 114, p. 49–56, 2018.

[38] SHAMSELDEEN FAKHRI, R.; THANON DAWOOD, E. Limestone powder, calcined clay and slag as quaternary blended cement used for green concrete production. Journal of Building Engineering, v. 79, n. August, p. 107644, 2023.

[39] SPAT RUVIARO, A. et al. Eco-efficient cement production: investigating water treatment plant sludge and eggshell filler use in LC3 systems. Construction and Building Materials, v. 394, p. 132300, ago. 2023.

[40] VANDERLEI, R. D. Análise experimental do concreto de pós reativos: dosagem e propriedades mecânicas. São Carlos, 2004. Thesis - Escola de Engenharia de São Carlos, Universidade de São Paulo, São Carlos, 2004.

[41] ZHU, H. et al. Low carbon and high efficiency limestone-calcined clay as supplementary cementitious materials (SCMs): multi-indicator comparison with conventional SCMs. Construction and Building Materials, v. 341, n. 100, p. 127748, 2022.

Properties	PC	Non-calcined clays			L	OSW
Properties	PC	C8	C46	C72	L	OSW
Kaolinite content. %	-	8%	46%	72%	-	-
SiO₂ content. %	-	72.1	24.5	38.9	3.62	74.5
Al₂O₃ content. %	-	16.2	39.5	36.6	1.44	5.3
Fe₂O₃ content. %	-	3.0	11.7	6.3	0.3	-
SO₃ content %	3.60
CaO content. %	-	0.5	0.4	0.4	92.8	5.0
MgO content. %	1.75	-	-	-	0.64	3.5
K₂O content. %	0.75	2.7	0.2	0.3	0.11	-
TiO₂ content. %	-	0.4	2.1	1.6	-	-
Other oxides (< 2%). %	-	1.7	0.3	0.5	0.14	3.6
LOI content. %	4.94	3.4	21.7	14.8	-	8.1
Specific density (g/cm³)	3.15	2.69	2.60	2.53	2.73	2.60
Specific surface area (cm²/g)	2135.81	1398.74	5785.09	5464.04	1345.89	2996.11

Mix	PC	Calcined Clay	Limestone	OSW	Sand	Water
REF	496.19	-	-	-	992.39	297.72
LC³ (8%)	248.10	148.86 (8%)	99.24	-	992.39	297.72
WC³ (8%)	248.10	148.86 (8%)	-	99.24	992.39	297.72
LC³ (46%)	248.10	148.86 (46%)	99.24	-	992.39	297.72
WC³ (46%)	248.10	148.86 (46%)	-	99.24	992.39	297.72
LC³ (72%)	248.10	148.86 (72%)	99.24	-	992.39	297.72
WC³ (72%)	248.10	148.86 (72%)	-	99.24	992.39	297.72

Study of the use of LC³ cements containing different calcined clays and fillers

Estudo da utilização de cimentos LC³ contendo diferentes argilas calcinadas e fíleres

Abstract

Resumo

Introduction

Experimental program

Materials characterization

Mortar characterization

Eco-efficiency analysis

Results and discussion

Fresh-state

Hardened state results

Eco-efficiency analysis

Conclusion

References

Edited by

Publication Dates

History

Study of the use of LC3 cements containing different calcined clays and fillers

Estudo da utilização de cimentos LC3 contendo diferentes argilas calcinadas e fíleres

Abstract

Resumo

Introduction

Experimental program

Materials characterization

Mortar characterization

Eco-efficiency analysis

Results and discussion

Fresh-state

Hardened state results

Eco-efficiency analysis

Conclusion

References

Edited by

Publication Dates

History

Study of the use of LC³ cements containing different calcined clays and fillers

Estudo da utilização de cimentos LC³ contendo diferentes argilas calcinadas e fíleres