Self-compacting Concrete Samples Research Articles

Performance Evaluation of Self-Compacting Glass Fiber Concrete Incorporating Silica Fume at Elevated Temperatures

In this work, the properties of self-compacting concrete (SCC) and SCC containing 0.5 and 1% glass fibers (with lengths of 6 and 13 mm) were experimentally investigated, as well as their performance at high temperatures. With a heating rate of 5 °C/min, high-temperature experiments were conducted at 200, 400, 600, and 800 °C to examine mass loss, spalling, and the remaining mechanical properties of SCC with and without glass fibers. According to the results of the flowability and passing ability tests, adding glass fibers does not affect how workable and self-compacting SCCs were. These findings also demonstrated that the mechanical properties of samples with and without glass fibers rose up to 200 °C but then decreased at 400 °C, whereas the mixture containing 0.5% glass fibers of a length of 13 mm displayed better mechanical properties. Both SCC samples with and without glass fibers remained intact at 200 °C. Some SCC samples displayed some corner and edge spalling when the temperature reached about 400 °C. Above 400 °C, a significant number of microcracks started to form. SCC samples quickly spalled and were completely destroyed between 600 and 800 °C. According to the results, glass fibers cannot stop SCC from spalling during a fire. Between 200 and 400 °C, there was no discernible mass loss. At 600 °C, mass loss starts to accelerate quickly, and it increased more than ten times beyond 200 °C. The ultrasonic pulse velocity (UPV) of SCC samples with glass fibers increased between room temperature and 200 °C, and the mixture containing 0.5% glass fibers of a length of 13 mm showed a somewhat higher UPV than other SCC mixtures until it started to decline at about 400 °C.

Influence of recycled steel fiber on the properties of self-compacting concrete with high fly ash content


 
 
 The recycled steel fibers from waste steel cables have properties suitable for enhancing the load-bearing capacity, impact resistance, and shrinkage reduction of Self-Compacting Concrete (SCC). The use of a high content of fly ash in SCC reduces production costs and is environment friendly by minimizing the amount of cement in the mix. This article presents the experimental research results on the influence of the content of recycled steel fibers on the properties of high-fly-ash SCC. The research utilized recycled steel fibers from elevator steel cables with volume percentages of 0%, 0.5%, 1% and 1.5% respectively in SCC, with a fly ash content in the SCC mix of 50% by volume of powder. The evaluated properties included workability, plastic shrinkage, drying shrinkage compressive strength, and tensile strength. The results indicate that using recycled steel fibers with a maximum content of 1% enables the production of SCC that meets European standards for workability. In addition, when comparing SCC with 0.5% and 1% recycled steel fiber content to control SCC samples (without steel fibers), the compressive strength of SCC increased by 5.04% and 7.56% respectively, the tensile strength increased by 2.99% and 5.97% respectively, plastic shrinkage decreased by 27.34% and 30.47% respectively, and 28-day drying shrinkage decreased by 3.2% and 4.6% respectively. Using recycled steel fibers combined with high-volume fly ash is a reasonable solution to save production costs and be environmentally friendly. Additionally, this solution not only improves the compressive and tensile strength but also limits plastic and drying shrinkage deformations of SCC. As a result, the durability of SCC is enhanced.
 
 

The effect of using treated domestic wastewater with different pHs on workability, mechanical, and durability properties of self-compacting concrete.

In the present work, we used treated domestic wastewater with different pHs in self-compacting concrete (SCC) to find the effect of treated wastewater with different pHs on the workability, mechanical, and durability properties of SCC. Eight different SCC mixtures were designed, including two control samples using tap water with a water-to-cement ratio (W/C) of 0.5 with 400 kg/m3 of cement and W/C of 0.36 with 440 kg/m3 of cement. Six SCC samples with the same characteristics as control samples except using treated domestic treated wastewater with different pHs. The results indicate that the workability of the SCC sample using the treated domestic wastewater in acidic pH was higher than the alkalinity state. Using treated domestic wastewater instead of tap water in SCC samples decreased compressive, flexural strength, and fracture toughness by less than 10%. Also, carbonation, 30-min water adsorption, and capillary water adsorption of SCC samples increased when treated domestic wastewater was used. The compressive strength of SCC samples made with treated domestic wastewater in an acidic state is less than about 5% in an alkaline state. The energy dispersive spectroscopy and the scanning electron microscope images confirmed that using treated wastewater instead of tap water, in SCC samples, reduced compressive strength because the Ca/Si ratio increased when treated domestic wastewater was used. The SCC samples with treated domestic wastewater in the alkaline state have a lower Ca/Si ratio. The higher compressive strength belongs to concrete samples that used treated domestic wastewater in an alkaline environment with a lower Ca/Si ratio.

A Comprehensive Investigation of Performance Characteristics, Mechanical Properties and Durability Parameters of Self-compacting Concrete Containing Iron Slag as Coarse Aggregate

In this paper, iron slag is used as partial coarse aggregate substitution in Self-compacting concrete (SCC). The SCC samples tests were conducted after 28 days of water curing for samples with 0%, 10%, 20%, 30%, 40%, 50%, and 60% iron slag as coarse aggregate substitutes. This paper evaluates slump flow, V-funnel, L-box, compressive strength, flexural strength, splitting tensile strength, surface water absorption, capillary water absorption, electrical resistance, acid resistance, and ultrasonic pulse velocity (UPV) of concrete samples. Furthermore, scanning electron microscopy (SEM) of samples was investigated for evaluating cement paste microstructure. Samples containing 20%, 60%, and 60% iron slag as coarse aggregate substitute have higher compressive, flexural, and splitting tensile strength than control samples (about 18.4%, 28.6%, and 16.9% higher, respectively). In addition, using 10%, 20%, 30%, and 40% iron slag as coarse aggregate increased the compressive strength. Moreover, incorporating iron slag as a coarse aggregate decreased the mass loss of samples which were exposed to the acid environment compared to control specimens. Using iron slag as partial coarse aggregate substitution reduced the porosity of the cement matrix compared to control samples (based on SEM images).

Evaluating resistance of ceramic waste tile self-compacting concrete to sulphuric acid attack

Ceramic waste tile aggregates produced from mixed coloured tile were utilized in self-compacting concrete (SCC). This research was aimed at assessing the performance of SCC in sulphuric acid environment by introducing ceramic waste tile (CWT) as natural fine aggregate replacement in different ratios (0%, 20%, 40%, 60%, 80% and 100%). SCC samples were exposed to a 3% sulphuric acid solution for 7, 28, 90 and 180 days. The transformation of mass, compressive strength, and micro-structure were used to assess the performance of concrete. It was discovered that CWT was sacrificial in nature when the SCC samples were subjected to an acidic environment, which helped to prevent damage to the cement hydration components that provided the strength. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) showed that the presence of CWT led to substantially less damage to the hydration products. Furthermore, the increment in replacement level after 60% has shown an increment of void ratio, leading to reduction in preliminary mechanical characteristics. It was concluded that 60% replacement level may provide the highest optimum performance in terms of compressive strength and sulphuric acid resistance. According to economic and ecological studies, SCC mixtures that comprise CWT are economical and have lower embodied energy and lesser CO2 emissions.

An experimental investigation of M30 grade self compacting concrete using mineral admixtures

Self-compacting concrete (SCC) is commonly used to create high-performance concrete since it does not require vibration to achieve a compacted state. The absence of standardized mix design and testing methods has hampered SCC's implementation. Since no vibration is required and noise pollution is reduced, it is gaining widespread acceptance. In construction, we have found a way to make every step of the process both less dangerous and more fruitful. This study aimed to produce a mix design for M30 grade SCC by the criteria established by EFNARC 2002. The SCC is made by substituting fly ash (FA) and metakaolin (MK) at percentages of 0%, 7.5%, 15%, 22.5%, and 30% of the cement volume and then adding 1.5 percent of superplasticizer to the resulting cement volume. According to EFNARC, the M30 grade SCC mix produced passed all of the tests above: the L-box test, the slump flow test, the V-funnel test, and the J-ring test. Additionally, compressive, tensile, and flexural strengths of 7- and 28-day-old SCC samples were tested, with results indicating that a 0%-30% substitute of MK and FA can be considered a suitable replacement and mix designs for M30 grade of metakaolin and fly ash-based self-compacting concrete have been proposed.

Effects of microsilica and polypropylene fibers on the rheological properties, mechanical parameters and durability characteristics of green self-compacting concrete containing ceramic wastes

In the developing countries, since a major part of the urban wastes is related to the construction sector, this study has used ceramic waste (CW) as a partial substitute for natural coarse aggregates to produce self-compacting concrete (SCC), and since the latter should have enough strength and durability, effort has been made to not only examine its rheological properties and mechanical parameters, but also study the effects of microsilica (M) and polypropylene fibers (PP fibers) on its durability characteristics (electrical resistivity, ultrasonic pulse speed and volumetric and capillary water absorption). According to the results, increasing the percent CW decreases the SCC efficiency, and increasing M and PP fibers increases its viscosity and, hence, decreases its flowability and passability, but increases its resistance against segregation. In this research, CW50M10P0.15 had the highest compressive strength – an increase of about 21% compared to the control sample – and CW25M5P0.3 showed the highest tensile and flexural strengths compared to the control sample. Adding CW reduced the durability of the SCC samples slightly, but adding M and PP fibers increased it. In the electrical resistivity test, CW25M10P0.3 showed an increase of about 168% compared to the control sample. Analyzing the scanning electron microscope (SEM) images revealed that mix designs containing ceramic wastes had a stronger ITZ, and adding M made the samples denser and more coherent.

Evaluation of the effect of silica fume on the fresh, mechanical and durability properties of self-compacting concrete produced by using waste rubber as fine aggregate

The supply of sand, which is obtained by disposing of natural resources for the purpose of concrete production and in accordance with production standards, is increasing rapidly and therefore its amount is rapidly depleted. A study is presented that aims to reduce the aggregate content by using this waste tire aggregate (WTA) in the construction industry, and thus, a sustainable production and conservation of nature is the basis. The water/binder ratio used in the study is kept constant as 0.39 and the binder dosage as 550 kg/m3. WTA and SF are replaced with sand and cement at the ratios of 5%, 10% and 15% by volume, and 5% and %15 b y weight, respectively. The fresh (slump flow, V-funnel, and L-box) and hardened (axial compression, splitting tensile strength, flexural tensile strength, diagonal tensile strength, and modulus of elasticity, chlorine penetration and sorptivity) properties of self-compacting concrete (SCC) mixtures produced in this way are evaluated. For the mechanical and durability tests, a total of approximately 500 SCC (100 × 100 × 500 mm: prism, 100 × 100 × 100 mm: cube and 100 × 200 mm: cylindrical) samples are produced. The mechanical experiments of SCC were carried out at 28-, 56- and 90-days age. The test results have shown that WTA substitute concrete, which can be used in terms of civil engineering in terms of all these features, has shown that it has sufficient performance.

Prediction of strength and analysis in self-compacting concrete using machine learning based regression techniques

Self-Compacting Concrete (SCC) has congested structural components and an inaccessible position. Mixing concrete multiple times becomes time-consuming and expensive. Due to a lack of competence in mixture design, analyzing appropriate mixture components and their influence on SCC's mechanical behavior might be a real-time concern in the construction sector. The work intends to create machine learning-based regression models to predict SCC compressive strength. A laboratory set of data comprising 99 SCC samples was used for this purpose. SCC's machine-learning regression model has many input and output parameters. Python machine learning was used to compare actual strengths. Linear regression, Lasso regression, Ridge regression, multi-layer perceptron regression, decision tree regression, and random forest regression are machine learning prediction methods. RMSE, MSE, MAE, and R2 measure model accuracy. The Random Forest model can efficiently estimate self-compressing concrete compression strength, according to the results. The RF model forecasts concrete's compressive strength accurately.

Compressive Strength Prediction of Self-Compacting Concrete-A Bat Optimization Algorithm Based ANNs

This article examines the feasibility of using bat-trained artificial neural networks (ANNs) to predict the compressive strength of self-compacting concrete (SCC). The nonlinear behavior of SCC challenges traditional modeling techniques. Therefore, this work takes advantage of the superior predictive performance of ANNs coupled with the bat algorithm. A database of 205 SCC samples collected from the literature is used to develop the ANN model. The correctness of the bat-based neural network model is then substantiated by contrasting its performance with that of the particle swarm optimization and teaching-learning-based optimization algorithms employed to train a neural network model. The statistical indices indicate the superior performance of the bat-based ANN model. In addition, a sensitivity analysis was carried out to determine the effects of various input parameters on the compressive strength of SCC.

Investigation on mechanical behaviors of Self-compacting concrete containing reclaimed asphalt pavement

In order to investigate the effect on mechanical properties of self-compacting concrete (SCC) with reclaimed asphalt pavement (RAP), SCC samples with RAP content of 0%, 30%, 60%, 90%, and 100% by weight were prepared. The stress–strain relationship and crack propagation mechanisms were researched by the uniaxial compression test and digital speckle correlation technique. Furthermore, a compression damage constitutive model was established. The results show that RAP has an apparent negative influence on workability and compressive strength of SCC with RAP content ranging from 0% to 100%. Peak stress and elastic modulus of SCC samples decrease with RAP content increase while peak strain of samples increases. The cracks number of the specimens increases significantly and energy absorption ability is improved with RAP content increase. The proposed damage constitutive model effectively describes the strain–stress characteristics of self-compacting concrete with different RAP contents and the results agreed well with experimental tests. The change rate of damage variable constantly decreases with RAP content increase.

Combined Effects of Metakaolin and Hybrid Fibers on Self-Compacting Concrete.

There is a need to develop new construction materials with improved mechanical performance and durability that are low-priced and have environmental benefits at the same time. This paper focuses on the rheological, mechanical, morphological, and durability properties of synthetic and steel fiber reinforced self-compacting concrete (SCC) containing 5–15% metakaolin (M) by mass as a green replacement for Portland cement. Testing of the fresh mixes included a slump-flow test, density, and porosity tests. Mechanical properties were determined through compression and flexural strength. A rapid chloride penetrability test (RCPT) and the chloride migration coefficient were used to assess the durability of the samples. A scanning electron microscope (SEM) with energy dispersion spectrometry (EDS) was used to study the concrete microstructure and the interfacial transition zone (ITZ). The results show that a combination of metakaolin and hybrid fibers has a negative effect on the flowability of SCC. In contrast, the inclusion of M and hybrid fibers has a positive effect on the compressive and flexural strength of SCC. The fracture of SCC samples without fibers was brittle and sudden, unlike the fiber-reinforced SCC samples, which could still transfer a considerable load with increasing crack mouth opening deflection. Overall, the chloride migration coefficients were reduced by up to 71% compared to the control mix. The chloride reduction is consistent with the resulting compact concrete microstructure, which exhibits a strong bond between fibers and the concrete matrix.

ELECTRICAL RESISTANCE OF HYBRID STEEL FIBER REINFORCED SELF- COMPACTING CONCRETE

Beton yüksek basınç dayanımı yanı sıra çok düşük elektriksel iletkenliği sahiptir. Bu çalışmada kendiliğinden yerleşen betonun (KYB) elektriksel özdirenci, iletkenliği ve sıcaklık artışı üzerinde uzun ve kısa çelik liflerin etkisini, lif kombinasyonu (tek ve karma) ve kısa çelik liflerin boyuna (6 ve 13 mm) bağlı olarak belirlemek için dört adet karışım tasarlanmıştır. Bu karışımlar, lifsiz referans, sadece uzun tek lif takviyeli ve uzun lif ile iki farklı boya sahip kısa çelik lif içeren iki adet karma çelik lif takviyeli karışım olmak üzere dört farklı karışım tasarlanmıştır. Tüm çelik lif takviyeli KYB karışımları hacimce toplam %1 lif içermektedir. Karışımların belirlenmesinde EFNARC tarafından önerilen işlenebilirlik testleri (Çökme-yayılma, t500 ve J-halkası yükseklik farkı) dikkate alınmıştır. Karışımlara ait mekanik özellikler (basınç, yarmada çekme ve eğilme dayanımı) ile elektriksel özdirencin belirlenmesi için numuneler üretilmiş ve toplam 90 gün boyunca 23±2 0C’de su içerisinde kür edilmiştir. Sonuçta çelik lif takviyesinin betonun elektriksel özdirencini düşürdüğü ve dolayısıyla iletkenliğini artırdığı tespit edilmiştir. Bunun yanında karma lifli KYB numunelerinin en düşük elektriksel özdirenç ve en yüksek iletkenlik ile sıcaklık artışına sahip olduğu görülürken, narinliği yüksek olan 13 mm boyunda mikro çelik lifin betonun elektriksel özellikleri üzerinde 6 mm boyunda mikro çelik life göre daha olumlu etkiye sahip olduğu bulunmuştur.

Study of shear‐thickening and shear‐thinning behavior in rheology of self‐compacting concrete with micro‐nano bubble

AbstractThis research investigated the effect of using micro‐nano bubbles and superplasticizers on the rheology of self‐compacting concrete (SCC). Eight mix designs were made with different values of 4–5.5 kg/m3 of superplasticizer. For comparison, half of the mix designs were made with micro‐nano bubbles, and the rest were made with tap water. Flowability, passing ability, and rheological tests were performed on all mixed designs. The results show that an increased rate of superplasticizer from 4 to 5 kg/m3 improved flowability and passing ability in all specimens. The yield stress and plastic viscosity of SCC reduction were higher in samples made with micro‐nano bubbles. The shear‐thickening behavior was observed in SCC samples produced with tap water and the superplasticizer, and the c/μ (positive) ratio increased. While in SCC with micro‐nano bubbles, the shear‐thinning behavior was observed, and the c/μ (negative) ratio increased with increasing the superplasticizer dose.

An appraisal of the models for the prediction of compressive strength of thermally damaged self-compacting concrete

Self-compacting concrete (SCC) mixtures were prepared using 5% and 10% micro silica (MS). Fresh properties are measured using slump flow with T500 time, L-box ratio and V-funnel time. SCC with lower MS content yielded better workability properties. Hardened SCC samples were heated up to 200 °C, 400 °C and 600 °C in an electric furnace and allowed to cool naturally. The compressive strength of unheated and heated samples after cooling was determined. It was observed that up to 400 °C, SCC with 10% MS suffered higher strength loss than SCC with 5% MS. For 600 °C, strength loss for both the SCC mixtures was approximately equal. Furthermore, residual compressive strength of one hundred seven SCC specimens (including eighteen of this study) was predicted using the residual compressive strength models available in the literature. Though the available models were proposed for normal vibrated concrete (NVC), statistical analysis showed that they could also be used for SCC.

Mechanical Properties of Silica Fume Modified High-Volume Fly Ash Rubberized Self-Compacting Concrete

The existing form of self-compacting concrete (SCC) comprises of a large amount of powdered and fine materials. In this study, a part of the cementitious material was replaced with constant high-volume fly ash, and a portion of fine aggregates was substituted by crumb rubber (CR). Besides that, silica fume (SF) was added, with the hope that by implementing a new type of nanomaterial, the loss in mechanical strength due to previous modifications such as rubberization and replacement will be prevented. Two variables were found to influence the constituent/component in the mix design: SF and CR. The proportion of SF varies from 0% to 10%, while that of CR from 0% to 30% by volume of the total river sand, where 55% of cement was replaced by the fly ash. A total of 13 rubberized SCC samples with CR and SF as controlling variables were made, and their design mix was produced by a Design of Experiment (DOE) under the Response Surface Methodology (RSM). The results reveal a slight increase in the mechanical properties with the addition of SF. The theoretical mathematical models and equation for each different mechanical strength were also developed after incorporating the experimental results into the software.

Structural performance of corroded reinforced concrete beams made with fiber-reinforced self-compacting concrete

The structural performance of corroded beams made with fiber-reinforced self-compacting concrete (SCC) was evaluated in this study. SCC samples reinforced with glass chopped fibers (GF) and polypropylene fibers (PF) without steel reinforcement were first made and assessed in terms of fresh properties, compressive strength, and flexural strength. Cylindrical SCC samples were then subjected to accelerated corrosion in order to determine the influence of SCC mixtures on the steel reinforcement corrosion in terms of the mass loss. Deep beams with a dimension of 700 mm × 100 mm × 300 mm were then made with selected mixtures and subjected to accelerated corrosion before evaluating the structural performance. Findings from this study showed that fiber-reinforced SCC can be utilized in the production of reinforced concrete without any detrimental effects on fresh and mechanical properties. The incorporation of GF and PF at a dosage of 0.06% and 0.1%, respectively enhanced the 90 days compressive strength and flexural strength by 15.4% and 40.8% compared to reinforced concrete made with plain SCC. Results from this study also showed that the use of fiber-reinforced SCC enhanced the structural performance of corroded beams in terms of flexural load capacity, stiffness, ductility and ultimate energy.

Influence of waste alumina powder on self-compacting concrete resistance under elevated temperature

Influence of Nano-Alumina (NA) powder prepared from damaged alumina rollers that are waste objects from the production line in a tile and ceramic factory on Self-Compacting Concrete (SCC) under elevated temperature are investigated in this study. Three mix designs including without NA, with 1%NA, and 2%NA, that were replaced for cement, were investigated under temperatures of 27 ̊C, 100 ̊C, 200 ̊C, 300 ̊C, 450 ̊C, and 600 ̊C. To evaluate compressive strength and modulus of elasticity (E-value) of each mix design, 7-day and 28-day samples were tested before or after heating for ten or 60 min. For each mix design, cured samples experiencing only the ambient temperature of about 27 ̊C were also tested as reference samples. Results show that using NA decreases compressive strength of 7-day samples in the ambient temperature, but improves their compressive strength after 10 min heating under the target temperature of up to 200 ̊C. Nano-alumina improves compressive strength of 28-day SCC samples by its pozzolanic activity for the ambient temperature and under 100 ̊C. For the higher target temperatures at both ages, NA particles are effective to reduce strength degradation due to heating. Compared to the samples without NA, compressive strength of the 28-day samples with 1%NA and 2%NA, after experience of 10 min heating, were 11.7% and 16.2% higher, respectively. These values for the samples experiencing 60 min heating were 22.4% and 26.5%. Results of E-value tests on 28-day samples exhibit positive influence of NA under ambient temperature and these nanoparticles are able to slow down degradation of E-value after an experience of ten or 60 min under the target temperatures. However, almost different from previous literature, the 2%NA has a higher influence to reduce SCC strength degradation than 1%NA. This may be attributed to the NA resource that is from waste materials containing some impurities.

Predicting the compressive strength of self‐compacting concrete containing Class F fly ash using metaheuristic radial basis function neural network

AbstractThe use of Class F fly ash (CFFA) as a partial replacement of cement in the concrete mixture can provide a wide variety benefits such as improving the mechanical properties, reducing the construction costs, and enhancing the environmental conditions. Compressive strength as one of the most critical mechanical parameters used in many design codes can be obtained either through costly and time‐consuming experiments or non‐destructive methods such as predictive models. In this study, a hybrid model of the radial basis function neural network (RBFNN) and firefly optimization algorithm (FOA) (RBFNN + FOA) was proposed for the prediction of the compressive strength of self‐compacting concrete (SCC) containing CFFA. For this purpose, a multi‐laboratory dataset containing 327 SCC samples made with CFFA was employed. The input parameters in the proposed models included the age of the specimen and the amounts of cement, water, CFFA, coarse aggregate, fine aggregate, and superplasticizer, and the only output parameter was the compressive strength of SCC. For comparison purpose, the artificial neural network (ANN) was also used to model the compressive strength of SCC containing CFFA. The results show that the compressive strength estimated by the proposed and ANN models have good accuracies compared to the experimental results. Moreover, several performance metrics showed that the accuracy of the proposed model is higher than that of the model developed based on ANN algorithm.

Effect of moisture content on tunnel fire resistance of self-compacting concrete coated with aerogel mortar

Self-compacting concrete (SCC) is widely used in tunnel linings that are subject to fire risks. During tunnel fires, personnel and structural safety are commonly threatened by the explosive spalling of SCC due to its high strength and high moisture content. Recent studies have suggested that a coating of fire-resistant material can efficiently prevent SCC from spalling during a tunnel fire. In this study, SCC samples coated with a 6 mm thick layer of silicon dioxide aerogel-cement mortar (SiO2-ACM) were prepared and compared with uncoated samples. The effects of different moisture contents (0%, 25%, 50%, 75% and 100%) on the fire resistance of SCC were investigated. The results show that SiO2-ACM exhibited excellent mechanical and durability performances as well as low thermal conductivity. During exposure to mimetic tunnel fire, the degree of spalling of SCC increased as moisture content increased. The SCC samples with the SiO2-ACM coating exhibited much less spalling than those without such coating. After the mimetic tunnel fire, the uncoated SCC samples had almost completely failed in terms of compressive strength, whereas the residual compressive strength of the coated SCC samples was more than 68·6% even for the SCC with 100% moisture content. Therefore, a SiO2-ACM coating provides an attractive means by which to enhance the behaviour of SCC during a tunnel fire.