Total Fracture Energy Research Articles

Effects of NaOH solution concentration and aging on fracture properties and ductility of ambient-cured heavyweight geopolymer concrete

In this paper, effects of NaOH solution concentration (i.e. 2, 4, and 6 M) and aging (i.e. 3, 7, and 28 days) on fracture properties and ductility behaviour of ambient-cured heavyweight geopolymer concrete (ACHWGC) have been investigated. Fracture parameters of the ACHWGC including total fracture energy (GF), initial fracture energy (Gf), fracture toughness (KIC), characteristic length (Lch), effective size of the process zone (Cf), critical effective crack-tip-opening displacement (δc) and the brittleness number (β) were determined using work of fracture method (WFM) and size effect method (SIZEM) and the results obtained were analysed. The results indicate that: (a) maximum fracture energy and the highest brittleness are achieved for samples with 4 M NaOH concentration. (b) as the age increases, fracture energy and brittleness of the samples increase. (c) the mixes gain approximately 82.47% and 86.26% of their 28-day initial and total fracture energies in the first 3 days, respectively. (d) increase in the rate of fracture energy, and decrease in the rate of characteristic length with respect to the mix age for 4 M NaOH concentration are more than those for the 6 M one. (e) as both the total fracture energy (GF) and the initial fracture energy (Gf) increase by the age, the GF/Gf ratio decreases. (f) at the age of 28 days, the GF/Gf ratios for the specimens with 4 M and 6 M NaOH concentrations are equal to 3.16 and 3.32, respectively and (g) as the compressive strength increases, the fracture energy, the fracture toughness, and the brittleness of the ACHWGC are enhanced.

Effects of span-depth ratios on the energy release rate for three-point bending beams

The effects of span-depth ratios on the energy release rate for three-point bending beams were examined. Expressions for the energy release rate for three-point bending specimens with various span-depth ratios were developed using linear interpolation method. The double-G fracture parameters were calculated through tests of three-point bending beams with the same span (800 mm) but various depths (100 mm, 150 mm, 200 mm, 250 mm and 300 mm) and the findings in literature. Results indicate that (1) with increasing the span-depth ratio, an almost constant initial fracture energy release rate was obtained, and slight decrease tendency of the unstable energy release rate was observed; (2) The empirical relationship between the initial fracture energy and total fracture energy suggested in size effect model was conformed using the unstable fracture energy release rate which was the same as the initial fracture energy; (3) Equivalence between double-G and double-K fracture model was verified; (4) Moreover, the analytical results of unstable fracture energy release rate exhibited a good consistency with the experimental ones, which were insensitive to the softening function.

Stubble resistance of rubber vulcanizates: Influence of short fiber and resin

Stubble resistance of tread rubber vulcanizate of a tyre is crucial, especially for the off-the road (OTR) tyres. However, it has not been vividly discussed in the literature. Here, we developed a test method for stubble resistance, and studied the effect of short aramid fibre and two different types of resins on the stubble resistance of a conventional tire tread recipe with a view to its improvement. Resin filled compositions, being flexible, showed better cut initiation resistance, as compared to aramid fibre filled stiffer compositions, by dissipating the stress through chain orientation. During penetration, both cut growth and frictional force were important. For the aramid fibre composition, the frictional force dominated, whereas the cut growth was predominant for the resin filled vulcanizates. How the different energies associated with the fracture, e.g. cut initiation and growth energies, frictional energy and total fracture energy, altered with respect to the modulus or elongation at break of the rubber vulcanizates has also been discussed. At 4–6 phr of aramid filler concentration, stubble resistance drastically improved. On the other hand, the resin at 4 phr concentration exhibited an overall improvement in stubble resistance as compared to the conventional recipe. In summary, the present work contributed to the effect of different parameters on the stubble resistance of a tire tread rubber vulcanizate using an inhouse developed new test method.

Bioinspired cementitious-polymer composite for increased energy absorption

Preliminary results are presented on the energy absorbing characteristics of a cementitious-polymer architecture bioinspired by the organic-inorganic composite structure of nacre. The proposed bioinspired architecture consists of an open cell, platelet-shaped 3D-printed thermoplastic lattice filled with high performance cementitious paste. The hypothesis is that, similar to nacre, the platelet arrangement and differences in mechanical properties of the thermoplastic lattice and cementitious platelets would result in increased energy absorption. Initial laboratory scale investigations were performed using notched beam samples subjected to static three-point bending. Stereo-digital image correlation was used to track global strain displacement field and Hillerborg’s method was used to estimate the total fracture energy. The results indicate that this “brick-and-mortar” hierarchy can increase the energy absorbing capacity of the composite by upwards of 2490% compared with the benchmark cementitious specimen. The load-deformation behaviour and total fracture energy of the bioinspired composite were found to be influenced by the platelet arrangement and size and the lattice thickness.

Effect of aging and moisture damage on the cracking resistance of rubberized asphalt mixture

Abstract The use of crumb rubber to modify asphalt mixtures has astounding economic and environmental benefits. However, the use of asphalt mixture modified by crumb rubber is uncertain specifically when it is added by the dry method due to the low stability and cracking performance of the produced mixtures. Moreover, the high air void content of the produced mixture results in its low resistance to moisture damage and aging effect. This study attempts to investigate the effect of moisture damage and aging on the cracking performance of rubberized asphalt mixtures. Indirect tensile strength test was used to investigate the CT index, fracture energy, and tensile strength. The IDEAL-CT characterization correlated well with field performance in terms of thermal cracking and reflective cracking. The test was conducted before and after exposure of the asphalt samples to two levels of aging and one level of moisture damage. Results show that the total fracture energy of rubberized asphalt is higher than that of the control mixtures. However, the rubberized mixture shows low tensile strength particularly for the moisture conditioning. Meanwhile, the rubberized mixture has a higher CT index value than the control mixtures.

Fracture energy comparison of aluminum and boron composites for fuel cell end plates

Fuel cells have become an attractive choice because they do not cause environmental and noise pollution. Additionally, they do not contain any moving parts and have higher efficiency than fossil fuels. Therefore, improving the capability of fuel cells helps to provide clean energy. Among fuel cells, the proton exchange membrane fuel cell (PEMFC) includes five main parts that are end plate, membrane, gas diffusion layer (GDL), catalyst layer (CL), bipolar flow plate (BFP). End plates hold PEMFC parts together securely. They should have high mechanical strength and low density properties. Therefore, the choice of materials for the PEMFC endplate is important. The calculated values of fracture energy show quantitatively how much energy must be placed in the sample to create the fracture surface. In this study, a finite element study was performed to understand the fracture behavior of cracks in the selected materials under different loading angles. The results revealed that the total fracture energy of aluminum was higher than boron-aluminum 50 and boron-aluminum 65 composites.

Relationship of rockburst and energy dissipation characteristics of brittle rock at great depth

Rockburst is defined as a major geological disaster of hard rock mass. At present, rockburst analysis mostly focuses on its mechanism, prediction, and preventive measures, and great progress has been made. However, a few comprehensive analyses on the rockburst mechanism still need to be investigated from different energy perspectives. From the energy perspective, this study analyzes the relationship between a rockburst and the destructive properties of T2b marble in the deep buried tunnel of the Jinping Secondary Hydropower Station. Our analysis includes strain energy accumulation and dissipation, shear fracture, energy release, and acoustic emission (AE). The obtained results show that in the energy release and dissipation processes, three dilatancy mechanisms trigger a rockburst, namely the tensile fracture extension control mechanism, closed fracture friction control mechanism, and their mutual transformation compound control mechanisms. Different mechanisms lead to different energy mutation patterns that determine the rockburst extent and scale. We also found that the strain energy of brittle rocks linearly increases with the increase of the confining pressure during the failure of the brittle rocks. The energy storage rate of the front peak at the lower confining pressure was significantly greater than that of the back peak. However, the difference gradually decreases as the confining pressure increases. The total shear fracture energy with the increase of the confining pressure first increases and then decreases. The peak before the shear fracture energy nonlinearly increases gradually, and the two fractures can be similar until the brittle–ductile transition. Lastly, the AE experiment shows that during the addition and unloading of brittle rocks at a great depth, three types of energy active periods and three types of energy decay periods are observed. The precursor to an instantaneous rockburst is the second type of energy fading period, while that to a delayed rockburst is the third type of energy fading period. The second type of energetically active period refers to the birth of a rockburst. The third type refers to the occurrence of a standard rockburst or a recurrence, such as a discontinuous rockburst.

The Effect of the Type and Amount of Synthetic Fibers on the Effectiveness of Dispersed Reinforcement in Soil-Cements.

The paper deals with mechanical properties of soil-cement composites made with non-cohesive soil and reinforced with dispersed fibers. The research was carried out on the basis of three soil-cement matrices whose compositions varied in terms of the volumetric fraction of cement paste and the water-cement ratio. Two types of polypropylene fibers were used as dispersed reinforcement: single fibrillated-tapes polypropylene fibers (SFPF) and bundles of coiled fibrillated-tapes polypropylene fibers (BCFPF). The fibers varied in terms of their length and mass fraction. The objective of the study was to assess the effect of the addition of fibers to soil-cement composites on their flexural tensile strength and on their behavior in the post-critical state. The studies were carried out after 28 days of curing. Bending tests were carried out to determine post-critical stress values σCMODi, stress values at which the matrix is destroyed (limit of proportionality) σLOP, maximum stress values transferred by the fibers σMOR (modulus of rupture), and total fracture energy Gf,tot as well as compressive strength. The test results obtained, and their analysis, indicate the significant impact of the dispersed reinforcement used on the performance of such composites during bending.

The effect of water-to-cement ratio on the fracture behaviors and ductility of Roller Compacted Concrete Pavement ([formula omitted

Roller compacted concrete (RCC) is a zero-slump concrete that has been extensively used in road pavements. This concrete has been considered, due to its economic and environmental potentials, including reduced construction and maintenance costs and greater environmental compatibility. A unique feature of the Roller Compacted Concrete Pavement (RCCP) is its low water-to-concrete (WC) ratio. Hence, RCCP is sensitive to the water content, compared to conventional concrete. This paper conducts an experimental studies on the effect of different ratios of WC on the fracture parameters of RCCP. For this purpose, three-point bending tests were performed on 162 notched beams and mechanical properties tests (compressive strength (fc), tensile strength (ft) and modulus of elasticity (E)) were performed on 54 specimens with different WC ratios (0.3to0.55). For all mixtures, the fracture parameters were determined using three methods: work of fracture method (WFM), size effect method (SEM), and boundary effect method (BEM). The results indicate a significant effect of WC ratio on RCCP fracture parameters, specifically, by decreasing w/c ratio from 0.55to0.3 it was observed that; (A) The initial fracture energy (Gf) and the total fracture energy (GF) increase in all three methods as a power function on fc; (B) The fracture toughness (KIC) increases linearly in SEM and BEM methods; (C) The characteristic length (Lch) in WFM, the effective length of the fracture process zone (Cf) in SEM, and the reference crack length (ductility index) (a∞∗) in BEM are decreased. The results also show that there is a relationship between GF measured by WFM method, and the Gf measured by SEM and BEM methods (GF≅2.43Gf(SEM), GF≅2.61Gf(BEM)).

New reactive rigid-rod aminated aromatic polyamide for the simultaneous strengthening and toughening of epoxy resin and carbon fiber/epoxy composites

In recent years, nanomaterial reinforced composites have been extensively studied, however, research on molecular composites, i.e. composites reinforced by rigid-rod macromolecules of large aspect ratio and superior mechanical properties, is still rare. In this study, we report that when a new organosoluble rigid-rod aromatic polyamide, poly(p-aminophenylene terephthalamide) (NH2-PPTA), is used as a reinforcing agent of epoxy resin, it is dispersed in epoxy at molecular level at low contents but forms nanorod- or nanofiber-like aggregates in the matrices at higher contents, thereby transforming the molecular composite into a nanocomposite. The reactive amino side groups can not only improve the solubility of NH2-PPTA in epoxy but also participate in the curing reaction, which leads to the formation of covalent bonds between NH2-PPTA and the matrix. At a content as low as 0.7 wt%, NH2-PPTA remarkably improves the strength and toughness of epoxy resin with a tensile strength of 100.7 ± 5.3 MPa and tensile toughness of 2860 ± 316 kJ/m3, which are increased by ~74% and ~118%, respectively. The strengthening and toughening effects are comparable to those provided by graphene oxide, and are higher than by many other previously reported inorganic nanofillers. Moreover, NH2-PPTA also significantly improves the mechanical properties of carbon fiber (CF)/epoxy composites. Flexural strength, total fracture energy and interlayer shear strength are increased by ~9%, ~67% and~27%, respectively. This is the first report on the transition of molecular composite to nanocomposite and the effective strengthening and toughening of epoxy resin and CF reinforced composites by NH2-PPTA.

The effect of aggregate gradation on concrete fracture energy using the work of fracture method

The micro-cracks that commonly occur in concrete structures are a potential source of crack propagation which leads to the possibility of catastrophic failure. Concrete cracks that occur propagating mainly along the interface zone that significantly conditioned by aggregate characteristics. Aggregate characteristics as concrete fillers have a significant role as a strain energy release medium known as fracture energy. This research is using an experimental investigation about the fracture characteristics of concrete using different gradations with a maximum diameter of 25 mm and 20 mm. The experiment includes a compressive strength test and a fracture parameter test. Three-point bend test was selected based on RILEM recommendations to calculate fracture parameters. The result has shown that the aggregate gradations used in concrete mixtures should take into account the effect on compressive strength and total fracture energy. Uniform gradations with smaller maximum sizes have high compressive strength but low fracture energy.

Simulation of Crack Propagation in Some Self-Compacting Concrete Structures and Determination of Their Strength and Ductility Performances

A study on the crack propagation, strength and ductility performances of some self-compacting concrete (SCC) structures with and without steel fibers can be made through experiments. But testing is laborious. For large structure like dam, testing is impossible. Sometimes, there could be insufficient laboratory facilities. Under such circumstances, the non-linear analysis of concrete structures became a novel design tool. It employs the power of computer simulation using finite element method (FEM) based software to support the structural engineers. The ATENA software uses smeared crack approach and is based on the Bazant’s crack band theory. The experimental total fracture energies of both SCC and steel fiber reinforced SCC (Steel fibers of length 25mm@ 0.6% by volume of mix) beams of strength M50 determined by RILEM’s work of fracture method, corresponding material properties and tension softening behavior are used as input data in the software. The simulated load-deflection/CMOD curve could be used to access the strength and ductility performances of the structures. The strength is identified by peak load and ductility by extension of tail end of this curve beyond yield load. Hence, this paper presents an appropriate methodology to determine the performances by simulation. Ductility is the desired property required for structures during earthquake. This can be improved by increasing the main steel reinforcement, incorporate fiber reinforced plastic (FRP) and steel tubes to impart it. But this could be uneconomical. In such cases, it is to be investigated that ductility can be improved by incorporating steel fibers of appropriate aspect ratio and volume in the mix. The ductility ratio (μ) determined from the load-deflection/CMOD curves is further used to evaluate the response reduction factor(R) by an empirical formula as established in earlier investigation. The R used in base shear formula of IS 1893(Part-I)-2002 code considers the ductility property of the structures that are subjected to lateral base shear during earthquake. Thus this study is carried out to identify the usefulness of simulation technique which is a new and robust tool to assess these performances of the structures using ATENA software that avoid the tedious testing procedures. This study investigates the influence of steel fibers in SFRSCC structures to improve their strength and ductility performances compared to SCC structures.

Transverse and longitudinal flexural properties of unidirectional carbon fiber composites interleaved with hierarchical Aramid pulp micro/nano-fibers

Unidirectional carbon fiber reinforced polymer (UD-CFRP) composites designed for ultimate tensile strength and stiffness along the fiber direction are vulnerable in the transverse direction. In this study, UD-CFRPs were reinforced in the transverse direction using sparsely distributed hierarchical Aramid pulp (AP) micro/nano-fibers between 2 and 8 g per square meter (gsm) per ply interface. Those AP micro/nano-fibers, a few hundred microns in length, effectively formed an ultra-thin interleaving layer around 20 μm in thickness between carbon fiber plies. Flexural properties along and perpendicular to continuous carbon fiber direction were measured under three-point-bending (3-P-B) to determine the toughening effects of AP. Flexural loads in both longitudinal and transverse directions have been enhanced by 30% and over 100% respectively from those randomly distributed AP micro/nano-fibers with diameters varied from a few hundred nanometers to 10 μm. Even slight increase in the elastic modulus of AP-toughened CFRP along the fiber direction was observed. Total fracture energy absorption, initial cracking and final fracture loads were measured and compared, indicating AP micro/nano-fibers have contributed to the high strength, high toughness and high modulus characteristics of AP-interleaved UD-CFRPs. Details on toughening mechanisms were revealed from SEM and cross-section optical microscopy examinations. Comparisons of unreinforced UD-CFRP and AP-toughened UD-CFRP showed the hierarchical AP micro/nano-fibers indeed played an important role in composite microstructure design and property optimization. The ultra-thin interleaved AP veil around 20 μm in thickness can be conveniently incorporated into pre-preg fabrication so that the extra interleaving step can be eliminated, i.e. the toughened pre-pregs can be used as normal pre-pregs in the final composite forming.

Characteristics of the mechanical behavior of Ti–6Al–4V multilayer laminate under impact loading

Multilayer laminates comprising thirteen layers of Ti–6Al–4V alloy were produced by diffusion bonding. The influence of the processing conditions on the microstructure and mechanical properties of laminates were determined. The multilayer laminates were tested at room and liquid-nitrogen temperatures under impact bending tests with recording of dynamic loading diagrams. The influence of the interfaces pores on the total energy of fracture, the energy of crack initiation and the energy of crack propagation was analyzed. The impact strength value of the laminate decreased by 1.7 times for the crack divider orientation, and it increased by 14 times for the crack arrester orientation with the relative length of pores increasing from 1 to 30%.

Investigation of size effect and smeared crack models in ordinary and dam concrete fracture tests

This study aims to investigate the size effect and smeared crack models in concrete fracture tests, and explore whether such non-linear models can show the effects of size or not. In the present analysis, the fixed smeared crack model (FCM) was developed for cracked concrete specimens of laboratory size under three-point bending and wedge splitting, and the different fracture parameters of the size effect model were evaluated using the data obtained from the laboratory and numerical analysis. According to the analysis, the need for a separate examination of the effects of material properties of ordinary concrete and dam concrete was shown. Besides, even the creation of specific equations for them which was due to the effect of the fracture energy, the effective length of the fracture process zone (FPZ) and the fracture toughness was clearly demonstrated in the size effect and the related numerical equations. It is concluded that the fracture parameters obtained from Bažant’s size effect model and other nonlinear fracture models including the FCM are influenced by the specimen size. The results indicate the relative weakness and decay of this type of the FCM described in this study can be used to better describe the effects of the size, especially when the concepts of the initial and total fracture energy are not considered.

Direct tensile self-sensing and fracture energy of steel-fiber-reinforced concretes

Based on the experimental tests, the tensile self-sensing and fracture energy of steel-fiber-reinforced concretes (SFRCs) were focused to investigate. Firstly, the plain mortar matrix of SFRCs produced the strain-softening behavior and no self-sensing ability. Secondly, among six fiber types with same amount 1.5 vol.-% as follows: macro twisted (T30/0.3), macro smooth (S30/0.3), macro hooked (H30/0.375), meso twisted (T20/0.2), meso smooth (S19/0.2) and micro smooth (S13/0.2), the T20/0.2 revealed the highest first gauge factor (GFcc) and first-cracking strength whereas the S30/0.3 produced the highest first-cracking strain. Thirdly, the strain-sensing capacity of SFRCs using macro twisted fiber was observed to increase with increasing of fiber content in range of 0–2.0 vol.-%. Fourthly, in evaluating three SFRC matrices with same amount 1.5 vol.-% macro hooked fibers including M1 (control), M2 (added CB), M3 (added GGBS), M2 produced a significant enhancement in both self-sensing capacity and tensile strength while M3 produced a slight enhancement of them, in comparison with M1. Finally, the fracture energy of the investigated SFRCs were comparatively evaluated as follows: the ratio between elastic fracture energy and total fracture energy was the lowest, from 0.02 to 0.08 while the ratio between localized fracture energy and total fracture energy was the highest, from 0.38 to 0.82.

Wedge-Splitting Test on Carbon-Containing Refractories at High Temperatures

The mode I fracture behavior of ordinary refractory materials is usually tested with the wedge-splitting test. At elevated temperatures, the optical displacement measurement is difficult because of the convection in the furnace and possible reactions of refractory components with the ambient atmosphere. The present paper introduces a newly developed testing device, which is able to perform such experiments up to 1500 °C. For the testing of carbon-containing refractories a gas purging, for example, with argon, is possible. Laser speckle extensometers are applied for the displacement measurement. A carbon-containing magnesia refractory (MgO–C) was selected for a case study. Based on the results obtained from tests, fracture mechanical parameters such as the specific fracture energy and the nominal notch tensile strength were calculated. An inverse simulation procedure applying the finite element method yields tensile strength, the total specific fracture energy, and the strain-softening behavior. Additionally, the creep behavior was also considered for the evaluation.

Combined effects of steel fibers and water to cementitious materials ratio on the fracture behavior and brittleness of high strength concrete

This experimental program investigated the effect of steel fibers and water to cementitious materials ratio (w/c) on the fracture characteristic of plain high strength concrete (HSC) and high strength steel fiber reinforced concrete (HSSFRC). In this research, the w/c ratios of 0.24 and 0.35 as well as four volumetric steel fiber contents of 0.2%, 0.4%, 0.6%, and 1% were examined. Two methods including size effect method (SEM) and work of fracture method (WFM) were applied to determine the fracture properties of concrete. Based on the experimental results, by increasing the steel fibers and decreasing the w/c ratio in HSSFRC, the total fracture energy (GF), characteristic length of concrete (Lch), initial fracture energy (Gf) and fracture toughness (KIC) were increased. Also, for steel fiber content greater than 0.2%, the effective length of fracture process zone (Cf) was increased; however, the brittleness number (β) was reduced. The GF/Gf ratio from 2.53 and 2.5 in HSC was increased to 11.88 and 10.26 in HSSFRC when w/c ratio was increased from 0.24 to 0.35.

Fracture Parameters of Cement Mortar with Different Structural Dimensions Under the Direct Tension Test.

In this paper, we measured the fracture properties of cement mortar—which is composed of sand and has a nearly constant diameter—using a direct tension test. Four double-notched mortar bar specimens with different structural dimensions were assessed. The failure load, load-crack mouth opening displacement, and elongation of the gauge length were measured under direct displacement control. The fractured surfaces were scanned and measured so that we could calculate the tensile strength accurately and determine the fracture energy and characteristic length. The average ratio of total fracture energy (GF) to specific fracture energy (Gf) was 1.94; this was lower than the typical value for concrete, of 2.5. The direct tension test showed that the double-notched mortar specimens had a smaller fracture processing zone after the initiation of tensile cracks, so the tail portion of the softening branch was small. This decreased the GF/Gf ratio. We verified this result based on a nonlinear fracture mechanics simulation and found that it agreed well with our experimental results. We also investigated the size effects of four different scaled specimens while holding the ratio of structural dimension, d, and notch length, a is constant, so that there was no shape effect. The traditional linear elastic fracture mechanics (LEFM) prediction and Bažant’s size effect law yield a gradient closer to 1/2 in the case of relatively large specimens. In the case of our cement mortar specimens, this prediction was not supported, where the value of the slope was 1/0.727. This was unexpected because LEFM predicts strong size effects. One possible explanation for this result is that the size effects of concrete are most often evaluated using a bending test; also, concrete has a larger maximum aggregate size than mortar. Due to the random heterogeneities in aggregate distribution, higher tail energies may be seen for concrete, leading to differences in the GF/Gf ratio. At the same time, the peak tensile stress could be affected by the relationship between structural dimensions and aggregate size.

An experimental investigation on fracture parameters and brittleness of self-compacting lightweight concrete containing magnetic field treated water

In this study, an experimental research on the fracture parameters of self-compacting lightweight concrete (SCLC) using tap and magnetic water (MW) is presented. For all SCLC mixtures, common fracture parameters were specified by means of both work of fracture method (WFM) and the size effect method (SEM). Three-point bending tests were carried out on 90 notched beams with six mix compositions. The beams were made from mixes with three different water to cement (w/c) ratios of 0.37, 0.47 and 0.52; also, both tap and magnetic water were consumed in the concrete mixes, separately. The results of this research showed that by using MW in SCLC and decreasing w/c ratio from 0.52 to 0.37: (a) both initial fracture energy Gf and total fracture energy GF increased; (b) the fracture toughness and the mechanical properties of SCLC improved. Additionally, the achieved data exhibited that there was a reasonable relation between the total fracture energy obtained by WFM and the initial fracture energy achieved through SEM. The average of GF to Gf ratio in SCLC was 2.70. Furthermore, by using MW in SCLC mixtures, compressive strength, splitting tensile strength and modulus of elasticity increased up to 18%, 9% and 10%, respectively.