Effect of adsorption interactions of Arabic gum with cement

This study seeks to investigate the influence of cement and Arabic gum on the physico-mechanical and microstructural properties of cementitious composites. The influence of varying quantities of Arabic gum on the hydration, fluidity, mechanical performance and microstructure of cement paste was investigated. The influence of Arabic gum on slant shear performance and capillary water absorption was also investigated. The results indicate that the workability of cement was diminished as a result of the ability of Arabic gum to make the cement paste cohesive. It is evident that when the gum Arabic concentration increases from 147 to 174 mm, the resultant slump value for various w/b ratios drops. The adsorption characteristics showed that for a 15 mg g−1 dosage at 60, 45, 30, and 15 min, respectively, 1.43, 1.32, 1.25, and 1.03 mg g−1 are achieved. For 1% gum Arabic substitution, the highest flexural strength percentage growth is achieved at 38.46%, 23.74%, and 17.29% at 7, 14, and 28 days, respectively. In addition, the inclusion of Arabic gum improved the slant shear strength of cement composite, making it ideal for use as a building repair material with significant application potential. Experiments on the bonding behavior of the produced cementitious composite with the old mortar reveal that the shear bond strength was greatly increased, demonstrating the compatibility between the old and new cement composites. The microstructure and the porosity of the cement matrix also showed denser and compact matrix making them durable to attain better service life.


Introduction
Cementitious composites are a popular building material due to their superior durability, fire resistance, cost, and availability [1].Nevertheless, due to the weak flexural behavior and inherent flaw at the molecular level of CSH micro crystal formations, their use in many prospective applications remains limited [2].As the most used building material, concrete is strong, elastic, pliable, and workable [3].Traditional concrete uses lots of cement and natural aggregates, which wastes energy and causes environmental problems [4].As a result, many researchers have been developing novel approaches to incorporating a wide variety of industrial wastes into concrete, opening up a promising avenue for the potential use of wastes in the development of efficient concrete [5][6][7].Although the use of fly ash (FA) as a replacement for cement has a favourable impact on the structure and mechanical characteristics of concrete, it has a significant adverse effect on the functionality of concrete in the early phases of its curing process.With the goal of lessening the severity of these unfavourable consequences, the early acquisition of strength has been made possible by employing a chemical nanoadmixture that was developed specifically for this purpose.Throughout the first twelve hours of the curing process for composites, it is noted that the biggest rise in mechanical strength metrics as well as rapid growth of the essential matrix phases take place [8].The promotion of the geopolymerization process that leads to microstructural densification is achieved by incorporating SF into concrete in an amount that is sufficient but not excessive.On the other hand, an excessive amount of SF will react with the alkaline solution to produce hydrogen, which will result in the formation of a porous microstructure and, as a direct consequence, a reduction in strength [9].The pond ash had a significant silica content but only a small amount of calcium, which helped improve its long-term mechanical qualities such as compressive strength, splitting tensile strength, flexural strength, and impact strength.The durability performance of optimized green concrete was significantly improved by the inclusion of both pond ash and GGBS, which demonstrated a beneficial influence on the performance [10].Although the value of nanoparticles has long been understood, their use in cementitious materials is currently accelerating because they can be crucial in mitigating the negative impacts of cement's high SCM content.As a result of providing a nucleation site for hydration reactions, nanosilica (NS) added to Portland slag cement at an ideal amount of 1% led to an improvement in early-age strengths and setting times [11].Using tailored blended cements with nS and CFA content (up to 30% replacement level) can improve concrete composites and lower cement-based materials' carbon footprint, making them more eco-friendly.The synergistic and beneficial benefits of using CFA and nS together can be seen in the improved mechanical properties and microstructure of concrete [12].
Due to the outstanding compatibility with the hydrates of cement, organic polymers of various chemical origins and bases have been utilized to improve the flexural performance, toughness and flexibility of cementitious systems [13].Synthetic polymers such as SBR latex, epoxy, ethylene, acetates, acrylamides, and cellulose ethers are frequently used in cementitious composites [14][15][16][17].Bio-polymers such as Xanthium Gum , Guar Gum , and sodium alginate powders have also been successfully used to improve the durability and flexural performance of cementitious composites [18][19][20].The durability of any cementitious composite depends on the material's ductility in the face of approaching loads.It is demonstrated that polymer-modified cementitious composites (PMCC) exhibit superior performance and durability due to the synergistic effect of the best inorganic and organic properties of cement and polymer, respectively [21,22].In recent years, highly defect-free cement-based materials with a higher elastic modulus and flexural strength for use in structural applications have been developed after receiving considerable attention over the past few decades [23,24].Polymers in the form of re-dispersible powders and solutions can improve the mechanical behavior of composites by around 30%, while epoxy additives have improved the flexural performance of cementitious systems [25,26].Due to the excess or simultaneous usage of a mixture of polymers in cementitious systems had a negative effect due to the intertwining and aggregation of the polymers.The improvement in performance of cementitious composites is mostly attributable to an increase in the system's molecular mass, which results in stronger stress resistance properties [27].Due to the formation of agglomerates and micro cracks in the system, the majority of studies indicate that the performance of cementitious composites diminishes when the binder content exceeds 0.8% to 1% by weight [28,29].
The use of any polymer in a cement matrix necessitates a comprehensive understanding of the physical and chemical interactions between the polymer and cement, which is the present focus of many studies [30][31][32].The physical interaction of the polymer with the cement is primarily characterized by the formation of a polymeric layer on the cement grains, resulting in a sheathing effect, whereas the chemical interaction is characterized by the formation of cross-linked chains or networks in the cement, resulting in the formation of highly ordered microcrystalline structures [33,34].It was discovered that the carboxyl groups of polymers form strong bonds with the CH and CSH hydration products, which consist of well-spaced mesocrystals of CSH and polymeric layers [35,36].Several polymers have been studied, and numerous research works have been published on the use of synthetic and chemical-based polymers to induce polymerization in the cement matrix, resulting in the formation of long-oriented crystals of CSH and the development of sheets of calcium silicates to improve the interfacial strength and toughness of cementitious composites [37].However, very little research on the utilization of natural polymers of biological origin in cementitious systems has been published, and none has examined the mechanical and shear performances of such composites.
As of now, the research works connected to the use of polymers in cementitious systems are restricted to synthetic polymers, and there are no data on the mechanical, bond, and shear performance of natural polymers in cement.Therefore, this research aims to improve the flexural and shear performance of cementitious composites, as well as their longevity, through the incorporation of Gum Arabic polymer into the Ordinary Portland Cement system.The effect of the Gum Arabic polymer on the workability/bleeding, flexural, shear, and durability performance is evaluated, and the appropriate proportions of the Gum Arabic polymer are determined for improved cementitious composite qualities.This research demonstrates a novel application of Gum Arabic, a natural polymeric material, for the development of new cementitious composites with better flexural and shear performance and the needed endurance.

Materials and mix proportion
The primary binder is ordinary Portland cement (53 grade), which meets the Indian standard with a 28-day strength of 56 MPa and a density of 3122 kg m −3 .The cement had a fineness of 3.230 cm 2 /g and initial and final setting times of 125 and 190 min, respectively.Table 1 displays the chemical composition of cement employed in this study.The Gum Arabic employed in this investigation is a naturally occurring enzyme supplied commercially by Astrra Chemicals, Tamilnadu and its chemical characteristics are listed in table 2. Six batches of cementitious composite mixtures, including varied amounts of Gum Arabic (0 to 1.5%), were produced.The cement content was taken as 1563 kg m −3 and content of water is taken as 312 kg m −3 .The cement was mixed in a pan-style cementitious composite mixer, which allowed for a total mixing time of around 9-10 min.The calculated amounts of water were mixed with the measured Gum Arabic to form an aqueous solution.The ratio of water to binder was kept at 0.35.In the mixer, the dry cement was combined with the calculated half of the water content, which contained Gum Arabic, and stirred for 3-4 min at a constant speed of around 300 rpm.The remaining quantity of water is then added, and the mixture is continually stirred for approximately six minutes at a steady speed of 1,400 revolutions per minute.The cement mixtures were poured into the corresponding moulds and compressed on a vibrating table following mixing.The specimens in the mould were sealed and kept under laboratory conditions for approximately 24 h to prevent the escape of moisture, and then subjected to water curing until they were tested.

Experiments
The fluidity of the cement mixture was measured using a mini-slump cone test on a glass surface on a vibration table.Diverse w/b ratios and gum Arabic proportions were used to determine the spread values as a function of the flow value with ±1 mm precision.The test for bleeding was conducted according to the standard ASTM C940-22 technique.The new cement paste was added to a 1000-mL graduated cylinder after mixing for 2 min, until the sample's volume was 800 ml.To stop the bleeding water from evaporating, the cylinder was then put on a smooth, vibration-free surface and coated with a thin layer.To the nearest 1 ml, the sample volume, the reading time, and the values were all estimated.If there was any bleeding, it was checked in the graduate at intervals of 30 min for the first 120 min and then every hour until two consecutive readings revealed no more blood.The following equations (1) and (2) represents the bleeding and final bleeding calculations in fresh cement paste: Vb 100 1 where, V b , V t , V g , V b , V w denotes the sample volumes at beginning stage of test, specified time intervals at upper water surface, grout volume at prescribed time intervals on upper grout surface and decanted bleed water respectively.The adsorption of gum Arabic on cement and other powder materials was tested using the approach applied in previous studies.The adsorption quantities were determined experimentally using the volumetric method and UV-visible spectroscopy.Using a 250-mL volumetric flask, the volumetric method was carried out, and the amount of gum Arabic absorbed by the raw materials, both individually and in combination, at various time intervals was determined.The adsorption quantities are calculated using UV-visible spectroscopy.The internal relative humidity of the cement mortar was studied using a digital sensor which shows the relative humidity and temperature inside the cement mortar.The experiment was conducted on cement mortar cubes (150 mm size) and the variations in the relative humidity were measured at different time intervals.The experimental setup is shown in figure 1.The digital sensor measured the relative humidity and temperature to an accuracy of 1.5 RH and 0.5 °C respectively.As specified by ASTM C348-21 standard, the 28 days flexural strength of cement mixes were evaluated using specimens measuring 40 by 40 by 160-mm, respectively.Also their test findings were reported as the mean of three values.According to the method outlined in ASTM C882/C882M-20, slant shear tests are commonly used to assess the bond strength.According to ASTM standards, 0.5 mm of epoxy resin thickness was used.The cylindrical specimens for the slant test were sawed in half with a diagonal bonding region at a 30°angle from the vertical following the appropriate curing.Each specimen in this group was a cylinder with a 150-mm diameter and 300-mm height.The base mortar is comprised of cement and sand, whereas the overlay mortar contains Gum Arabic in addition to cement and sand.Circular discs measuring 100 mm in diameter and 50 mm thick were used for the sorptivity test, which was carried out in accordance with ASTM C1585's instructions.The cylinders were initially dried for around 24 h in an electric oven set at 100 °C.
The specimens were then chilled until they reached room temperature in preparation for the test.The water level was raised 5 mm above the bottom of the cylindrical specimens when they were submerged in it.High-bond polymers were used to seal the specimen's other sides, creating an impermeable surface.The formula below (equation ( 3)) was used to get the absorption coefficient after the capillary absorption of water was measured over various time intervals: where 'w' is the total weight of water absorbed, 'a' is the specimen's cross-sectional area, 'S' stands for sorptivity coefficient, and 't' is the duration of the specimen's interaction with water.The microstructural studies are carried out through FTIR and SEM-EDAX analysis.
The fragments of the specimens after subjected to strength tests were sealed in plastic bags to carry out the microscopic studies.The fragments were sized 3-4 cm after drying in oven at around 60 °C.The SEM images were obtained from SEM, ZEISS EVO device operating at secondary electron mode at an accelerating voltage of

Fluidity and bleeding
The fluidity of the cement mixtures decreased as the percentage of gum Arabic in the mixture increased, and the values were significantly reduced at the lower dosages, whereas at the higher dosages, a slight decrease in fluidity was observed, which is consistent with the results presented in the previous research conducted on the use of gum Arabic in cementitious composites [38,39].The rise in fluidity at lower Gum Arabic concentrations illustrates the particle-bridging capacity of the Gum Arabic with cement particles and other powder components, thus decreasing the fluidity of the mixes.The decreased fluidity of cement mixes with increasing concentrations of gum Arabic as evident from figure 2 suggests the better particle-bridging capability and, in particular, attraction, demonstrating the less hydrolysis action of gum Arabic in cements systems.
The cement bleeding test was conducted according to the technique described in ASTM C940.The bleeding quantities of water containing different mixes of Gum Arabic were tested and given as the mean of three separate trials.Figure 3 depicts the bleeding of the cement mixture with Gum Arabic at various time intervals up to two hours.The cement mixture with no gum Arabic bled the most, whereas the mixture containing 1.5 percent gum Arabic bled the least.In contrast to normal cement mixtures, gum Arabic compositions showed an increase in bleeding water as time passed.These results indicate that after a specific concentration of Gum Arabic, the hydration of the cementitious system is changed, resulting in a decrease in the amount of water consumed by the hydrating system.

Adsorption characterization
Using UV adsorption spectroscopy, the adsorption behavior of gum Arabic on cement particles was investigated.Gum Arabic is typically miscible with water and can produce a homogenous dispersion.The absorption phenomenon was studied using the UV absorption values at 220 nm when mixed with cement.The adsorption of gum Arabic molecules on cement grains was analyzed using pore solution analysis, and the results are displayed in figure 4. The pore solutions were extracted after 15 min, 30 min, 45 min and 1 h of mixing, and the results indicate that the gum Arabic molecules were absorbed more after 30 min, resulting in minimal interaction with the early hydration of cement.
Moreover, the amount of adsorption was significantly higher in cementitious composites containing 1% gum Arabic, but the adsorption slightly increased without much variation at greater amounts of gum Arabic in cement, showing that a lower dosage of gum Arabic is suitable for the adsorption of molecules on cementitious substances.At one hour, the pore solution contained free Gum Arabic molecules, with roughly fifty percent of the weight remaining following the addition of 1% Gum Arabic.To investigate the gum Arabic effect, the pore solution of the cementitious composite was extracted at various time intervals.After one hour, no further adsorption of gum Arabic molecules on the cement or initial hydration products is seen, showing that 0.5% is the ideal concentration for preventing the presence of free gum Arabic molecules in the pore solution of cementitious composite.The addition of gum Arabic, on the other hand, showed no discernible changes in adsorption values with time and concentration, while lower proportions of gum Arabic additions of 0.5% indicate that over 95% of the gum Arabic molecules are being adsorbed by the cementitious materials, indicating that the saturation point has not been reached.Gum Arabic is suitable for use in cement systems because of its time-dependent adsorption, which results in higher adsorption levels 15 min after mixing.

Relative humidity measurements
The cement sample relative humidity measurements were conducted in accordance with earlier studies [40].The experimental setup is depicted in figure 5(a) and plastic tubes of various dimensions were positioned at various depths on a prismatic specimen measuring 150 mm × 150 mm × 600 mm.The sensors were put within the tube, and the sensor's accuracy was 0.1%.(Relative humidity testing equipment).By sealing the remaining three sides, the drying of the cementitious composite was secured on one surface.Figure 5(b) displays the results of relative humidity measurements at various depths.The RH values of the cement at different depths grew as the depth increased, however the RH values dropped drastically in areas close the ambient exposure.As can be observed, the RH values at a given depth of the cement increased with increasing Gum Arabic additions, confirming the internal curative effect of the gum Arabic.With the addition of Gum Arabic, the rate of decline of relative humidity values decreased over time.As the Gum Arabic dry, they might release water into the cementitious composite that surrounds them.

Flexural strength
Figure 6 displays the flexural strength values of the cement mixtures at various ages.At 28 days, the use of Gum Arabic increased the flexural strength by approximately 17.3% and 14.5%, with 1% and 0.75% Gum Arabic inclusion respectively.Subjected to water curing, the strength values increased up to a particular proportion of Gum Arabic addition, after which the flexural strength decreased.Gum Arabic additions of up to 1% increased the flexural strength of cement and therefore, Gum Arabic in the range of 0.75%-1% can be utilized to densify the microstructure of cement.The decrease in flexural strength beyond a specific proportion of Gum Arabic may be attributable to the increased viscosity of the generated mixture, which traps air bubbles in cementitious composite during mixing, so causing voids.In addition, the disruption in the homogeneity of the cementitious composite was produced by the larger fraction of Gum Arabic in the cement matrix that resisted the uniform distribution of the cement particles.This increase in flexural strength attributable to Gum Arabic is explicable; however it is likely due to their exceptional binding capacity.In addition, no previous research on the effect of the Gum Arabic on the flexural performance of cement has been documented and hence cannot be compared with the previous results.The findings of the flexural strength test also reveal a critical method for enhancing the mechanical performance of cementitious composites.Therefore, the Gum Arabic has a considerable potential for enhancing the mechanical performance of cement with the correct dispersion of Gum Arabic at a lower concentration level in aqueous form.Due to the substitution of Gum Arabic for water, the water quantity is adjusted correspondingly, resulting in no noticeable changes to the fresh attributes of cement.The results also indicate that lesser quantities of Gum Arabic had no impact on the dispersion of fibres and tiny particles in the cementitious composite.

Slant shear strength
Figures 7 and 8 illustrates the influence of Gum Arabic on the bonding behavior of modified cement and traditional cement (old cementitious composite) as assessed by slant shear strength.The compressive strength of the base mortar, onto which the overlay is laid, remained consistent throughout the experiment at 20 MPa.As depicted in figure 7, the overlay mortar was laid on top of the base mortar with and without grooves.As the overlay mortar's flexural strength increased, the slant shear strength likewise increased.It can be demonstrated that the addition of gum Arabic increases the slant shear strength of cement, which can be related to the composite's higher cohesiveness.The surface roughness of the cement has a substantial effect on the adhesion of new cement to old cement.The enhanced tangential shear strength is only found up to 1.25% Gum Arabic content, after which the strength decreases.The improvement in slant shear strength of the cementitious composite as it ages is also plainly apparent.The increase in adhesion and slant shear strengths might also be attributed to the porosity of the structure.Reducing the porous surface structure of cement increases the surface area of contact between the old and new cementitious composite surfaces, hence enhancing shear strength.The enhanced slant shear strength of Gum Arabic modified cement mixes can also be attributed to the lower internal pore contents, decreased generation of air voids, decreased WC adoption, and increased bond surface area and bond strength.It is evident from the data that the slant shear strength of cementitious composites rose as the percentage of GA in cement increased.Comparing the slant shear values of grooved and plain base concrete revealed nearly identical values at a higher fraction of GA, suggesting the bond improvement of the new cementitious composite compared to the old cementitious composite, even without groves.The increased slant shear strength of the composite can be attributed to the larger cohesive force demonstrated by cementitious composites with fewer voids and more compacity.However, it can be observed that the slant shear strength values fall significantly as the GA proportion increases beyond 1.25 percent in composites without groves.This may be due to the air voids formed during the process of overlaying and hardening.

Capillary water absorption
Figure 9 displays the capillary water absorption values of cementitious composite after 24 h of immersion.The water absorption values of the cementitious composite decreased with increasing Gum Arabic fractions up to a maximum of 1.25%.The capillary water absorption values decreased over 47.2% at 1.25% Gum Arabic dosage  on comparing to reference mix, qualitatively giving an idea of the porosity values.The water absorption test is a measure of open porosity of the cementitious composite and it can be seen that the water absorption values of certain gum Arabic mixes with proportion greater than 1% were marginally higher than those of other mixes with but was significantly lower than the control cement paste.The cement samples with 1.25% gum Arabic displayed lowest water absorption values showing that the water-curing technique enhances the void content of cement in comparison to plain cementitious composite.However, only after 16 h, the cement mixes with more than 1% gum Arabic exhibited constant values indicating the instability of the cement mixes towards water absorption.Despite the fact that gum Arabic improved the water tightness of cement mixes at early ages, the acceleration of the hydration rate at a very young age may cause expansion at later ages, leading to swelling pressure and the formation of micro cracks, thereby increasing the water absorption values at older ages.Due to the continual hydration of cement and the growing duration covering up the initial cracks generated by higher gum Arabic proportions in cementitious composite, specimens subjected to capillary absorption testing demonstrated less water absorption with increasing duration as compared to plain cement paste.Thus, the use of Gum Arabic on cement water absorption clearly demonstrates reduced water absorption up to a specific dosage, beyond which water absorption increases for all durations.

Fourier transform infrared analysis
Figure 10 displays the FTIR spectra of cement mix using Arabic gum additions.The broad spectrum around 3500 cm −1 corresponds to the -OH groups (stretching vibrations) and 1600 cm −1 refers to bending vibrations.The -OH vibrations represent water molecules that have been absorbed by the cement surface or are trapped in its pores.As depicted in the picture, the -OH vibrations changed as the Arabic gum proportion of the mixtures rose.A reduction in the -OH bands may suggest a reduction in the pores or cavities in concrete where water can live.Nevertheless, the broad spectra of 3430 cm −1 also subjectively show the chemical hydration products containing a cluster of water molecules.The sharp, elongated OH peaks also indicate the presence of possibly hydrated reaction products in Arabic gum-cement mixture.The C-O-C (carbonate bands) of the cement mixtures may be observed around 1428 cm −1 , which corresponds to the asymmetric stretching of the CO 3 2group.The Al-O bonds are also visible in the spectral curves at 875 cm −1 , indicating the presence of alumino silicate (NASH and CaSH) phases in the cement mixture formed by the hydration reaction.Bands extending at 465 cm −1 and 795 cm −1 , respectively, can be used to visualize the Si-O-Si band (quartz).The decrease in the Si-O-Si peak shows stages of more highly reacted silica components in the cement mixture.

Scanning electron microscopy analysis
With Arabic gum additives, the SEM pictures reveal a microstructure that is denser and more compact than that of plain cement mix, which has less porosity and fewer pores in the matrix.The SEM images coupled with EDS of cement mixture samples are presented in figures 11 and 12.The cement mixture cured with water exhibited a looser structure with bigger pores.The cement mixture had a better pore structure, but contained some unreacted fly ash.A minor improvement in the microstructure density of the hydration products was observed.In addition to CSH and CH, the crystalline hydration products contain a few cube-shaped tobermorite crystals.The EDS analysis verifies that the formation is tobermorite with a Ca/Si ratio of less than 0.8.Aside from the reduction in porosity, the SEM image reveals that the microstructure of cement mixtures is denser with comparatively less pore structure.The Arabic gum additions demonstrated a considerable improvement in the microstructure of the cement demonstrating the efficiency of the curing technique in strengthening the cement matrix.Figure 11 displays the SEM images of the cement mixtures with different proportions of Arabic gum.As demonstrated, the cement mixture with Arabic gum exhibited a superior microstructure with fewer porosity.The reference cement mixture, which contained no bio-additives, possessed a compact microstructure, but EDS analysis confirmed the development of Ca(OH) 2 as the primary product.A substantial number of well-formed CH crystals were seen in the control cement mixture, demonstrating that the presence of voids and excess water allowed for CH crystal development.Moreover, the usage of Arabic gum in cement predominantly affected the microstructure via two separate methods.One is through the physical sheathing effect provided by the Arabic gum, which minimized the excess loss of water from the RPC during steam and autoclave curing, resulting in the  formation of CSH gels.FTIR spectrum curves reveal that the second mechanism is somewhat complex and involves chemical interactions with structural water that form compounds with the hydration product.Some of the Arabic gum molecules can also coat the cement grains, acting as a surface modifier for the fillers and allowing them to occupy the interfacial spaces without absorbing water, so limiting the shrinkage cracks that form in the cement matrix.The paste phase of any concrete is the weakest and most susceptible to cracking zone.Arabic gum interactions created a non-porous matrix structure and the EDS analysis reveals a Ca/Si ratio of 1.2, which corresponds to an increase in CSH synthesis.The Arabic gum addition in the cement mixture with more than 1% had the lowest Ca/Si ratio, with a value of 1.12.Despite the presence of enough water for hydration, the SEM micrograph of the cement mixture containing 1% Arabic gum revealed more holes and a less dense matrix structure.The freshly formed CSH binds to the surface between the grains, filling the interface and lowering the porosity to produce a compact structure.The decrease in porosity of the Arabic gum admixed cement mixture is caused by the bio-absorption of interstitial water by the polymer molecules, hence reducing the amount of free evaporable water.The curing effect can also be observed in the filling of pores by the hydration products of the cement paste.Later, when all the water is used by the concrete and there is insufficient water, the Arabic gum releases water molecules, resulting in excess CSH formations and inducing rehydration, which results in a more compacted interface.

Conclusions
The performance of cementitious composites is contingent upon their tensile strength, durability, and adaptability.In this study, a new composite consisting of cement and Gum Arabic is created and its properties are explored in depth.
i.With increased gum Arabic concentrations, cement mixes become less fluid, indicating improved particle bridging and attraction and less hydrolysis.The cement combination without gum Arabic bled the most, whereas the 1.5 percent gum Arabic mixture bled the least.
ii.Since the adsorption capacity of gum Arabic increases with time, making it ideal for use in cement systems, it is often added 15 min after the cement mixture has been mixed.An increase in the RH values at a fixed depth indicated that adding more gum Arabic had a curative effect on the cement from the inside out.
iii.The flexural strength performance of cementitious composites rose significantly as a function of gum Arabic proportion, and it can be concluded that the optimal proportion of Gum Arabic is 1%, resulting in a 17.3% improvement in flexural strength whereas 36.5% rise is found to be optimal at 1.25% in slant shear strength.In addition, no additional curing processes were necessary, and water curing was conducive to achieving enhanced characteristics.
iv.The co-polymers with very low sorptivity coefficient values decreased the porosity of the cementitious system, indicating a significant reduction in the size of capillary pores.
v. The creation of hydration products with greater strength and stability was also accompanied by a more compact interwoven matrix as a result of the interaction between Gum Arabic and cement particles, which strengthened the matrix.
vi.Consequently, the addition of Gum Arabic increased the essential properties of the cement composite and is extremely useful for application in cement-concrete interfaces with excellent performance.

Figure 1 .
Figure 1.Experimental images of performed samples.

Figure 4 .
Figure 4. Adsorption characteristics of GAr composites (a) mechanism (b) adsorbed values in mg/g.

Figure 12 .
Figure 12.SEM images of Arabic gum substituted autoclaved RPC mixes.

Figure 11 .
Figure 11.SEM image of autoclaved reference RPC mix.

Table 1 .
Oxide composition of cement.

Table 2 .
Chemical composition of Gum Arabic.