Ordinary Portland cement (OPC) remains the most common binder used in construction and accounts for nearly 7%-8% of the world’s CO2 emissions due to calcination of limestone and high energy use during clinker production. Reducing OPC content using SCMs is one of the major strategies to achieve sustainable construction. Stone-cutting dust, coming from quarrying activities and having a very fine particle size with oxide composition, has come out recently as a prospective SCM. Its chemical and mineralogical composition may vary widely depending on the type of parent rock: granite and basalt dusts, rich in silica and alumina, in contrast with marble and limestone dusts, which are mainly composed of crystalline calcium carbonate with low pozzolanic activity. This review aims to compile and discuss the published works concerning the use of SCD as a partial replacement of OPC, providing detailed information about its physicochemical, mechanical, and durability performance. Studies showed that 10%–25% replacement of OPC with SCD results in improvement in compressive strength (10%–20%), reduction of water absorption, and refinement of the pore structure due to the filler effect and limited pozzolanic reactivity. However, the obtained results are still inconsistent because of varying stone type, mix design, and curing conditions. Moreover, some reports show losses of strength or reduced workability when higher replacement levels were applied or in the case of using SCD enriched in carbonates. SEM, XRD, and FTIR studies demonstrated microstructural densification and secondary C–S–H in silica-rich systems, while calorimetric and long-term durability studies remain limited. Overall, SCD has the potential to be a promising sustainable supplementary cementitious material; however, its performance is strongly dependent on mineralogy and processing conditions. It is recommended that a standardized testing framework should be developed in order to allow better comparability between the various published studies and to guide safe and effective application in low-carbon cementitious systems.

Microbial-induced deterioration (MID) is a threat to the durability of cement-based materials (CBMs) particularly in sewer and wastewater systems. Whereas blended cements incorporating supplementary cementitious materials (SCMs) offer environmental benefits such as reduced carbon (IV) oxide (CO2) emissions and enhanced mechanical performance, their long-term resilience under microbial attack remains uncertain. The present systematic review synthesizes peer-reviewed literature from 2019 to 2026, selected from Scopus, Web of Science, ScienceDirect, and Wiley Online Library using rigorously defined search terms and stringent inclusion and exclusion criteria. The subsequent analysis divides the results into microbial mechanisms, the performance of the materials, and mitigation strategies, which can help create a comparative analysis between SCMs-rich systems and next-generation binders, in particular limestone-calcined clay cement (LC3). Experimental evidence shows that the mechanical properties of cementitious building materials are significantly reduced by microbial exposure. For example, OPC mortars exposed to Thiobacillus thioparus showed a 34% decrease in compressive strength after 90 days, while exposure to Acidithiobacillus thiooxidans showed strength losses of 19.9% in PPC and 39.8% in OPC mortars. Moreover, compressive strength reductions of up to 96% and dimensional changes of 11% in OPC specimens have been observed after prolonged exposure of these materials to sulfur-oxidizing bacterial cultures. Such findings highlight the importance of considering microbial activity in durability assessments of concrete structures. Incorporation of SCMs can reduce these adverse effects. Nanophase modified fly ash (FA) concretes, for instance, have negligible pH reduction and dimensional variation whereas calcium aluminate cement (CAC) mortars maintain a higher strength due to their inherent bacteriostatic properties. These observations suggest that SCMs not only alter the microstructure but also provide a degree of biochemical resilience against microbial attack. Though LC3 show great potential for microbial attack resistance due its alumina-rich hydrates and reduced portlandite content, there are still uncertainties about their buffering capacity and stability of carbonate phases in the presence of aggressive microbial environments. Mitigation strategies, such as coatings, biocidal additives and microbial-induced mineralization (MIM) have been evaluated with varying levels of efficacy, but their long term mechanical, microstructural as well as environmental compatibility with the SCMs and LC3 formulations are underexplored. This review identifies critical gaps in standardized microbial durability testing, LC3 performance evaluation, and sustainability assessments of mitigation strategies. Addressing these gaps is essential for developing bio-resilient, environmentally sustainable cementitious materials that support infrastructure resilience and align with the global sustainable development goals (SDGs).

This article focuses on lignin and its interaction with water, which is a critical aspect of various applications and modification of lignin. Efforts to formulate particleboards suitable in a moisturized environment have been a problem in manufacturing industries. Despite particleboards being cheap, water absorption and thickness swelling have been a challenge yet to be solved because it affects over time. Lignin being hydrophobic makes its interaction with water a subject of significant research, particularly regarding its potential as a sustainable and biodegradable material in various industries. The extraction methods of modifying the lignin structure to enhance its compatibility with water broaden its usability in creating water resistance and durable composites, which is discussed. The review paper also explores recent regulatory and market trends related to waste utilization and lignin valorization, addressing the challenges and opportunities in the field of green chemistry and lignocellulosic material. Green chemistry techniques of lignin modification as well as enhancing its mechanical properties are also discussed. Overall, the article suggests that understanding and manipulating lignin’s hydrophilic and hydrophobic properties can lead to significant advancements in sustainable material development while improving product durability in moisture-rich environments.

Fly ash is widely used as a supplementary cementitious material to reduce Portland cement consumption and enhance the long-term performance of cementitious composites. However, meaningful comparison of fracture toughness and durability reported across published studies remains challenging because of differences in specimen geometry, testing methods, curing conditions, and reporting practices. This review critically evaluates recent advances in the fracture toughness and long-term durability of fly ash–based cementitious composites through a structured synthesis of peer-reviewed studies published between 2020 and 2025. A normalization-based benchmarking framework was adopted to compare fracture and durability performance relative to corresponding control mixtures, thereby improving cross-study comparability. The review examines key fracture parameters, including critical stress intensity factor and fracture energy, together with durability indicators such as chloride permeability, sulfate resistance, freeze–thaw resistance, and carbonation depth. The synthesized evidence indicates that moderate fly ash replacement levels of approximately 25%–35% consistently provide the most balanced improvements in fracture resistance and durability through pore refinement, interfacial transition zone densification, and enhanced crack path tortuosity. In contrast, replacement levels exceeding approximately 40% may increase carbonation susceptibility under inadequate curing despite continued improvements in transport resistance. This review further integrates fracture mechanics, durability behavior, and microstructural evolution within a unified interpretation framework and identifies current research gaps, including the need for standardized fracture testing protocols and long-term field validation. The proposed benchmarking approach provides practical guidance for sustainable mix design and supports the development of more durable and resilient cementitious composites.

This study evaluates the physico-chemical performance of Ordinary Portland Cement (OPC) when partially replaced with stone-cutting dust (SCD), limestone (LS) and natural pozzolana (NP), both individually and in ternary combinations. Blends were formulated with SCD and NP at 10-40% and LS at 5-20%, including optimized ternary mixtures. Tests focused on normal consistency, setting time and water sorptivity. Results showed that all supplementary cementitious materials (SCMs) increased normal consistency, from 28.0% in OPC to 35.0% at 40% substitution. Setting time was significantly extended in SCM-rich blends, with initial and final setting times reaching up to 250-260 minutes, compared to 100 and 180 minutes for OPC. This delay, especially in NP and SCD-rich mixtures, reflects reduced reactivity and higher water requirements. Water sorptivity improved in optimized ternary blends, with Mix H (10% SCD + 10% LS + 15% NP) showing the lowest sorptivity coefficient of 0.1666 g/cm2/hr0.5, compared to 0.1908 for OPC. These findings demonstrate that carefully balanced combinations of NP, LS and SCD enhance workability, provide longer setting windows and reduce water ingress, leading to improved durability. The results support the use of locally available materials in Kenya as sustainable and cost-effective alternatives for blended cement production.

The world’s growing population and industrialization have led to increased construction activities. This has increased the amount of waste aggregates which can be recycled in construction and cut the cost of infrastructure development. This study, therefore, reports the experimental findings for the effect of immobilizing Bacillus megaterium on the compressive strength and water absorption of laboratory prepared test mortar. Bacterial solution used in this work had a concentration of 1.0 × 107 cells/mL. The impact of recycled mortar impregnated with bacteria was studied after curing the specimens in water, saturated lime water, and 1.5% sulfuric acid. Compressive strength for test specimens cured in the three media was determined at the 2nd, 7th, 28th, and 56th day of curing. SEM analysis was done for mortars cured in acidic media and saturated lime water after curing for 28 days. The test results indicated that curing in water and saturated water improved the compressive strength, while the acidic medium lowered it. Recycled mortar is, therefore, an ideal material for immobilizing Bacillus megaterium before introduction into fresh concrete/mortar. The use of recycled mortar is a good strategy to reduce wastes from construction activities, save on the cost of construction materials, and enhance environmental conservation.

ABSTRACTMicrobiologically induced calcium carbonate precipitation, (MICCP) is a natural biogeochemical process driven by microorganisms upon interacting with a calcium-rich solution under favourable conditions. In this study, three bacterial Bacillus species, Sporosarcina pasteurii, Lysinibacillus sphaericus and Bacillus megaterium were incorporated in fresh mortar paste that was used in mortar prisms fabrication. The bacterial endospores were cultured in solutions containing either calcium chloride or calcium ethanoate as the Ca2+ source. The calcium carbonate polymorphs produced by the various bacteria under study were analyzed by scanning electron microscopy and X-ray diffraction. The calcium carbonate precipitated in the control mortar as observed via XRD could be attributed to carbon (IV) oxide biogenic mechanism. Calcium acetate used as the Ca2+ source precipitated the metastable vaterite polymorph through autotrophic pathway regardless of the embedded Bacillus bacterial species. Calcium chloride in presence of urea precipitated calcite on embedding Sporosarcina pasteurii via heterotrophic pathway. MICCP can be used for remediation and durability enhancement to a variety of cement-based construction materials based on the polymorph precipitated.

This paper reports study findings on the use of Lysinibacillus sphaericus (at 1.0 × 107 cells/ml concentration) to enhance and improve the physicomechanical and chemical properties of blended Ordinary Portland Cement (OPC). Blending was done separately with pulverized fly ash (PFA) and natural pozzolana (volcanic tuff) at substitution levels of 10%, 20%, 30%, 40%, 50%, 60%, and 70%. Mortar prisms of dimensions 40 mm by 40 mm by 160 mm were prepared and cured for the 2nd, 7th, 28th, 56th, and 90th days using Lysinibacillus sphaericus solution as mixing water and curing media. Commercial OPC and PPC mortar prisms cast and cured using distilled water were used as controls. Results showed that prisms treated with bacteria exhibited the highest performance on compressive strength development. Further microstructure analysis of blended cement incorporated with Lysinibacillus sphaericus bacteria showed significant amounts of reacted secondary cementitious materials compared to samples without bacteria. Bacteria presence was also found to reduce water demand during mixing and setting times and exhibited low porosity in relation to samples without bacteria. These results showed that the presence of alkaliphilic bacteria in the blended cement resulted in synergistic effect in enhancing the physicochemical and mechanical properties.

Cement is widely used as a construction material in the construction industry. However, there are challenges affecting its durability efficacy. Cement mortar/concrete is subject to degradation by aggressive ions such as sulphates and chlorides. Sulphates can be introduced into the concrete or mortar by Sulphur producing bacteria of the species Thiobacilli. Microbiologically induced CaCO3 precipitation (MICP) has found its application in bioremediating cement based materials. It has been found to be environmental friendly. However, no work has been reported on bioremediation of biodegraded cement based materials. This paper presents findings of possible bioremediation of mortars after undergoing biodegradation. Bacillus flexus, a beneficial bacterium was used. The control mortars were prepared using Ordinary Portland Cement (OPC). The test mortars were prepared and cured in a solution of Thiobacillus thioparus, a Sulphur oxidizing bacteria, deleterious bacterium for 14, 28, 56 and 90 days. Compressive strength analysis was conducted on the 14th, 28th, 56th and 90th day of curing. Results showed that the lowest compressive strength was recorded on the 90th day as 31.02 MPa. This was a 34.17 % loss in compressive strength. Another category of mortar cured in Thiobacillus thioparus for 28 days was bioremediated for 28 days using Bacillus flexus solution. Compressive strength and Scanning Electron Microscopy (SEM) analyses were then done. The results show a compressive strength of 45.83 MPa at the 56th day. This represents a 99.91 % strength recovery from biodeterioration. The SEM analysis results revealed a denser material. This was due to massive precipitation of calcium carbonate in the mortar matrix and pores/voids for bioremediated mortars as opposed to the biodegraded mortars. The results further revealed reduced ettringite crystals on the bioremediated mortars. Bacillus flexus could perhaps be used in restoring lost compressive strength as well as in sealing voids in degraded concrete in sewer lines and other cement based materials. This could improve on its efficacy with minimal repair.

Aims To determine the effect of direct embedment of Bacillus megaterium into Portland pozzolana cement mortars on water sorptivity and diffusivity coefficient of sulphate ions. Methods and Results Prisms with a water/cement ratio of 0 center dot 5 were prepared by blending Portland Pozzolana cement with the requisite volume of a B. megaterium (microbial) solution whose concentration was 1 center dot 0 x 10(7) cells per ml. Mortar prisms of 160 mm x 40 mm x 40 mm were fabricated for this study. Mortars cured for 28 days were exposed to 0 center dot 2465 mol l(-1) Na2SO4 solution using accelerated ion migration test method for 36-h session using a 12V DC power source. Sulphate ion concentration was then determined through the ingressed mortar at 10 mm interval. A minimum water sorption gain of 0 center dot 61% was observed on the prism prepared with and cured in microbial solution. A maximum of 0 center dot 0289 and a minimum of 0 center dot 0093 water sorptivity coefficients were exhibited by the control prism and microbial prisms, respectively. The microbial prisms exhibited the lowest apparent diffusion coefficient (D-app) of 4 center dot 5179 x 10(-11) m(2) s(-1). Conclusions Direct incorporation of B. megaterium in mortar preparation, curing or both regimes significantly retarded water sorption and lowered sulphate ion ingress. The inclusion of this bacterial in the mortar further complements the pozzolana pore structure benefits. Significance and Impact of the Study This novel B. megaterium bacteria which can survive and cause biocementation within hydrating cement mortar when not encapsulated would result in a green innovation. Once adopted and applied in real-life scenario, it would promote construction of durable, safe, resilient and affordable shelter.

The concrete/mortar durability performance depends mainly on the environmental conditions, the microstructures, and its chemistry. Cement structures are subject to deterioration by the ingress of aggressive media. This study focused on the effects of Bacillus megaterium and Lysinibacillus sphaericus on flexural strength and chloride ingress in mortar prisms. Microbial solutions with a concentration of 1.0 × 107 cells/ml were mixed with ordinary Portland cement (OPC 42.5 N) to make mortar prisms at a water/cement ratio of 0.5. Four mortar categories were obtained from each bacterium based on mix and curing solution. Mortar prisms of 160 mm × 40 mm × 40 mm were used in this study. Flexural strength across all mortar categories was determined at the 14th, 28th, and 56th day of curing. Mortars prepared and cured using bacterial solution across all curing ages exhibited the highest flexural strength as well as the highest percent flexural strength gain. Lysinibacillus sphaericus mortars across all mortar categories showed higher flexural strength and percent flexural strength gain than Bacillus megaterium mortars. The highest percent flexural strength gain of 33.3% and 37.0% was exhibited by the 28th and 56th day of curing, respectively. The mortars were subjected to laboratory prepared 3.5% by mass of sodium chloride solution under the accelerated ion migration test method for thirty-six hours using a 12 V Direct Current power source after their 28th day of curing. After subjecting the mortar cubes to Cl media, their core powder was analyzed for Cl content. From these results, the apparent diffusion coefficient, Dapp, was approximated from solutions to Fick’s 2nd Law using the error function. Bacillus megaterium mortars across all mortar categories showed lower apparent diffusion coefficient values with the lowest being 2.6456 × 10–10 while the highest value for Lysinibacillus sphaericus mortars was 2.8005 × 10–10. Both of the test bacteria lowered the ordinary Portland cement Cl-ingress but Bacillus megaterium was significantly more effective than Lysinibacillus sphaericus in inhibition.

Most of concrete structural failures are attributed to poor workmanship and poor engineering designs. Some microorganisms present in sewer systems can degrade the concrete and/or mortar. Concrete failures due to microbial attack has not attracted much attention especially in developing countries such as Kenya. This study investigated the effect of Thiobacillus intermedius bacteria on the performance of Ordinary Portland Cement (OPC). Preparation of test mortar prisms was done using the bacterial solution as either mix water, curing water or both. The control mortar prisms were prepared and cured in distilled water. Compressive strength test was done after 7th, 28th, 56th and 90th days of curing respectively. Results showed significant drop in compressive strength for the mortar prisms prepared and cured in bacterial solution as compared to the control mortar samples. Soundness and normal consistency increased significantly for the bacterial treated cement paste as compared to the control sample. Scanning Electron Microscopy (SEM) analysis showed severe damage on the bacterial treated cement mortar. This was characterized by formation of deleterious expansive products like ettringite and gypsum. Control mortar sample exhibited even formation of hydration products within the pore system.

Conventional binders in the particleboards formulation involve use of formaldehyde resins. Epidemiologic studies show that formaldehyde is carcinogenic. Efforts to reduce formaldehyde emissions by use of scavengers has not been proven to reduce the emission. Molecular bonding of biobased adhesive molecules with lignocellulose materials provides an alternative way of producing composite material. In this study, maize stalk (MS), rice husks (RH) and sugarcane bagasse (SB) were used as sources of lignocellulose materials for particleboard formulation. SB, MS and RH were collected from their respective sites, sorted and dried. MS and RH were ground. Lignin content determination was done by drying lignocellulose material at 105 °C. Lignocellulose materials were prepared by hydrolysis of dried lignocellulose material with sodium hydroxide. Oxidized starch was prepared by oxidation of cassava peel starch using alkaline hydrogen peroxide. Particleboards were formulated through starch-lignocellulose polymerization at 60 °C compressed with 6.5 Nmm−2 pressure. Characterization of raw materials and formulated particleboards was done using XRD for mineralogical analysis, FTIR and NMR for elucidation of functional groups transformation. The results showed that esterification is the main process of chemical bonding in the particleboard formulation due to reaction between –COOH from starch and and OH- from lignocellulose. Etherification between hydroxyl groups from starch with hydroxyl groups from lignocellulose material. RH combined more through silication process with cassava peels starch than RH and SB showing materials containing high cellulose and hemicellulose content are more compatible. Composite materials formulated were used to produce medium density particleboards that can be used for making furniture and room partitioning.

Efforts to reduce pressure on use of wood in particleboard formulation have included the use of non-wood materials such as crop residues. Physical and mechanical properties are determined by the number of the hydroxyl (-OH) groups. Hydroxyl (-OH) groups attracts water molecules through hydrogen bonding affecting water absorption (WA) and thickness swelling (TS). WA and TS affect curing process of adhesive. Curing process of adhesives affects the mechanical characteristics of formulated particleboards. These challenges have been acted upon continuously through research. This review paper presents crop residues used as alternative lignocellulose material source in particleboard formulation and the various advances that have been made to improve on the properties of the resultant particleboards. Improvement over time of the non-wood material in composite materials focusses on increasing water resistance and compatibility between lignocellulose and binder. Crop residues-based are used in making medium and low density particleboards. These boards have shown good mechanical characteristics which include modulus of rupture (MOR), modulus of elasticity (MOE) and internal bonding (IB). MOR, MOE and IB have over time been improved by enhancing chemical compatibility of lignocellulose material and the binders. Water absorption and thickness swelling remain challenge. This review paper further explored various methods of improving water absorption and thickness swelling of crop-residue based particleboards.

Concrete structures placed in aggressive aqueous environments are vulnerable to degradation. Majority of studies have linked structural failures to the ingress of deleterious ions into the cement matrix. Some microbial activities may accelerate the penetration of harmful materials into the cement matrix and hence cause pronounced deterioration. This work reports a laboratory-simulated study carried out to determine the extent of chloride ingress in cement mortars exposed to Acidithiobacillus thiooxidans. Test prisms were cast from Portland pozzolana cement (PPC) and ordinary Portland cement (OPC) with water-to-cement ratio maintained at 0.5. Acidithiobacillus thiooxidans bacterial solution of concentration 1.0×107 cell/mL was used to prepare microbial mortar prisms, whereas distilled water was used to prepare the control mortar prisms. The test prisms were subjected to porosity and accelerated chloride ingress after 28th day of curing. Compressive strength was determined after the 2nd, 7th, 28th, and 56th days of curing. Apparent diffusion coefficients (Dapp) were estimated from the solutions to Fick’s second law of diffusion. After the 56th day of curing, the microbial-treated mortars exhibited a significant reduction in compressive strength. The resultant percentage decrease in compressive strength was 30.74% and 19.88% for OPC and PPC, respectively. Further, microbial-treated mortars demonstrated both high porosity and chloride ingress as compared to the control test mortars. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses showed the formation of new deleterious products in the microbial-exposed mortars.

Formaldehyde-based resins are conventionally used as a binder in formulation of particleboard. Epidemiologic studies have shown that formaldehyde is carcinogenic. Efforts to reduce the health hazard effects of the fomaldehyde-based resin in the particleboard formulation have included use of scavengers for formaldehydes and use of an alternative binder. Use of scavengers for the formaldehyde increases the cost and maintenance of particleboard formulation. There is no proof that scavengers eliminate the emission of formaldehyde from particleboard. Use of biobased binders in particleboard formulation provides an alternative for eliminating use of the formaldehyde-based resin. However, the alternative is hindered by challenges, which include limitations of physical and mechanical properties. The challenge has continuously been acted upon through research. The paper presents an overview of the use of starch as an alternative binder. Improvement over time of the starch and limitations thereof requires to be addressed. Use of the modified starch has shown increased particleboard performance. Mechanical strength, such as modulus of rupture, modulus of elasticity, and internal bonding in particleboards, however, remains to be a challenge.

This paper reports leach and/or intake of SO42−, Cl−, Ca2+, Na+, and K+ from and/or into cement mortar cubes made from a novel cementious material in naturally encountered environmental simulated media. The paper also reports changes in pH of the media over time of exposure to the cement mortar cubes. The compressive strength changes of the test cement in simulated media are also reported. The novel cement, labelled PCDC, made from intermixing ordinary Portland cement (OPC) with waste materials which included rice husks, waste bricks, acetylene lime sludge, and spent bleaching earth was previously tested and found to meet the Kenyan Standard requirements for Portland pozzolana cement (PPC). 100 mm mortar cubes were prepared, and their compressive strengths were determined after exposure to the sea water. The media included sea water, distilled water, and solutions of sulphates and chlorides separately for a period of six months. The tests were carried alongside commercial PPC and OPC. The results showed that the PCDC exhibited comparable selected ions intake and/or leach to PPC in sea water, sulphate solutions, and distilled water. In chloride solutions, the cement exhibited the highest leach in the selected ions except K+ and Na+ ions. The results further showed that PCDC exhibited lower pH in all the media compared to OPC and PPC. The tests showed that the novel cement can be used for general construction work in the tested media in a similar manner to PPC.

Cement structures are subject to degradation either by aggressive media or development of micro/macro cracks which create external substance ingress pathways. Microbiocementation can be employed as a self-intelligent solution to this deterioration process. This paper presents study results on the effects of Lysinibacillus sphaericus microbiocementation on Ordinary Portland cement (OPC), normal consistency, setting time, soundness, compressive strength and water sorptivity. Microbial solutions with a concentration of 1.0 × 107 cells/ml were mixed with OPC to make prisms at a water/cement ratio of 0.5. Mortar prisms of 160 mm × 40 mm x 40mm were used in this study. A maximum compressive strength gain of 17% and 19.8% was observed on the microbial prism at the 28th and 56th day of curing respectively. A minimum of 0.0190 and a maximum of 0.0355 water sorptivity coefficient was observed on the OPC microbial prism and OPC control prism, after 28th day of curing respectively. Scanning electron microscope images taken after the 28th day of curing showed formation of vast calcium silicate hydrates and more calcite deposits on microbial mortars. Statistical findings of this study indicate that Lysinibacillus sphaericus significantly retarded both the setting time and normal consistency, but has no influence on the mortar soundness.

Deleterious ions in the environment such as sulfates may degrade the concrete structures. The interaction of cement hydration products with these destructive agents contributes to severe durability threat of the concrete structures. External sulfate attack is well-known for causing permanent changes in concrete. Microbially induced calcium carbonate (MICP) precipitation has been considered as a unique technique in enhancing the durability properties of concrete. This review paper discusses the possibility of bio-deposition from MICP process as a barrier in microbial treated concrete against the penetration of sulfate ions in a sulfate- rich environment. The effect associated with chemical and physical sulfate attack is discussed in line with the mechanical properties of cement such as compressive strength whereas microscopic evaluation is based on scanning electron microscopy studies. The shortcomings associated with sulfate ions in cement-based materials and the positive effects of incorporating bacillus species bacteria in sulfate rich areas is discussed. This review found that, MICP can significantly reduce the ingress of sulfate ions in cement-based materials, which results in improving the mechanical properties of the cement mortar/concrete.

Conventional methods of making particleboards utilize wood chips. This has resulted in a decrease in the tree cover due to the increase in wood demand. The effect has been climatic change. Wood is bound using phenol formaldehyde resin. Because of the decrease in the forest cover, alternative lignocellulose materials are required. In this study, lignocellulose materials used include sugarcane bagasse, maize stock, and rice husks. The cassava-starch mix with borax was used as a binder in particleboard formulation. The lignin content was determined, and its effect on properties of boards was investigated. The resultant composite material was molded at a pressure of 6.5 N/mm2 and at 30°C. The resultant particleboards had mean densities ranging from 0.604 to 0.611 g/cm3. The modulus of elasticity ranged from 2364.2 N/mm2 to 3329.93 N/mm2, modulus of rupture ranged from 13.55 N/mm2 to 14.83 N/mm2, and internal bonding ranged from 1.613 N/mm2 to 2.370 N/mm2. The performance of the board was dependent on the lignocellulose material used. Fourier transform infrared spectroscopy analysis showed that main chemical bonding in the particleboard resulted from esterification of –COOH from lignocellulose and OH- from starch. The particleboards formulated were found to be of low-density-fibre standard used in a similar manner to the conventional low-density particleboards.