Construction and Building Materials最新文献

{"title":"Ultrafast-setting magnesium phosphate cement prepared from low-burned magnesium oxide for mixed stirring extrusion function integrated 3D printing applications","authors":"Yongjie Deng ,&nbsp;Nan Li ,&nbsp;Jianjun Zhong ,&nbsp;Yun Liang ,&nbsp;Libo Lyu ,&nbsp;Qiuchun Yu ,&nbsp;Weihong Li","doi":"10.1016/j.conbuildmat.2025.141537","DOIUrl":"10.1016/j.conbuildmat.2025.141537","url":null,"abstract":"<div><div>Regarding the issues of high cost, energy consumption and low activity in the existing preparation of magnesium phosphate cement (MPC) using heavy-burned magnesium oxide as raw material, this paper aims to prepare ultrafast-setting MPC using low-burned magnesium oxide. The objective was to explore the laws and mechanisms by which different magnesium oxide calcination temperatures affect the setting time, compressive and bond strengths, volumetric stability, and microstructure of MPC, thereby determining the optimal calcination temperature of magnesium oxide. Then, taking the setting time and compressive strength as performance indices, this paper determines the optimal baseline values of each component of MPC. Specifically, it ascertains the magnesium-phosphorus ratio, water-binder ratio, and borax doping amount. Subsequently, it integrates with the Mixed Stirring Extrusion Function Integrated 3D (MSEFI-3D) printing process to realize the application of MPC. The results reveal that, in comparison with MPC prepared from traditional heavy-burned magnesium oxide, appropriately reducing the calcination temperature of magnesium oxide can effectively enhance the mechanical properties of MPC and improve its volume stability. The compressive strength and interfacial bonding strength of MPC reach their optimal values when the calcination temperature of magnesium oxide is within the range of 850–950°C. Furthermore, the MPC prepared at this calcination temperature demonstrates excellent extrudability and constructability during the printing process. It can satisfy the requirements of 3D printing, thus providing a reference for the 3D-printing application of ultrafast - setting MPC prepared from low - burned magnesium oxide.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"479 ","pages":"Article 141537"},"PeriodicalIF":7.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Composite toughened cement stabilized macadam with rubber/PVA fiber: Deformation, durability and stress evacuation effect","authors":"Chaohui Wang ,&nbsp;Haowen Xue ,&nbsp;Penghui Wen ,&nbsp;Feng Chen ,&nbsp;Ke Yi","doi":"10.1016/j.conbuildmat.2025.141487","DOIUrl":"10.1016/j.conbuildmat.2025.141487","url":null,"abstract":"<div><div>To enhance the toughness of cement-stabilized macadam (CSM) base and improve its resistance to cracking and durability, rubber/ Polyvinyl Alcohol (PVA) fiber CSM was prepared. Techniques for the pre-treatment of rubber particles and PVA fibers were proposed. The deformation characteristics of rubber/PVA fiber CSM were systematically studied. The heat transfer rules under different conditions were revealed. The fatigue performance and frost resistance of rubber/PVA fiber CSM were clarified. The flexural performance and stress evacuation effect of rubber/PVA fiber CSM were elucidated. The results indicate that, compared to CSM, PVA fiber CSM, and rubber CSM, the dry shrinkage strain of rubber/PVA fiber CSM can be reduced by 14.1–38.9 %. The average temperature shrinkage coefficient can be reduced by 21.5–58.3 %. In comparison to CSM, rubber/PVA fiber CSM exhibits a 16.6 % reduction in temperature difference during heating and a 23.0 % reduction during cooling. The mass loss rate and unconfined compressive strength (UCS) loss rate after freeze-thaw cycles of rubber/PVA fiber CSM are effectively mitigated. The fatigue life at different stress levels can be increased by 30.8–80.4 %, and the critical flexural strain energy density can be improved by 18.8–63.6 %. After complete cracking, the strain can be reduced by 42.8–54.3 %, resulting in the smallest crack propagation area, which effectively evacuates the internal stress of the base and delays crack development.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"479 ","pages":"Article 141487"},"PeriodicalIF":7.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of field compaction curves for asphalt mixtures based on laboratory workability tests and machine learning modeling","authors":"Zhen Liu ,&nbsp;Shihui Shen ,&nbsp;Shuai Yu ,&nbsp;Behnam Jahangiri ,&nbsp;David J. Mensching ,&nbsp;Hamzeh F. Haghshenas","doi":"10.1016/j.conbuildmat.2025.141520","DOIUrl":"10.1016/j.conbuildmat.2025.141520","url":null,"abstract":"<div><div>A clear understanding of asphalt mixtures' workability and compactibility is crucial for optimizing field compaction and mix designs. However, the standard laboratory gyratory compaction test alone often fails to accurately describe in-situ compaction behaviors, leaving a gap between laboratory and field compaction. This paper proposes an innovative yet practical approach to developing field compaction curves and estimating field compaction behavior using laboratory workability test data. A hypothesis of <em>Rotation for Effective Compaction</em> was first introduced, considering particle rotation as an effective parameter linking laboratory and field compaction. It suggests that the trend of particle rotational motion, under given compaction energy, remains consistent across both laboratory and field conditions. Materials from four lanes of the FHWA Turner-Fairbank Highway Research Center (TFHRC) Pavement Testing Facility (PTF) 2023 project were tested using MixWorx™ sensor in accordance with ASTM D8541. An AutoML method was applied for optimizing machine learning models. It identified LightGBM as the optimal model for predicting the field compaction curve, achieving 95.7 % classification accuracy for compaction levels and a 98.4 % R² fit for density prediction. Validation with field sensing and compaction data from Altoona, PA, and Angola, IN projects confirmed model robustness and hypothesis validity. This method offers a promising tool for optimizing asphalt mixture design and identifying workability issues.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"479 ","pages":"Article 141520"},"PeriodicalIF":7.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multi-scale insights into the adhesion of steel slag-asphalt interface influenced by hydration process","authors":"Jun Zhang ,&nbsp;Naisheng Guo ,&nbsp;Shichao Cui ,&nbsp;Guangshuai Wu ,&nbsp;Jiayu Liang ,&nbsp;Zhanping You","doi":"10.1016/j.conbuildmat.2025.141508","DOIUrl":"10.1016/j.conbuildmat.2025.141508","url":null,"abstract":"<div><div>Steel slag, a byproduct of the steelmaking process, exhibits poor volumetric stability in its freshly produced or untreated state, which significantly restricts its application in pavement engineering. Currently, weathering is the predominant process for treating steel slag. A multi-scale approach was employed to investigate the mechanism of hydration reactions on the adhesion properties of the steel slag-asphalt interface during the weathering process in this study. The effects of hydration on adhesion properties were evaluated through modified boiling tests and surface free energy (SFE). The surface morphology of unhydrated and hydrated steel slag was compared using scanning electron microscopy (SEM) and optical profilometry. The adhesion properties of asphalt at the interfaces with unhydrated steel slag (C₃S and C₂S), hydrated steel slag (CaCO₃), and basalt (SiO₂) were systematically analyzed using molecular dynamics (MD) simulations, incorporating static, pull-off, and novel dynamic water scouring models to simulate diverse environmental conditions. The results indicated that the mass loss rate (MLR) and peeling rate (PR) of hydrated steel slag after a 10-minute boiling test were 1.3 and 2.2 times higher than those of unhydrated steel slag, respectively. Meanwhile, hydration treatment reduced the adhesion work between steel slag and asphalt by 2.0 % and increased the peeling work by 33.5 %. SEM images and 3D surface topography analyses showed that hydration transformed the rough-textured structure on the steel slag surface into a loose honeycomb structure, resulting in an increase of 6.42 % in arithmetic average roughness (Ra) and 8.84 % in root mean square roughness (Rq). MD simulations demonstrated that the mean square displacement (MSD), diffusion coefficient (DC), and z-value of relative concentration (RC) peaks of asphalt on the CaCO₃ surface were greater than those on C₃S and C₂S, while the interface interaction energy, adhesion work, and cohesion ratio (CR) were lower. Under water molecule scouring, the simulated peeling rate (SPR) of asphalt on the CaCO₃ surface increased by 34.5 % compared to C₃S but decreased by 7.7 % compared to C₂S. Furthermore, there was a strong correlation (<em>r</em> &gt; 0.8) between the experimental and simulation data.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"480 ","pages":"Article 141508"},"PeriodicalIF":7.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study on the enhancement of physical properties of coral aggregates through superfine cement paste suction under negative pressure","authors":"Xu He ,&nbsp;Jikai Zhou ,&nbsp;Jianjun Wei ,&nbsp;Bangyong Yu ,&nbsp;Kaisheng Xu ,&nbsp;Minjun Cao","doi":"10.1016/j.conbuildmat.2025.141474","DOIUrl":"10.1016/j.conbuildmat.2025.141474","url":null,"abstract":"<div><div>In marine civil engineering, the pore characteristics and mechanical properties of coral aggregates limit their application in construction engineering. This paper experimentally explored a paste suction technology aimed at enhancing the physical properties of coral aggregate. This study initially prepared superfine cement paste, which was used to be suctioned into the coral pores by negative pressure. Subsequently, the crush resistance, density, porosity, permeability resistance, and microstructures of coral aggregate were investigated before and after paste suction. The study found that this technology enabled the suction of superfine cement paste into the coral pores, thereby reducing the porosity of the coral and significantly enhancing the mechanical properties and permeability resistance of the coral aggregate. To ensure the optimal enhancement effect on the coral, the prepared paste needed to prioritize ensuring fluidity before increasing mechanical strength. However, when the fluidity reached the threshold, further increasing the strength of the paste resulted in a more pronounced improvement in the physical properties of the coral aggregate. The improvement of coral permeability resistance could be achieved through two approaches: either by increasing the thickness and compactness of the paste coating the outer surface of the coral, or by enhancing the amount and compactness of the paste suctioned into the internal pores of the coral. Microscopic experiments further revealed that coral exhibits three types of pore structures. Coral with well-connected and uniformly distributed pores demonstrated the most significant performance improvement due to paste suction, whereas coral with a large number of closed pores and micropores exhibited limited enhancement effects. However, for coral concrete applications, the paste suction technology was feasible and effective in enhancing the mechanical properties and permeability resistance of coral aggregate.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"479 ","pages":"Article 141474"},"PeriodicalIF":7.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multiscale characterization of bond performance of UHPC-NC with different interface agents","authors":"Yanzhi Wang ,&nbsp;Pizhong Qiao ,&nbsp;Jing Sun ,&nbsp;An Chen","doi":"10.1016/j.conbuildmat.2025.141436","DOIUrl":"10.1016/j.conbuildmat.2025.141436","url":null,"abstract":"<div><div>The interface bonding properties of bi-material structures are influenced by a variety of factors, including surface roughness, presence of interface agents, moisture content of surface, etc., and they are critical factors in determining the overall performance and durability of structures. Interface between dissimilar materials exhibits heterogeneity and discontinuity. In this study, four types of interface agents (i.e., epoxy resin, nano-epoxy resin, high-strength mortar, and fiber-reinforced mortar) are proposed to investigate the multiscale effect and bonding mechanism of interface heterogeneity and continuity on the bond performance between hybrid recycled tire steel fiber reinforced concrete or ultra high performance concrete (UHPC) and normal strength concrete (NC). The multiscale analyses include the macroscopic (i.e., surface morphology, tensile bond strength, and shear bond strength), mesoscopic (i.e., fiber distribution, size of interface transition zone, and pore structure), and microscopic (i.e., micro-morphology and hydration product characteristics) characterization. The findings indicate that improving the interface heterogeneity and continuity enhances the bond performance of UHPC-NC interface. Compared with the reference group without the interface agent, the samples reach the highest tensile and shear bond strength, which are 71.46 % and 150 % higher than those of the reference ones, respectively, when the chemical interface agent with similar components and properties between the UHPC-NC layers is deployed. The present study reveals that the improvement in interface bond performance is attributed to the formation of hydration products and the densification of interface transition zone, governed by the chemical bonding, fiber reinforcement, and physical adsorption effects. Furthermore, the relationship between the size of interface transition zone and interface bond strength is established. Based on the theory of stress wave propagation, the influencing mechanism of interface heterogeneity and continuity on the failure mode and bond performance of UHPC-NC composites is elucidated. It concludes that altering the interface continuity between the UHPC-NC layers is the key to control the interface bond strength and its failure modes.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"480 ","pages":"Article 141436"},"PeriodicalIF":7.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on freeze-thaw failure mechanism of rubberized concrete and analytical evaluation of the damage evolution","authors":"Xiaoyan Han ,&nbsp;Zihan Zhang ,&nbsp;Dubo Wang ,&nbsp;Aijiu Chen ,&nbsp;Yanting Ji ,&nbsp;Zhihao Wang ,&nbsp;Qing Zhang ,&nbsp;Youqin Lu ,&nbsp;Hui Li ,&nbsp;Linhua Jiang","doi":"10.1016/j.conbuildmat.2025.141511","DOIUrl":"10.1016/j.conbuildmat.2025.141511","url":null,"abstract":"<div><div>A robust evaluation of freeze-thaw damage in concrete is essential for precise design and risk assessment of frost resistance in related structures, maximizing the benefits of rubberized concrete's frost resistance. This study aims to accurately and robustly describe the evolution of freeze-thaw damage in rubberized concrete subjected to freeze-thaw cycles through the implementation of standardized testing processes. The study observed a significant impact of crumb rubber on concrete frost resistance. Specifically, the number of freeze-thaw cycles that the RC3 specimens withstood reached up to 275, which is 100 and 50 cycles greater than that of normal concrete and air-entrained concrete specimens, respectively, at the point of failure. Additionally, pretreating crumb rubber further delays the damage in rubberized concrete. When RC1–RC5 were deemed failed, the value of <em>P</em>_<em>n</em> for KRC1–KRC5 increased by 5.9–17.9 % compared to that of RC1–RC5, with a maximum reduction in <em>W</em>_<em>n</em> of 2.0 %. The alterations in the pore structure of concrete due to the incorporation of crumb rubber were found to significantly influence frost resistance. This study clarifies the freeze-thaw damage mechanism of rubberized concrete, highlighting the differences in pore structure characteristics and the evolution patterns of the rubberized concrete matrix under freeze-thaw cycles compared to conventional concrete matrices. A comprehensive analysis led to the development of equations for <em>η</em>_m, <em>E</em>_dt<em>n</em>, and <em>ψ</em>_<em>n</em> related to the frost resistance of rubberized concrete, presenting a new set of robust evaluation equations for assessing freeze-thaw damage and frost resistance durability life.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"480 ","pages":"Article 141511"},"PeriodicalIF":7.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887899","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive analysis of pre-crack parameters on repeated impact strength and failure mechanism: Effects of crack depth, length, and position in engineering cementitious composites","authors":"Sallal R. Abid ,&nbsp;G. Murali ,&nbsp;Sajjad H. Ali","doi":"10.1016/j.conbuildmat.2025.141515","DOIUrl":"10.1016/j.conbuildmat.2025.141515","url":null,"abstract":"<div><div>Assessing the impact resistance of engineering cementitious composites (ECC) is essential for applications that demand exceptional durability under impact loading conditions. The impact testing method developed by the American Concrete Institute (ACI) Committee 544 has traditionally been employed to evaluate the concrete impact resistance. However, current research predominantly focuses on uncracked specimens, with limited attention given to the effect of pre-existing cracks on the repeated impact strength and failure mechanisms. This study attempts to examine the impact of pre-crack depth, length, and location on the impact behavior of ECC specimens, utilizing ACI impact test specimens with intentionally introduced pre-cracks. This study presents an innovative approach by investigating 17 distinct pre-cracked specimen configurations, with cracks positioned at the bottom and impact loads applied to the top, where no predefined cracks are present. This unique specimen arrangement represents a significant contribution to the current research. The polypropylene fiber was used to prepare the ECC at 2 % dosage. Additionally, the impact strength was presented in terms of reliability by analysing the data dispersion using the Weibull distribution. Results indicate that increasing crack depth significantly reduces the impact strength of ECC specimens. Specifically, for a central full-length pre-crack, initial cracking and failure impact numbers decrease by up to 89.81 % and 78.00 %, respectively, as crack depth increases from 15 mm to 45 mm. This demonstrates an inverse relationship between crack depth and tensile performance, with deeper cracks impairing load distribution efficiency. Pre-crack location significantly influences impact resistance. Eccentric cracks (e.g., 50 mm from the centerline) result in smaller reductions in impact strength compared to centrally located cracks.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"479 ","pages":"Article 141515"},"PeriodicalIF":7.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891255","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bond strength and load-carrying capacity of GFRP rebars embedded in concrete: An experimental and analytical study","authors":"Behnaz Arefian,&nbsp;Davood Mostofinejad","doi":"10.1016/j.conbuildmat.2025.141512","DOIUrl":"10.1016/j.conbuildmat.2025.141512","url":null,"abstract":"<div><div>The increasing adoption of glass fiber-reinforced polymer (GFRP) rebars in concrete structures necessitates a thorough understanding of their bond behavior. This research presents an experimental and analytical study focused on the bond behavior and load capacity of GFRP bars embedded in concrete. The experiments investigate the bond behavior of GFRP bars with small diameters of 8 mm, 10 mm, and 12 mm in straight and end-headed configurations. Straight bars exhibited excellent bond performance and load capacity, developing most bond stress at an embedment length of 15 times the bar diameter (15<em>d</em>_<em>b</em>), resulting in the GFRP bars' rupture failure. Conversely, the end-headed bars (i.e., large heads with a length of 100 mm and small heads with a length of 50 mm) for GFRP diameters of 8 mm and 10 mm demonstrated limited efficacy. This finding suggests that end heads may not be a viable option for enhancing the load capacity in small-diameter GFRP bars. Based on the experimental results, a novel equation was proposed to predict average bond stress. In the second phase, the coefficients of the proposed equation were calibrated using data from 275 specimens (80 % of the dataset) extracted from previous studies. This equation incorporated bar diameter, embedment length, and concrete compressive strength while distinguishing between small- and large-diameter GFRP bars. Finally, it was validated against well-established models from different codes and research studies using 69 random specimens (20 % of the dataset) to demonstrate the satisfactory performance of the proposed equation. The proposed equation demonstrated superior predictive capability for load capacity, particularly for small-diameter GFRP bars, achieving the best performance with integral absolute error (IAE) and mean absolute error (MAE) values of 16.9 % and 18.4 %, respectively, compared to other models.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"479 ","pages":"Article 141512"},"PeriodicalIF":7.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891299","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of water glass-enhanced biocementation in sand: Early strength enhancement and mechanistic insights","authors":"Changrui Dong ,&nbsp;Zhen Guo ,&nbsp;Yongqiang Zhu ,&nbsp;Shengjie Rui ,&nbsp;Yujie Li","doi":"10.1016/j.conbuildmat.2025.141516","DOIUrl":"10.1016/j.conbuildmat.2025.141516","url":null,"abstract":"<div><div>Microbially induced carbonate precipitation (MICP) is considered an effective way to reinforce the ground. To improve the early strength of biocemented sand, in this paper, water glass (Na₂O-mSiO₂-nH₂O) was incorporated into MICP as an additive. A series of tube tests were employed to quantitatively investigate the impact of water glass concentration on precipitation rate and amount under varying urease activities. Experimental observations revealed that, in general, MICP was hindered by an increase in Na₂O while being promoted by SiO₂, both effects were controlled by urease activity. For SiO₂, optimal concentrations are 2 %, 3 %, and 8 % at urease activities of 25 KU/L, 15 KU/L, and 10 KU/L respectively. Then, the sand column experiments were conducted to quantify the strength enhancement. Compared with the control tests, the unconfined compression strength (UCS) was enhanced by 32.3 % after a single treatment and by 26.5 % after three treatments, respectively, while their secant modulus (<em>E</em>_<em>50</em>) rose by 37.8 %, 33.8 %, and 38.1 % following single, two, and three treatments. at a urease activity of 10KU/L. Simultaneously, based on the microscopic and compositional analyses, three distinct stages were summarized during the reaction period. In stage 1, free Ca²⁺ was precipitated and calcium silicate hydrate (C-S-H) served as potential nucleation sites. In stage 2, the intralayer calcium of C-S-H was decalcified, providing sustained calcium for MICP. In stage 3, bacteria were coated and the reaction reached stabilization. This study proposed a potential method and provided reference insights for enhancing the reinforcement effect of MICP.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"479 ","pages":"Article 141516"},"PeriodicalIF":7.4,"publicationDate":"2025-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143891304","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}