Journal of Materials in Civil Engineering

In the research reported in this paper, silica aerogel was synthesized in a cotton nonwoven mat (CNM) and then the composite was used as a sound absorber. The experimental data indicated that using aerogel as a coating on CNM significantly improved sound absorption up to 2,500 Hz. However for higher frequencies silica aerogel coating reduced sound absorption compared to neat CNM. The best sound absorption performance of the CNM coated aerogel happened between 250 and 2,500 Hz. The effects of different processing conditions were studied on the final properties of the silica aerogel and consequently on the sound absorption of the coated CNM. The pore size and surface area of the synthesized silica aerogel had no direct influence on the sound absorption properties of the composites; on the other hand, the density of the silica aerogel was the only critical factor that determined the sound absorption coefficients of the composites.

The results of axial compression tests on masonry prisms can be the basis for determining the design capacity of masonry elements since several building codes permit the compressive strength of the masonry to be that of the prisms. The cost and time required to construct and cure the prisms and the cost and time to prepare and test the prisms, in addition to the waiting time to begin construction, makes the overall prism test method expensive. Building codes, therefore, often provide an alternative to the prism test method. Typically, the alternative method establishes the compressive strength of the masonry from the compressive strength of the masonry unit and the mortar type specified by the engineer. The study presented herein is related specifically to concrete masonry, and it determined a relationship between the compressive strength of ungrouted and grouted masonry and the compressive strength of the masonry units. The relationship was established statistically using the results of a comprehensive testing program. Among the many contributions of this research is that masonry units with compressive strength of up to 70 MPa were tested. The tests results show an increase in the compressive strength of the masonry with increasing compressive strength of the units. The increase, however, was not proportional; in other words, the relationship masonry strength–unit strength decreased with increasing unit strength. The test results reported herein for the ratios of compressive strength of ungrouted masonry to compressive strength of masonry units are consistent with results reported by other researchers. Those compressive strength ratios are approximately 0.8 and 0.5 for low and high strength units, respectively. The ratios of compressive strength of grouted masonry to compressive strength of masonry units are approximately 0.7 and 0.4 for low and high strength units, respectively.

The heat generated from dark-colored asphalt pavement contributes to the rise in surface temperature and results in the formation of an environmental problem known as urban heat island. In this paper, an approach was developed to optimize the mixture design of experiment (DOE) for the mixed type of crushed waste tile aggregates in developing cool-pavement coating materials that could reduce the surface temperature of pavement. Furthermore, the mean temperature difference, $\mathrm{\Delta }T$, was determined by comparing the 16 runs of the suggested design model with the conventional asphalt model. Three types of wasted tile aggregates were used in this study: full body porcelain (FBP), monoporosa or ceramic glaze (MP), and porcelain glaze (PG). A linear model was formed as a function of mixed-tile fraction, and the ANOVA analysis showed that the special cubic term used for this model is significant. The diagnostics of the model were validated using box-cox plot and normal plot of residuals. Finally, the model was optimized to predict the optimum mixture of different types of tiles to produce the highest value of $\mathrm{\Delta }T$ by proposing two solutions from the design mix. Accordingly, the values of $\mathrm{\Delta }T$ obtained are 4.9 and 3.1°C, respectively, as per the first and second solution using 100% of FBP and MP. In conclusion, the optimum mixture DOE is reliable and can be used to optimize the composition of the proposed mixed type of tile aggregates for obtaining higher values of $\mathrm{\Delta }T$, which is necessary for developing the coating materials.

It has been reported that the application of foaming mix asphalt technology in asphalt industry helps offset the increase in energy cost, global warming, and more stringent environmental regulation concerns through decreasing the energy consumption and emissions associated with conventional hot mix asphalt production. In this study, the objective was to conduct an investigation of plant and laboratory (e.g., after reheating) compaction effects on performance properties of plant produced foamed asphalt mixtures with various recycled asphalt pavement (RAP) contents. The main properties of failure temperature and $G^{*}/\sin \delta$ of recovered binders and compaction effort, air void, indirect tensile strength (ITS), tensile strength ratio, flow, rut depth, resilient modulus, and fatigue life of plant directly compacted specimens and laboratory reheated and compacted specimens were determined in this research. The experimental design included the warm mix (foamed) asphalt mixtures from four asphalt plants in South Carolina, containing two surface mixtures. A total of over 150 specimens and 36 fatigue beams were tested in this study. The test results indicated that, as expected, the recovered binders from laboratory reheated mixtures generally have higher failure temperatures and $G^{*}/\sin \delta$ values, and lower phase angles compared with the extracted binders from plant compacted mixtures. In addition, laboratory mixtures have greater gyration numbers and higher air voids than plant mixtures. Moreover, higher ITS values, lower rut depths and resilient modulus values can be found from laboratory compacted specimens regardless of the asphalt plant site. Furthermore, fatigue life values varied from mixtures obtained from different asphalt plants.

This paper evaluates variations in the residual tensile strength of prismatic specimens made of steel fiber–reinforced high-strength concrete (SFRHSC) attributable to flexural cyclic loading. All specimens were previously subjected to a three-point static bending load test until the first flexural crack appeared. In these cases, no notched specimens were used. Next, the specimens were subjected to a preset number of three-point cyclic bending loads, without fatigue failure in any case. Finally, the specimens were submitted to a three-point static load test until failure. This test procedure shows a progressive decrease in the residual tensile strength with the number of cycles. A new definition of damage is introduced: relative variation of the tensile strength with the number of cycles. A correlation is identified between conventional damage and this new definition of damage.

This paper presents the results of an experimental and analytical study on the effect of distributed cracks (damage) on moisture transport in concrete. Specifically, the writers investigate the following: (1) how damage affects the saturated and unsaturated transport and electrical resistivity, (2) whether one-dimensional (1D) analysis based on the sharp front (SF) theory can explain the relation between the saturated and unsaturated transport in damaged concrete, and (3) which transport mechanism is more sensitive to damage. Conceptual models are developed based on damage mechanics and fluid transport to explain the experimental data. Material constants are also provided for numerical modeling of unsaturated transport in damaged concrete. The results show that damage differently affects each of the transport mechanisms, and saturated hydraulic conductivity is more sensitive to damage as compared to sorptivity and electrical resistivity. The simplified 1D analysis, based on the sharp front theory, does not adequately describe the effect of damage on unsaturated transport. The developed conceptual models can be used to qualitatively describe the effect of damage on transport properties of concrete.

An improvement of flexural strength of cement stabilized sand using polypropylene fibers designated as compacted cement-polypropylene fiber-sand (CCFS) is investigated in this research. The studied material performance of the CCFS includes postpeak behavior, toughness, and equivalent flexural strength ratio. The fiber inclusion significantly improves the postpeak flexural behavior, which is a requirement for bound pavement materials. The first peak flexural strength $f_1$ and stiffness of both compacted-cement-sand (CCS) and CCFS are essentially the same for the same cement content. For low fiber content, the fiber inclusion primarily prevents the sudden failure. The CCFS exhibits deflection-hardening behavior and the peak flexural strength ($f_p$) is higher than the first peak flexural strength ($f_1$) for medium to high fiber contents. Two modes of failure are noted: single failure plane and stress transfer–induced multiple cracks. For low to medium fiber contents, the single failure plane is observed for both deflection-softening and deflection-hardening behaviors. The high fiber contents of 2% can significantly distribute the load to different parts of the test beam; hence, multiple cracks are observed even at a large failure deflection, without a clear single failure plane. The fiber inclusion has been proven as suitable for the bound pavement CCFS material in both the failure mode and the flexural properties. These improvements are of practical significance in pavement performance and design.

Shrinkage cracking is a major issue that affects the durability of concrete structures. Plastic shrinkage of cementitious materials can lead to cracking within 24 h of casting and sets the stage for premature deterioration. Although test techniques exist that can be used to evaluate the plastic shrinkage cracking potential of cement-based materials, mathematical models that predict the influence of various parameters such as water-cement ratio (w/c), aggregate to cement ratio, and the effect of fibers on cracking are not available. This paper presents a model that can be used to predict plastic shrinkage cracking in cement-based materials. The model is developed by using factorial design and utilizes representative data generated with a technique developed by the authors. The effectiveness and limitations of the model in predicting crack areas and width are discussed. The effect of variables such as w/c, sand/cement ratio, fiber dosage, and the interaction between these variables is also presented in this paper.

Corrosion is one of the most critical problems that impair the durability of RC structures. Both carbonation-induced and chloride-induced corrosion widely prevail in civil infrastructure around the globe. Expansive products are formed due to corrosion at the interface between concrete and reinforcing bar (rebar). The cracking and spalling in concrete due to expanding corrosion products and the reduction in the cross-sectional area of rebar jeopardize the safety and serviceability of RC structures. From an outsider perspective, this literature review summarizes the state of the art on the mechanisms of the two types of corrosion, mechanical degradation in RC structures as a result of these mechanisms, the analytical methods to predict the basic parameters most related to corrosion, and the available laboratory and field corrosion measurement techniques.

Prefabricated bridge elements and systems (PBES) construction relies on field-cast, grout-type materials to complete the connections between precast concrete elements. This PBES construction facilitates and accelerates bridge construction (ABC), increases safety, and minimizes the inconveniences to the traveling public while delivering a superior product. Although prefabricated concrete components are produced in a controlled environment, field-cast grouts have at times shown serviceability issues mainly associated with dimensional stability. This paper assesses the dimensional stability (primarily shrinkage) of a total of seven prebagged grouts currently used in the construction industry. Their shrinkage performance is compared to that of an ultrahigh-performance concrete. The feasibility of the test methods used for evaluating the dimensional stability of nonshrink grouts is also discussed. Although many grouts are referred to as nonshrink materials, the results show shrinkage, especially in drying conditions. The use of the internal curing technology as an emerging solution for mitigating shrinkage in grout-type materials is also discussed. The results obtained in two of the cement-based grouts, including internal curing, show a reduction of both autogenous and drying shrinkage. Based on the results obtained, recommendations are given to end-users to provide guidance in selecting an appropriate grout-type material.

EN 934-2 “Admixtures for concrete, mortar and grout Concrete admixtures. Definitions, requirements, conformity, marking and labelling” requires that any increase in the air content shall not be more than 2% by volume over that obtained from the reference mix, and most types of superplasticizers (SPs) easily meet this requirement. Some types may even reduce the level of air, and this can result in a less cohesive mix, which may be more prone to bleed and segregation or may leave the mix feeling harsh and difficult to handle. Unfortunately, some types of superplasticizers increase the level of air. Too high a volume of air has been overcome using an antifoaming agent. The influence of new-generation type superplasticizer and antifoaming admixture (AFA) on the air content and workability of high performance self-compacting concrete (HPSCC) is analyzed in this paper. The purpose of this study was to examine the influence of the admixture type on pore size distribution, compressive strength and frost resistance of HPSCC at constant water to cement ratio, type and volume of aggregate, and volume of cement paste. The parameters of the open pores and air voids of hardened HPSCC are also investigated. The results presented in this paper show that admixtures significantly influence the investigated properties of HPSCC.

Asphalts aged in laboratory conditions have been extensively studied, but those aged in hot-mixed asphalt (HMA) mixtures in the field receive less attention. Particularly missing are the aging characteristics of asphalts in long-life HMA pavements. In this study, the rheological and chemical properties of asphalts that were aged in HMA pavements for 7 and 36 years were examined, including the variations of these properties with pavement depth and their interrelationships. The analysis results suggest that (1) severe asphalt binder aging occurred at the deepest pavement layer, (2) material type and pavement depth affect aging rate, (3) asphalt binder from the deepest layer showed a loss of saturates, (4) binders’ two important rheological properties are well related to asphaltenes content and ketone formation, and (5) age hardening apparently is affected more by the increase of dispersion volume and size than by the viscosity of the suspension medium. These findings not only prove that asphalt binder aging is a legitimate concern for the durability of long-life HMA pavements, but also lay a foundation for future research to tackle this issue.

Natural pozzolans are defined as either raw (volcanic material, limestone) or calcined natural materials (burnt shale, calcined kaolinite) with pozzolanic properties. Historically, they are among the oldest materials that have been used in combination with lime for construction purposes. For example, Santorin earth is a natural pozzolan from a volcanic eruption around 1500 BCE on an island of the same name in Greece. Over the last decades, research into cement matrices has been changing direction, owing to deeper environmental concerns over the impact of the cement industry and its consequences for climate change. Global environmental policies are increasingly strict, prioritizing the re-use rather than the disposal of industrial wastes. In this context, one of the biggest challenges is the search for strategies that promote the industrial rotation of high volumes of wastes in their productive cycles. The main purpose of this research is to widen the existing knowledge base on the behavior of new mineral pozzolans of high added value in the cement sector, lending special attention to paper sludge wastes generated in the process of paper manufacture, in which recycled paper is used as a raw material. The results to date show that, once thermally activated (in the range of 650–700°C), paper sludge turns out to be an alternative source of recycled metakaolin. This product is characterized by its high pozzolanic activity and improved performance with regard to the benefits of certain binary cements. The possibility of incorporating this industrial waste in cements along with other already standard pozzolans focuses, as mentioned, on the notable increase in the production of these types of cements. This is due, at present, to the extensive constructive applications for type-II cements (single additive) and to their lower economic and energetic costs that also makes them more suitable in times of economic crisis. In the present paper, the influence that pozzolan blends (activated paper sludge and fly ash) have on the reaction kinetics of ternary blended cements (6 and 21% of replacement) is evaluated, paying special attention to the identification and evolution of hydrated phases with increasing reaction times. The results obtained represent a pioneering research line at a global level and represent a starting point for future investigations because in the case of using paper sludge, release of ${\mathrm{CO}}_2$ from organic matter is very low and is listed as zero release.

The rheological properties of silly putty (SP) and its application as a shock transmission unit (STU) were studied in the paper. By using a parallel-plate rheometer, the frequency sweep at different temperature was carried out to investigate the rheological properties of SP. For all test temperatures, the complex viscosity of SP shows shear thinning, but the $G^{\prime }$-curve shows a moderate slope and a gradual transition to the constant plateau value. And once the angular frequency exceeds a critical value, the storage modulus will exceed the loss modulus under the condition of all temperatures. Two prototypes of STU were fabricated with SP and their mechanical performances were experimentally evaluated. The results of the slow movement test and the simulated dynamic test show that the STU can provide a free motion under slowly applied loads and a rigid link under impact loads.

Cross-laminated timber (CLT) is a novel wood building material suitable for floor, roof, and wall assemblies in low- and mid-rise construction as an alternative to concrete and steel. CLTs are considered to provide good seismic resistance, fast erection times, carbon sequestration, and a significant reduction in greenhouse gas emissions over other construction materials. Southern pine is an abundant forest resource; yet it has not been commercially used for CLT manufacturing. The purpose of this paper was to measure the bending and shear properties of CLT material fabricated using southern pine lumber compared to product standards. Bending strength, bending stiffness, shear strength, resistance to shear by compression loading strength, and resistance to delamination were measured according to product standards, and test results were compared with values given in the standards. Bending tests were conducted on jointed beams due to test length requirements. Bending strength, bending stiffness, and wood failure in resistance to shear by compression loading tests exceeded the published values for the published values, while resistance to delamination did not meet the established criteria. The resistance to delamination results may have been affected by the uncontrolled moisture content of the lumber during fabrication of the CLTs. The application of glued laminated lumber standards to CLT products requires clarification in the orientation of loading directions for the resistance to shear by a compression loading test and the measurement of all four sides of the resistance to delamination specimens. Increased scrutiny of moisture content quality control is highly encouraged for the production of CLTs.

Strengthening and retrofitting structural members using carbon fiber reinforced polymer (CFRP) materials has gained wide acceptance in the civil engineering community because of their superior mechanical properties, light weight, corrosion resistance, and ease of use. Numerous structural reinforced concrete (RC) members have been strengthened with externally-bonded CFRP plates using epoxy adhesives that produce an increase in their load-carrying capacities. However, there are some uncertainties regarding the durability of the bond between the concrete and FRP interfaces when subjected to severe environmental exposure. Most strengthening applications are exposed to outdoor conditions and hence durability under aggressive environments must be considered. This is the subject of this investigation. Several CFRP-concrete prisms have been subjected to several sets of environmental exposure conditions and preloaded with 3 and 5 kN of sustained loading, amounting to approximately 15 and 25% of ultimate load, respectively. Site exposure conditions were an actual marine environment and a seawater splash zone, including direct exposure to sunlight with the associated Ultra Violet (UV). Both exposures were conducted in a well-controlled atmosphere that lasted for more than 150 days (3,600 h). The experimental program consisted of 27 specimens divided among the two exposures and some laboratory control specimens as benchmarks. The specimens were subjected to sustained loading during the whole course of the exposure. The change in ultimate bond characteristics between the externally-applied CFRP and the concrete because load and exposure conditions were used as measures of durability and performance effects. Single-lap shear tests were conducted on all specimens after exposure to failure of the specimens. It was observed that the specimens exposed to the sun and saline environments experienced an increase in both the bond strength and attained peak loads because exposure of the adhesive to elevated temperature increased the bond because of greater polymer crosslinking, thus creating complex interactions in the polymer matrix. The data obtained from this experimental investigation will add to the sound scientific data demanded by the ACI 440.2R-08 design guidelines.

In the Aveiro district, Portugal, adobe was a construction material extensively used until the middle of the twentieth century. Presently, many adobe constructions are still in use, presenting important cultural, social, and architectural value. Many of these constructions, however, are in a poor state of conservation, displaying severe structural anomalies. This negligence is in part due to a lack of knowledge concerning the mechanical behavior and properties of adobe masonry. The purpose of this paper is to contribute to this knowledge. Ten full-scale adobe wall panels were constructed in the laboratory with adobes collected from an existing construction and with mortar formulated with the composition traditionally used. Five wall panels were tested in simple compression and five wall panels in diagonal compression. From these tests it was possible to determine and evaluate the stress-strain relationships, strength, deformation, stiffness, and damage pattern of the adobe masonry walls. This knowledge can support the adequate rehabilitation and retrofitting of existing buildings, the calibration of numerical models, and even the design of new adobe constructions.

Although foamed warm mix asphalt (WMA) offers many potential benefits, there are some performance concerns. Researchers are making efforts to study the usage of different additives as modifiers to meet standard specifications of asphalt mixes for paving applications; however, selection of an appropriate modifier is extremely important to better performing asphalt. In recent years, there has been a dramatic interest in research, technology, and production of nanoparticles (nanomaterials). The current study was conducted with the objective of addressing the potential benefits of using nanosized hydrated lime (NHL) compared with regular-sized hydrated lime (RHL) as a modifier to the WMA produced using an additive. This paper documents the findings of the effect of NHL and RHL on the asphalt binder rheology and provides an insight into their effect on the free energy of adhesion of the asphalt binder–aggregate system. The rheology of asphalt binder was investigated based on the dynamic shear rheometer (DSR) test, whereas the free energy of adhesion was quantified based on the surface free energy (SFE) measurements of the asphalt binders and aggregate. Rheology results showed that the addition of NHL in smaller amounts can provide improved characteristics as compared with RHL. In concurrence with the rheology results, the free energy of adhesion showed that the NHL is more competitive compared with the RHL. Foaming the asphalt binder adversely affects the asphalt binder-to-aggregate adhesion.

Previous studies have clearly shown that flat slabs made of ultrahigh-performance concrete (UHPC) have considerably higher punching shear strength than their counterparts made of conventional concrete. However, it may not be economically feasible to construct an entire slab out of UHPC. As such, the objective of the research reported in this paper was to determine the optimal use of UHPC within the critical punching shear area, while the remainder of the slab is made of normal concrete. Ten flat slab specimens with two different steel reinforcement ratios and three different areas (or depths) of UHPC were tested under a concentric load to study the effect of UHPC on punching shear capacity of flat slabs. Test results showed that full-depth application of UHPC within the area enclosed by a perimeter located at a distance equal to the slab thickness from the column face could enhance punching shear capacity of the slab by 70%. This configuration was deemed to be the optimal application of UHPC in flat slabs. On the other hand, half-depth application of UHPC does not significantly improve shear capacity of flat slabs. The research reported in this paper also questioned the applicability of two available punching shear models for flat slabs made fully or partially out of reinforced UHPC.

The results of the laboratory investigation performed on clay beds reinforced with natural (bamboo) and commercial (geosynthetics) reinforcement materials are reported in this paper. To use bamboo effectively, three-dimensional cells (similar to geocells) and two-dimensional grids (similar to geogrids) are formed using bamboo (termed bamboo cells and bamboo grids, respectively). The performance of clay beds reinforced with bamboo cells and bamboo grids is compared with that of clay beds reinforced with geocells and geogrids. The bearing capacity of the clay bed increased by six times when a combination of geocell and geogrid was used. The ultimate bearing capacity of the clay bed reinforced with bamboo cell and bamboo grid was found to be 1.3 times more than that of clay bed reinforced with geocell and geogrid. In addition, substantial reduction in the footing settlement and the surface deformation was observed. The tensile strength and surface roughness of bamboo were found to be nine times and three times, respectively, higher than geocell materials. The bamboo was treated chemically to increase its durability. Although the performance of bamboo was reduced by 15–20% after the chemical treatment, its performance was better than its commercial counterparts.

This paper aims to develop empirical equations predicting one-day, three-day, and seven-day heat of hydration of portland cement at 23°C and water to cement ratio of 0.5. Isothermal conduction calorimetry was implemented to measure the heat of hydration of portland cements for up to seven days. X-ray diffraction was used to study the mineralogy and also for quantification of phase composition of portland cements. Particle size distribution of cements was measured using a laser scattering particle size analyzer. Blaine fineness of cements was measured using a Blaine permeability apparatus in accordance with the standard test methods for the fineness of hydraulic cement by air-permeability apparatus procedure. The results indicate that the one-day, three-day, and seven-day heat of hydration of a specific portland cement ground to different finenesses is changing linearly with the cement mean particle size. This research shows that the mean particle size is a suitable measure of cement fineness to correlate with major phases of portland cement (${\mathrm{C}}_3\mathrm{S}$, ${\mathrm{C}}_3\mathrm{A}$, ${\mathrm{C}}_2\mathrm{S}$, ${\mathrm{C}}_4\mathrm{AF}$) in developing equations predicting the heat of hydration of cements at one, three, and seven days.

Tire derived aggregate (TDA) is a recycled fill material produced by cutting scrap tires into pieces ranging in size from 12 to 305 mm. For the last two decades, TDA has been successfully used in various projects such as embankments, bridge abutments, subgrade insulation for roads, vibration mitigation for rail lines, and landfill daily cover. The material properties of TDA are necessary for the planning and design of such projects; however, there is limited information available, especially for large-size TDA (maximum particle size $\ge 75\mathrm{mm}$). Large-size TDA is typically used as lightweight fill material for embankments, foundations, and retaining walls. In this paper, the material properties of large-size TDA, as collected from published sources and recently completed material tests, are presented and discussed. These properties include unit weight, shear strength, compressibility, and lateral earth pressure coefficient. In addition, several civil engineering projects are discussed and compared to highlight the use of TDA in state-of-the-art applications.

The induction healing effects have been experimentally investigated through the cyclic beam fracture and healing testing of asphalt mixture samples with conductive steel wool fibers. This study aims to investigate the healing level of asphalt mixture through the integrated work of laboratory experiment and numerical simulation. Nine single-edge notched beam (SENB) samples containing steel fibers were prepared and used for the laboratory fracture test. Afterward, three divided groups of fractured samples were subjected to the induction healing at controlled temperatures of 60°C, 80°C, and 100°C, respectively. Then the reloading fracture test was conducted with three groups of samples to measure the fracture strength recovery ratio (FSRR) after induction-healing process, which is defined as the ratio of the recovered peak load to the original peak load. The discrete element method (DEM) was utilized to simulate the beam fracture process. A fracture toughness-based bond healing model was used to simulate the microcrack healing effect. The reloading experimental results (after the first healing process) showed that the average FSRR values of sample groups healed at 60°C, 80°C, and 100°C were 0.825, 0.965, and 0.900, respectively. The simulated fracture test results using DEM were in good agreement with the experimental results with respect of the peak load and the slope of load increase. A highly linear correlation between the FSRR and the bond healing level were found based on the numerical simulation and the experimental results. Based on the correlation, the actual bond healing levels of the samples healed at 60°C, 80°C, and 100°C were obtained as 76.2%, 92.1%, and 84.7%, respectively. This study provides a microstructural DEM fracture-healing model to predict the healing level of asphalt mixture by comparing it with experimental data.

Depleting timber resources has generated interest in bamboo, a traditional sustainable building material of the tropics. However, dearth of strength data has been a major hindrance in its engineered application. The present paper reports experimentally verified compressive and cleavage strengths of an Indian bamboo species that is considered suitable for structural applications. The investigated compressive strength is well comparable with that of equivalent timber. The paper reports lesser strength of split bamboo specimens than round ones, which contradicts the provisions of some codes. The paper also observes that compressive strength of bamboo generally increases along its culm length, gradually from bottom to top. The paper further identifies a factor, which when multiplied by the density of a given specimen, yields corresponding permissible compressive strength. Low values of coefficients of variation and skewness of the experimental data indicate its reliability. This paper may be considered as a step towards engineered application of bamboo.

The bonding behaviors of shale ceramsite lightweight aggregate concrete (SCLC) and normal weight concrete (NC) were experimentally investigated, with SCLC and NC manufactured by incorporating shale ceramsite aggregate and gravel aggregates, respectively. Pullout tests of six-group specimens were conducted (102 pullout specimens in total) to research the load-slip relationship, failure modes, and bond strength of SCLC. Test results indicated that the load-slip relationship and failure modes are dependent on the concrete strength, embedment length, and bar diameter for SCLC. No obvious difference of the peak load occurs for SCLC and NC under the condition of the equivalent strength, but the peak slip for SCLC increases 15–25% compared with NC. The bond strength of SCLC depends on many factors including concrete strength, concrete cover, bar diameter, embedment length, and stirrup ratio.

This paper presents the results of a testing plan designed to evaluate the effects of macrosynthetic fibers on pervious concrete material properties and durability. The effects of two lengths of fibers (38 and 56 mm) were investigated at three dosage rates (1.5, 3.0, and $4.5\mathrm{kg}/{\mathrm{m}}^3$) in a single mixture. The unit weight and void content of all samples were controlled to allow determination of the effects caused directly by the fibers. Samples were tested for strength and durability properties. The results indicate that fibers in general reduced permeability and the infiltration rate, while reducing surface abrasion and improving freeze-thaw durability.