Point Load Test Research Articles

Punching Shear in Steel Fibre Reinforced Concrete Slabs Without Traditional Reinforcement

The punching shear capacity of steel fibre reinforced concrete (SFRC) slabs without traditional steel bar reinforcement was investigated by conducting central point-load tests on twelve square slabs. The test parameters covered fibres with different multi-hook ends, concrete compressive strength, reinforcing index and slab thickness. The statistical performance of two existing models for the prediction of punching shear capacity of SFRC slabs without traditional reinforcement was examined. The load carrying capacity of these slabs were also assessed using the yield line theory. It is noted that the slabs failed primarily in flexure and the yield line theory predicted the load carrying capacities of the slabs most accurately. The reason for a flexural failure in SFRC slabs without steel bars is attributed to the lesser energy required in the propagation of an existing flexural cracks than in the creation of a new circumferential cracks around the column face.

Effects of weathering on characteristics of rocks in a subtropical climate: weathering morphology, in situ, laboratory and mineralogical characterization

This paper presents the results of a comprehensive study on the morphology of weathering profiles developed on metamorphic and sedimentary rocks under subtropical climate, focusing on its influence on geotechnical parameters of weathering materials. Several cut and natural slopes were selected for more detailed descriptions of their physical, mineralogic, geologic, structural and geotechnical parameters, focusing on weathered rock materials, including characteristics of matrix (e.g., fabric, mineralogy and degree of weathering) and rock mass (e.g., rock:soil ratio, discontinuity characteristics, JRC—joint roughness coefficient, and JCS—joint compressive strength). Samples from the upper portions of the profiles and down into the transition zone between rock and soil were collected to determine their physical and geotechnical parameters, to prepare and describe thin sections and to perform X-ray diffraction (XRD) analyses and point load tests. Results indicate that weathering profiles are thin, contacts between material layers are sharp and there is a strong structural control on weathering, mainly by stress-relief joints. Soil-like material is present only in portions of the rock mass near the ground surface or along structural discontinuities (foliation and fractures). Thin-section description can provide important indexes and information that can be related to chemical and physical weathering of those rocks and so be used to differentiate materials present along profiles. Also, physical parameters have proved to be useful for the distinction of different weathered materials. Finally, XRD and thin-section description have allowed the identification of important mineralogical changes due to weathering.

Impacts of karst phenomena on engineering properties of limestone foundation bed, Ar Riyadh, Saudi Arabia

Evaluation of mechanical and petrophysical properties of the karst limestone became essential to avoid future risks in the construction of new urban cities built on limestones. Therefore, this study aims to evaluate the impact of karsts phenomena on engineering properties of limestone foundation bed at Ar Riyadh in Saudi Arabia. Three hundred core plugs were obtained by rotary drilling at depths ranging from the ground surface to 20 m collected from 24 boreholes in two sites: (1) karst limestone (KL) at Al Aziziyah district and (2) massive hard limestone (HL) at Hittin district in Ar Riyadh city, Saudi Arabia. Petrographic, SEM, EDX, and XRD analyses are used to identify the mineralogical composition and microstructures of limestone samples. The petrophysical properties included the ovendry density, P-wave, and porosity where the mechanical properties covered the uniaxial compressive strength (UCS), point load strength index (PLI), and rock quality designation (RQD) for the karst and hard limestone samples. KL is characterized by 17.11% total porosity, 14.71% water absorption, 32.1 MPa UCS, 1.70 g/cm3 ovendry density (γ dry), 51% weathered RQD, 5.49 MPa medium shear strength, and low modulus of deformation of the plate loading test. HL showed 11.63% total porosity, 9.45% water absorption 43.1 MPa UCS, 2.50 g/cm3 ovendry density (γ dry), 78% hard to fresh rock affinity RQD, and 9.93 MPa high strength and high modulus of deformation of the plate loading test. For the water absorption (%), KL at Al Aziziyah district showed a range of 12.85–17.80% averaged 14.71%. HL at Hittin district varied between 7.04 and 11.29% with an average of 9.45%. KL proved to be dense with ovendry density (γ dry) averaged at 1.70 g/cm3 while HL showed very dense affinity of 2.50 g/cm3. KL clarified a UCS range from 22.5 to 40.1 MPa and an average of 32.1 MPa while HL showed a range from 35.4 t o 48.1 MPa with an average of 43.1 MPa. KL is moderately weathered with RQD average of 51% while HL showed a hard to fresh rock affinity of 78%. Point load test clarified a medium shear strength with 5.49 MPa for KL and high strength of 9.93 MPa for HL. Plate loading tests indicated low and high modulus of deformation for KL and HL, respectively. Results of petrographical analyses and XED of limestone samples showed that the strength parameters of samples mostly composed of micrite (mudstone/wackestone) and dolomite in hard limestone of Hittin district. In Al Aziziyah district (KL), the samples mostly consist of foraminifera and high amount of calcite as in karst limestone (wackestone/packstone). Rock mechanical tests with combination of fabric analyses have shown that strength parameters depend not only on the amount of karst but also on the amount of allochem. Major geomechanical differences between the two types of limestone provide the proper base for prioritizing areas to alleviate future risks and sustainable urban planning for decision makers. The karstic limestone, therefore, is considered as an acceptable foundation bed for light engineering structures. However, for heavy structures and buildings, improving the foundation bed strength by grouting, cement injection, and mat foundations is necessary to avoid future failure risks.

Utilizing regression models to find functions for determining ripping production based on laboratory tests

The selection of suitable overburden loosening method has a crucial importance in several applications of geotechnical engineering. Factors such as rock properties and environmental constrains play a significant role in the selection of the needed equipment for overburden loosening. This paper presents several new models/equations for prediction of ripping production (Q) using rock material properties. To this end, three sites in Malaysia were selected and a total of 52 direct ripping tests were conducted in Johor state on sandstone and shale rock types. In addition, using the collected block samples, point load test, Brazilian test, slake-durability test, p-wave velocity test and uniaxial compressive strength test were also carried out in the laboratory. Numerous equations have been proposed to predict Q considering simple regression, linear multiple regression (LMR), and non-linear multiple regression (NLMR) models. Simple regression analysis indicated that the relationships between rock material properties and Q were meaningful and acceptable. Furthermore, both LMR and NLMR equations indicated similar performance capacity in predicting Q. Nevertheless; the use of NLMR equations resulted in prediction performance with higher accuracy in estimating Q compared to LMR equations.

Simple empirical formula to estimate the main geomechanical parameters of preplaced aggregate concrete and conventional concrete

Preplaced aggregate concrete (PAC) or two-stage concrete is a specific type of concrete successfully employed in many projects including underwater concrete structures, massive concrete structures, structures made of reinforced concrete, and improvement of concrete structures. PAC is significantly different than the conventional concrete. In this type of concrete, aggregates are initially poured into the mold, the voids between which are then filled with sand and cement mortar. Additionally, the concrete provides grain-to-grain contact for the aggregates. Since use of PAC in construction projects is growing, this paper is aimed to present experimental relations for estimation of geomechanical parameters of PAC and conventional concrete. To this end, 144 and 72 specimens made of PAC and conventional concrete, respectively, were prepared, on which uniaxial compression test, Brazilian tensile test, and point load test were conducted. Then, the resulting data from the experiments were classified into two categories, namely the regression and the test data. Moreover, experimental relations were obtained between the compressive strength, tensile strength, Young’s modulus, corrected point load index, and Poisson’s ratio for both conventional concrete and PAC, and their validity were then investigated. The results indicated that the obtained relations could be used to estimate the geomechanical properties of PAC and conventional concrete with acceptable accuracy.

The estimation of uniaxial compressive strength conversion factor of trona and interbeds from point load tests and numerical modeling

The point load (PL) test is generally used for estimation of uniaxial compressive strength (UCS) of rocks because of its economic advantages and simplicity in testing. If the PL index of a specimen is known, the UCS can be estimated using conversion factors. Several conversion factors have been proposed by various researchers and they are dependent upon the rock type. In the literature, conversion factors on different sedimentary, igneous and metamorphic rocks can be found, but no study exists on trona. In this study, laboratory UCS and field PL tests were carried out on trona and interbeds of volcano-sedimentary rocks. Based on these tests, PL to UCS conversion factors of trona and interbeds are proposed. The tests were modeled numerically using a distinct element method (DEM) software, particle flow code (PFC), in an attempt to guide researchers having various types of modeling problems (excavation, cavern design, hydraulic fracturing, etc.) of the abovementioned rock types. Average PFC parallel bond contact model micro properties for the trona and interbeds were determined within this study so that future researchers can use them to avoid the rigorous PFC calibration procedure. It was observed that PFC overestimates the tensile strength of the rocks by a factor that ranges from 22 to 106.

A Study on Rock Mass Classifications and Tunnel Support Systems in Unconsolidated Sedimentary Rock

This paper presents new valuable field data and a comprehensive approach to the determination of the rock mass classification and tunnel support systems for tunnels in unconsolidated sedimentary rocks as a special soil condition. The main objective of this study is to investigate and present the characteristics of the unconsolidated sedimentary rock by using the point load tests and slake durability tests. In addition, the appropriate rock mass classification and tunnel support system for the unconsolidated sedimentary rock tunnel are proposed, based on the results of experimental tests. The proposed rock mass classification and tunnel support system are validated through comparison against results from measuring the convergence of a tunnel under the construction. The proposed tunnel support system is appropriate for the unconsolidated sedimentary rocks, since the convergence factors, such as the maximum displacement and velocity of displacement, satisfy the criteria.

Weathering of metapelites from the Quadrilátero Ferrífero mineral province, southeastern Brazil

Low-grade metamorphic rocks are known for their low mechanical strength and high weatherability. In the Quadrilatero Ferrifero, an important mineral province located in southeastern Brazil, this set of features results in frequent issues with mining and road slope instability, mainly associated with phyllites. Despite the significant iron ore production that occurs in this province, little is known about the geotechnical properties of the materials constituting the weathering front. Here, we report work aimed at investigating the changes in the basic properties of phyllites at four weathering grades. The methodology used included the field classification and mapping of four weathering grades in order to assess their spatial distribution on a road slope, as well as sampling for geological characterization by petrography and X-ray diffraction (XRD). In addition, the authors performed a physical characterization of all weathering grades, including index properties, mercury porosimetry, and strength data obtained with a Schmidt hammer both in the field and in the laboratory as well as using the point load test (PLT). Results showed the relevance of structural features such as discontinuities and metamorphic foliation observed in the weathering morphology in situ, with different weathering intensities occurring along the slope. Changes in the porosity and pore size distribution in the weathering front were nonlinear, as were resistance variations. The difficulty involved in performing the macroscopic identification of weathering grades due to the very fine texture of the rock as well as microstructural heterogeneities are likely causes of the observed variability in phyllite properties. This fundamental knowledge may aid the prediction of short-term and long-term scenarios for slope stability based on rock weatherability.

Estimation of Elastic Modulus of Rock Using Modified Point-Load Test

Abstract An alternative method for determining the elastic modulus of sandstone using a point-load test (PLT) is presented. The PLT was modified to obtain the relationship curve between the test load and the displacement of the load platen. A model is modified to establish the relationship between the elastic modulus and the slope of the linear portion of the curve. Several types of sandstone specimens with different sizes were used in the tests conducted to examine the validity of the proposed method. The results show that the proposed method in the present study is in good agreement with the standard test method for the elastic modulus. In addition, the adaptability of the method for irregular rock specimen was also discussed.

Predicting the Building Stone Cutting Rate Based on Rock Properties and Device Pullback Amperage in Quarries Using M5P Model Tree

One of the key parameters that affect the selection of equipment and the cost estimation of dimension stone quarries is the rock cutting rate or production rate. In this study, the M5P tree algorithm is used to determine the relationship between the hard rock sawability and its factors especially the physical and mechanical characteristics of rock. To achieve the research goal, a variety of eleven types of hard dimension stone were selected and nine major physical and mechanical characteristics of rock including uniaxial compressive strength, Young’s modulus, Brazilian tensile strength, equivalent quarts content, grain size, Mohs hardness, point load test, density and P-wave velocity of these samples were evaluated. The cutting rate of diamond wire for all of the Workpiece was measured at different pullback amperage with a fully instrumented cutting platform in laboratory. All operational parameters of cutting process were entirely controlled. Thus, a database containing 99 datasets was provided and it has been used for analyses. The obtained results from the pruned and unpruned tree models showed a significant relationship between cutting rate and its factors. In the end, the results of M5P tree method were compared with statistical analyses (i.e., linear and nonlinear regression). The coefficient of determination be equal with 0.92, 0.86, 0.77 and 0.63 for unpruned tree, pruned tree, linear and nonlinear regression method respectively. This comparison showed that the both method of M5P tree technique have a better performance in predicting the cutting rate rather than the statistical regression methods.

Prediction of mechanical behaviour from mineralogical composition of Sakesar limestone, Central Salt Range, Pakistan

Petrographic and mechanical properties of early Eocene Sakesar limestone have been investigated to establish the relationship between these parameters. Microscopic study revealed the presence of micrite (51.38%), sparite (12.90%), dolomite (12.95%), and allochems (20.88%) in the limestone samples. The strength parameters such as unconfined compressive strength (UCS), point load test (PLT), and Schmidt rebound hammer values (R n ) were determined in the rock mechanics laboratory. Regression analyses were carried out to establish correlation between limestone constituents and the strength parameters. The UCS and other mechanical properties showed moderate inverse relationship with sparite and allochems, whereas micrite and dolomite indicate a positive correlation with UCS. To get significant correlations for cumulative micrite + dolomite and sparite + allochems, percentages and strength parameters were arranged in decreasing order. The fixed threshold for the cumulative values of micrite and dolomite were ≥80, 70–80, 60–70, 50–60 and <50%. Percentage of these constituents and the corresponding mechanical parameters were arranged on these thresholds. The cumulative modal constituents of the limestone were plotted against the mechanical parameters. Correlation among these values allowed developing equations for prediction of mechanical behaviour from mineralogical composition of Sakesar Limestone with more than 95% accuracy.

The Characterization of Flysch Rock in Albania with Field and Laboratory Testing

Albania has approximately 2/3 of its surface of flysch rocks. In areas where these rocks are present, are built several important objects, such as roads or hydroelectric power plants. These rocks are problematic for the slopes stability. The authors of this paper, to provide technical solutions for slopes stability of roads and the parts of hydropower objects (dam power house), have performed a significant amount of field and laboratory tests. On site testing included: quantitative description of discontinuities in rock masses; orientation, spacing, persistence, roughness, edge strength, aperture, filling, seepage, number of sets, block size and drill coring. Laboratory testing included: water content, porosity, density, absorption, swelling pressure, uniaxial compressive strength, point load test (PLT), Brazilian tensile strength (BTS) and direct shear test (DSH). A.L.T.E.A. & Geostudio 2000 l.t.d has been conducting 800 m drilling to determine the quality of flysch rocks. More than 100 samples, of flysch rocks (mudstone and sandstone), from the formations that form the Devolli and Osumi valleys, were taken and tested. The geotechnical calculations for the stability conditions of the slopes are made based on the data, obtained by the test results. The slopes of Devolli and Osumi valleys are monitored by means of inclinometers, which indicate any movement that has taken place, through time and weather conditions’ changes.

Correlation Between P-wave Velocity and Strength Index for Shale to Predict Uniaxial Compressive Strength Value

Seismic refraction survey is a non destructive method used in site investigation to identify the seismic velocity subsurface strata. Although it is widely known, the reliability of the result is still doubtable for some reason as well as due to an engineer’s ignorant, which insist on using conventional method rather than new advanced method causing the lack of usage in geophysical method for testing. This study aims to produce a correlation between P-wave velocity value and point load strength index value for shale. Both field and laboratory tests were carried out. In order to obtain the P-wave value, seismic refraction method was conducted as a field test at Precint 4, Putrajaya, Malaysia to achieve the Pwave velocity value of the shale bed. Ten samples of shale were collected from the field and laboratory tests were conducted. The tests are divided into three sections, namely non-destructive laboratory test, physical properties test and mechanical properties test. Ultrasonic Velocity Test via PUNDIT test was conducted as non-destructive laboratory test to acknowledge the P-wave velocity value in laboratory. Both field and laboratory P-wave velocity value were then compared and the result delivers are reliable due to it is within the range. For physical properties test, the rock density and porosity were acknowledged. Meanwhile, Point Load Test was conducted as mechanical properties. Correlation for both Pwave velocity value and point load strength value were achieved via producing an empirical relationship as the end result. Prediction of uniaxial compressive strength (UCS) value was made via converting the point load strength value to UCS value using a correlation. By acknowledging this empirical relationship, it shows that geophysical methods are able to produce a reliable result. Hence more and widely used of geophysical method will be profound in the future.

Precast tunnel segments reinforced by macro-synthetic fibers

The use of fiber reinforced concrete in tunnel linings, with or without conventional rebars, has increased in the two last decades, especially with regard to precast tunnel segmental linings. In addition, there is a general growing interest in the scientific community on macro-synthetic fibers for use in underground structures.Within this framework, the present study investigates the possibility of using polypropylene (PP) fiber reinforcement in hydraulic precast tunnel segments by means of an experimental program on six full-scale segments of Monte Lirio hydraulic tunnel (Panama). Three different reinforcement solutions were studied both under flexure and point load test: typical conventional reinforcement generally adopted in practice (reference samples, RC); PP fibers only (PFRC specimens); combination of PP fibers and conventional reinforcement (hybrid solution, RC+PFRC segments). Based on the loading configurations considered, experimental results showed that PP fibers (with or without reinforcing bars, depending on loading conditions) represent an efficient reinforcement for hydraulic precast tunnel segments. PP fibers can be used as flexural, splitting and minimum shear reinforcement, while concerning the spalling reinforcement, only PP fiber reinforcement could be used even if the combination with conventional reinforcement (hybrid solution) guarantees a better control of spalling cracks for high load levels.

Failure and stress analysis of through-aluminum-nitride-via substrates during thermal reliability tests for high power LED applications

The objective of this study is to evaluate the reliability of through-aluminum-nitride-via (TAV) substrate by comparing those experimental results with the finite element simulation associated with measurements of aluminum nitride (AlN) strength and the thermal deformation of Cu/AlN bi-material plate. Two reliability tests for high-power LED (Light emitting diode) applications are used in this study: one is a thermal shock test from −40°C to 125°C, the other is a pressure cook test. Also, the strength of AlN material is measured by using three-point bending test and point load test. The reliability results show that TAV substrates with thicker Cu films have delamination and cracks after the thermal shock test, but there are no failure being found after the pressure cook test. The determined strengths of AlN material are 350MPa and 650MPa from three-point bending test and point load test, respectively. The measurement of thermal deformation shows that the bi-material plate has residual-stress change after the solder reflow process, also indicating that a linear finite element model with the stress-free temperature at 80°C can reasonably represent the stress state of the thermal shock test from −40°C to 125°C without considering Cu nonlinear effect. The further results of the finite element simulation associated with strength data of AlN material have successfully described those of the reliability test.

Study on Shear Behavior of Concrete-polymer Cement Mortar at Elevated Temperature

In this experimental and analytical work, interfacial shear strengths were evaluated at material and member level. Bi-surface shear strength was performed at material level and three-point bending test was conducted at member level. Beams were strengthened by adding steel reinforcement at soffit level and covered by spraying polymer cement mortar (PCM). After curing, strengthened RC beams were exposed to 60 ℃ for 24 hours and tested in three point loading test. Flexural capacity, load deflection relationship and failure modes were observed and compared with the strengthened beams tested at 20 ℃. Reduction in flexural capacity was observed with temperature, failure mode was also shifted from flexural mode to debonding mode of failure at elevated temperature. Ultimate shear load and failure modes were predicted by truss analogy approach. Debonding model was proposed by incorporating bi-surface interfacial shear strength, close agreement were observed between experimental and predicted values.

프리캐스트 콘크리트 트리플 리브 슬래브의 전단성능

최근, 건물의 자중을 저감시킴으로서 시공성을 향상시키기 위한 방안으로 중공 PC슬래브에 대한 관심이 높아지고 있다. 국내에서 생산되는 대표적인 중공 PC슬래브인 HCS는 생산방식 특성상 전단보강근의 배근이 어렵기 때문에 안전성 및 사용성 측면에서 문제가 제기되고 있다. 이와 같은 측면에서, 최근 새로운 형태의 부분 PC 슬래브 시스템인 Tripple Ribs Slab (TRS)가 개발되었다. TRS는 전단보강근의 배근이 가능한 하프PC형 중공슬래브이다. 본 연구에서는 TRS의 전단성능을 검토하기 위해 전단실험을 진행하였다. 시공단계별로 형성되는 단면조건에 대하여 비대칭 1점 가력으로 실험하였으며 실험결과 강도를 기준 식들과 비교하였다. 실험에서의 변수는 CIP 유무와 래티스바의 유무 또는 래티스바의 종류이다. 실험으로부터, TRS는 설계하중을 충분히 지지할 수 있는 전단성능을 가지고 있으며 실험체의 강도는 국내콘크리트구조기준에서 제시하는 일반식으로 적절하게 예측될 수 있는 것으로 나타났다. CIP가 타설되지 않은 시공단계에서는 래티스바의 기여도가 현저히 낮기 때문에 래티스바의 전단강도를 제외하고 설계하는 것이 바람직하다고 판단된다.

Engineering Rock Mass Evaluation for a Multi-purpose Hydroelectric Power Plant: Case of Genale Dawa (GD-3), Ethiopia

In engineering projects such as tunnels, dams, foundations, and slope stability, the strength and elastic properties of the intact rock affect both the project design and the construction operation. Geological, geophysical and geotechnical study have been carried out for construction of multipurpose hydroelectric power plant at Genale–Dawa (GD-3) on the Genale River with the goal of generating 254 MW of hydroelectric power and providing irrigation water for downstream agriculture. The dam site is located on massive pegmatoidal granites with minimal foundation excavations and minimal grouting requirements. Weathering at the dam site is generally less than about 5 m. In general the Lugeon tests have shown that the rock mass at the dam site is generally tight below 6 m but this could extend to 10 m or possibly more in places. In the power house area weathering extends to about 15 m on the ridge and about 9 m in proximity to the river. This deeper weathering is probably due to the presence of schists within the granites as the foliated schists with significant mica content are more prone to weathering. Point load test, laboratory UCS tests and correlation of P-wave velocity with UCS is considered in assigning the reliable value of rock strength. Combined three input parameters RMR, Q system and RMi system were used for the assessment of the rock mass strength of tunnel and dam foundation. The tunnel will be excavated largely in the pegmatoidal granites with a Rock Mass Classification of “Very Good” to “Good” This is largely due to the massive, relatively un-jointed rock mass of high strength. There is a section of headrace tunnel, of uncertain length and at the surge shaft in proximity to the outlet portal, where significant proportions of the pegmatoidal granites contain remnants of feldspathic and biotite schists, the Rock Mass Classification of this unit is “Fair” to “Good”. The proposed hydropower project is situated in a geologically favorable environment with very suitable foundation and tunneling conditions. The study lists recommendations in relation to testing and rock classification procedures, which are indirectly related to the safety and quality of the hydropower infrastructure.

Empirical correlations for predicting strength properties of rocks – United Arab Emirates

In United Arab Emirates (UAE) and the Arabian Peninsula, most of the rocks are sedimentary in nature and mainly consist of sandstone, mudstone and crystalline gypsum. The identification of rock properties is beneficial for the construction work and design projects. Unconfined compressive strength (UCS) is the most frequently used method and is usually determined from laboratory tests, among the different strength parameters. A study was undertaken to assess estimating strength parameters from empirical correlations of such rocks and to develop the governing predictive equations. In order to conduct this study, 420 soil samples were collected from various locations in the UAE and were tested for various observations including point load test (Is(50)) and ultrasonic velocity (USV) through its pulse velocity. The results indicated that the nomographs could predict well the unconfined compressive strength within ± 10% confidence interval for both Is(50) and USV. The accumulating experience over many years of rock testing in our laboratories and other geotechnical investigation laboratories in the area suggested that there exists an underlying trend that governs the strength characteristics of such rocks.

Experimental study on the shear behaviour of precast concrete hollow core slabs with concrete topping

In typical precast construction practice of floor slabs using precast concrete hollow core unit (HCU), in-situ concrete is cast on top of the HCU to obtain smooth and even floor finish. The surface of the HCU is seldom given proper treatment prior to casting the concrete topping. The texture and surface moisture condition of the HCU just before receiving concrete topping may affect the overall strength of the slabs when the concrete topping and the HCU act compositely during service. This paper presents the experimental study on shear-flexure capacity of composite slabs using HCU and concrete topping. Full scale three point load test are carried out on 14 composite slab specimens with different surface roughness and surface condition of the HCU before casting the concrete topping. The surface roughness considered is smooth and rough, while the moisture conditions are dry, ponded and optimum wet. The effect of the longitudinal joint between the HCU panels is also considered. The experimental results are also compared with predicted values using the available equation in Eurocode 2 and an equation published by a previous researcher. The results of the experiment show that the HCU surface condition and longitudinal joint affect the stiffness and shear-flexure strength of the slabs. The optimum HCU surface condition which can produce highest stiffness and shear strength is rough and wet conditions, while the longitudinal joint between HCU panels reduces the slab shear strength. The interfacial horizontal shear is not the factor that governs the strength and behaviour of the slabs. The equation available in Eurocode 2 gives non-conservative prediction of the shear strength. In contrary, the equation published by the previous researcher gives conservative prediction of the shear strength.