Ultrasonic Pulse Velocity Test Research Articles

Drilling resistance testing combined with SonReb methods for nondestructive estimation of concrete strength

This study explores a drilling-based test methodology for nondestructive estimation of in-situ concrete strength. An experimental campaign has been carried out to develop a relationship between the drilling-resistance parameter, DR, and compressive strength of concrete. Rebound hammer (RH) and ultrasonic pulse velocity (UPV) tests were also performed and multivariate regression models complementing DR with RH and UPV data have been developed. A machine learning approach utilizing support vector machines (SVM) was implemented. The experimental data support that combined usage of DR with UPV and/or RH provides a robust tool for compressive strength prediction. Even with the limited data available, the support vector regression model shows promising performance.

The use of drilling test to investigate the salt distribution in air lime mortars

• Drilling test (DRMS) to map salt distribution in air lime mortars. • Processing of drilling data to detect salts within air lime mortars. • Diagnostic techniques to evaluate the presence of salts and salt damage in air lime mortars. One of the principal causes of deterioration in historic buildings is the presence of salts. Porous and low-strength materials, such as soft mortars, are particularly susceptible to the deteriorating action of salts. The most severe damage occurs when salts accumulate behind the material surface, causing crumbling, exfoliation, and spalling. For this reason, the use of minimally invasive techniques to locate the presence of salts below the surface can be helpful to make an informed decision on the best practice for conservation strategies. In this work, the effectiveness of the drilling test in investigating the sub-surface distribution of salts in two lime-based mortars was evaluated. The technique proved to be effective as the increase in the recorded drilling forces was well correlated with the salt content measured within the materials. In particular, the drilling test results showed a similar behavior between the two mortar mixes. This finding was confirmed by the ultrasonic pulse velocity tests, visual observations, and weight loss measurements performed after the salt aging test. Another aspect of the work is the contribution to the processing of drilling profiles in salt weathered soft mortars. Indeed, the results of drilling tests in soft mortars are very scattered due to the intrinsic heterogeneity of these materials. Thus, the proposed processing of drilling data was effective in evidencing the effects of salts, by reducing the influence of the chip formation on the drilling profiles.

Correlation of non-destructive and destructive testing of concrete modified with rice husk ash and brick aggregate

Concrete structures may deteriorate over a period of time. Nowadays, to determine the extent of damage, various tests are being performed that are non-destructive by nature. A proper correlation between destructive testing (DT) and non-destructive testing (NDT) may enhance the use of NDT applications in the field of concrete structures. Although several correlations have been suggested by other authors for standard concrete, the correlation may change with the use of non-conventional materials such as rice husk ash (RHA) and brick aggregate (BA) in concrete. In this paper, NDT methods such as ultrasonic pulse velocity (UPV) testing and rebound hammer testing, as well as DT methods such as compressive strength testing, were performed on a special type of concrete in which BA was used as coarse aggregate and RHA was used as the partial replacement of cement. This modified concrete has been abbreviated as RHA-BA concrete. Material-specific prediction models based on linear regression and artificial neural network (ANN) were established after using the data from concrete specimens. A strong correlation was observed between NDT and DT when the RHA percentage was low. The best correlation between NDT and DT was found at 5% RHA. An RHA percentage beyond this yields a weaker correlation between NDT and DT. The linear regression model along with the k-fold validation technique and the ANN model have both proven to be efficient in predicting the compressive strength of RHA-BA concrete; however, the ANN model has proven to be more efficient than the linear regression model with a lower mean squared error (MSE) and higher R-square values.

Recycling of Concrete Demolition Waste Powder as a Sustainable Material in Portland Cement Pastes Modified with Nano-silica

In recent years, researchers dedicated themselves to explore the possibility of introducingconcrete waste powder (CWP) into Portland cement as a sustainable material for Portland cement to reduce as possible the environmental pollution with this concrete demolition wastes. To optimize the effect of CWP on cement-based materials, this paper usesnano-silica (NS) to improve the hydration and mechanical properties of cement-based materials with CWP. Results indicated that after adding NS into CWP cement pastes, the setting time of cement pastes was significantly reduced, while the early rate of hydration and hydration heat increased. Besides, the mechanical strengths of the cement pastes increased as CWP replaced at the expense of the cement only up till 15 weights %, and then decreased. The addition of nanosilica (NS) can compensate the mechanical strength loss caused by CWP as supplementary cementing materials. The higher ratios of CWP than 15 weight % increased the pore volume or porosity. In contrast, NS in CWP blended cement significantly decreased the porosity, and increased the proportion of harmless pores. Hence, NS reduced the porosity, which in turn improved and enhanced the bulk density and mechanical properties. The optimum amount of NS is 2.5 weight % which resulted in the best results. The heat of hydration of the different cement batches in the two groups adversely affected with the incorporation of CWP, but little improved with NS. The obtained results were confirmed by the ultrasonic pulse velocity (USPV) test, where the cement batch PP15 (Group I) and PS2.5 (Group II) achieved the highest conformance.

QUICK RESPONSE USING FORENSIC ENGINEERING ON STRUCTURAL BUILDING DAMAGE

Quick response and emergency when buildings are damaged by earthquakes and other situations to determine the causes and ensure that the structure of the building can still be used safely. The additional building of one the heritage buildings in Jakarta currently being used as an office was observed to have suffered damages in the form of torsion of the beams, cracks in beams and walls, as well as the subsidence in floors. Therefore, this research was conducted to investigate these sudden and quick damages using forensic engineering through visual observations, Ultrasonic Pulse Velocity testing, Profometer, Cone Penetration Test, Ground Penetrating Radar, and structural analysis. The visual observation results showed the existence of cracks in the beams, walls, and columns as well as a maximum deformation of 94 mm, especially in the dilation area or the border between the main building and the additional building around the lobby and the floors above it. Moreover, the improper structural system caused the damage as observed with one column having an ultimate axial load of 114 tons while the surrounding columns were only 25-50% of this value. The quick response provided was observed to be the addition of steel columns, beam strengthening with FRP, and zoning of usable space in buildings. The quick response also showed the main damage was caused by the dewatering work of the office construction project near the building and this can be used by the building owner as the basis to submit a claim to the responsible party.

On the Variability of Conversion Models for Concrete Strength Assessment Based on Pulse Velocity Measurements

Abstract The existence of a wide reinforced concrete (r.c.) building stock, which is reaching the end of its service life, has focused the attention on its vulnerability assessment. The first step of this analysis is the estimation of the concrete compressive strength. In this field, many codes allow to supplement the classical destructive tests with nondestructive ones, because of their versality and of the possibility of reducing the time spent for tests. It is worth noting that the spread of these tests is strictly connected to the accuracy of the conversion models, which correlate the nondestructive measurements to the concrete strength. The present paper deals with this issue by examining the results of the experimental investigations, which made use of destructive and ultrasonic pulse velocity tests, on three r.c. buildings in Bari (Italy). The data are analyzed and rearranged to define several testing conditions, for each one of which a conversion model is calibrated. Moreover, the variability of the parameters of the identified models is discussed with respect to the number of data considered in the calibration process, to the chosen model, and to the accuracy of the assessed strength.

Mechanical properties, flexural behavior, and chloride permeability of high-performance steel fiber-reinforced concrete (SFRC) modified with rice husk ash and micro-silica

To improve the fiber-matrix bond and enhance the macro-mechanical performance of SFRC, this study is focused on the modification of the cement matrix by using two eco-friendly supplementary cementitious materials (SCMs), rice husk ash (RHA) and micro-silica (MS). The modification effects of SCMs on the steel fibers were observed and characterized by conducting several macro-mechanical tests i.e., compressive strength, splitting tensile strength, and load-deflection behavior. Besides that, ultrasonic pulse velocity, water absorption, and chloride migration tests were performed to characterize the durability of modified SFRC mixes. The results showed that the incorporation of RHA and MS at low levels notably enhanced the efficiency of steel fibers under splitting tensile and flexural strength testing. SFRC made with 7.5% MS and 7.5% RHA showed 79% and 96% more flexural strength than plain concrete (PC), respectively. Whereas SFRC experienced 14% and 26% further improvement in flexural toughness with the addition of 7.5% RHA and 7.5% MS, respectively. The addition of 7.5% and 12.5% RHA showed a beneficial effect on the resistance of SFRC against the penetration of chloride ions and water. The results of this study confirmed the synergistic interaction of steel fiber and SCMs.

Prediction of Compressive Strength of Normal Concrete with Partial Replacement of Sand by Waste Glass Using Fuzzy Model

The objective of the study is a partial replacement of natural fine aggregate with crushed waste glass for M 30 concrete production. To determine the compressive strength of such concrete for using 10% 15%, 20%, and 25% of partial replacement including control samples using 0.45, 0.47, and 0.50 water-cement ratios. Quality tests, slump, compressive strength, density, permeability, and Ultrasonic pulse velocity test are performed; the cube of concrete mix design test follows the American Concrete Institution (ACI) guideline. And to develop a predictive model for the 7days and 28days compressive strength using a fuzzy model. The result has shown that the physical properties, of course, fine aggregate and crushed waste glass satisfy the standard specification, when the replacement percent increases, the compressive strength and ultrasonic pulse velocity of concrete are increased up to 15% of replacement level Due to the angular nature of waste glass particles contributes more effective cement past. Thus reduction of microscopic voids in concrete. The study also found the depth of penetration for concrete indicates the increased replacement percent increase in the depth of penetration increase due to increase microscopic void space. It was concluded that the natural sand is effectively partially replaced by crushed waste glass, maximum compressive strength was achieved at 15% of replacement level. The result showed that quite satisfactory in predicting the Compressive strength for 7 and 28 days strength of the M-30 concrete mix using the fuzzy logic technique with a coefficient of correlation, R2 of 0.87 and 0.85 respectively for training and validation set. The significance of the study is that the compressive strength of concrete made with partial replacement of natural fine aggregate by the crushed waste glass can be predicted by using the predictive model developed.

Studies on Compressive Strength Microstructural Analysis of Self-Compacting Mortar with Bacteria

This research proposed bacteria-treated concrete, which is highly desirable because the mineral precipitation induced from microbial activities is pollution free and natural. This study investigates the effects of Bacillus Licheniformis, Bacillus Cohnii and mixed bacteria on compressive strength, ultrasonic pulse velocity test, rapid chloride penetration test, microstructural analysis and bacteria cell concentration of 10 5cell/ml of normal and self-compacting mortars made with and without fly ash for 7 and 28 days. With self-compacting mortar, the compressive strength of Bacillus Licheniformis improved by 30.3 % and by adding Bacillus Cohnii in 28 days, the ion penetration value decreased. Finally, it was observed that the deposition of calcium carbonate in mortar improved compressive strength using SEM-EDS and XRD with compound polymorphisms of calcite, vaterite, quartz, and Hautirite.

Effect of adding depolymerized polyethylene terephthalate waste on the acoustic insulation and hardness properties of Iraqi cement mortar

depolymerized Polyethylene terephthalate waste (DPET) particles were prepared by bubble column reactor adding ethylene glycol as a solvent and Nano MgO as a catalyst and using DPET particles to modify the mortar by partial replacement of sand. The mechanical hardness test, the physical ultrasonic pulse velocity test and the acoustic insulation test of the modified cement mortar composite have been studied. DPET particles were used with four percentages of (1, 3, 6 and, 9)%wt of sand for each one of them. All tests were done for 28 days of curing. The cement mortar composite was prepared using water/cement ratio of (0.48) while sand-to-cement material ratio of (1:2.75) (2.75 parts of sand and 1 part of cement). The findings showed that there was no clear influence of DPET on the hardness of the cement mortar, where the hardness of mixture with 3% DPET equal to that of mixture with no DPET was (91.7 shore A), while the hardness of other mixtures with (1, 6 and 9)% PET were (91.6, 91.2 and 90.8 shore A) respectively. While the UPV of the modified cement mortar decrease with increase the amount of DPET particles, where the drops in UPV were (-2.98%) at 9% of DPET particles. The acoustic insulation of the modified cement mortar composite increase as the DPET increases in all frequencies that were used. This is indicate that DPET particles which that made through depolymerized the PET of waste water bottles can enhancement the physical and insulating properties of the mortar.

Non-Destructive Evaluation of Mortar with Ground Granulated Blast Furnace Slag Blended Cement Using Ultrasonic Pulse Velocity.

Non-destructive evaluation using ultrasonic pulse velocity (Vp) testing has extensive applications in the concrete industry. With advances in construction technology, the use of ground granulated blast furnace slag (GGBFS) as a partial replacement to cement in a concrete mix is growing in popularity primarily because it reduces the initial capital cost of raw materials and the associated energy costs. This paper investigates the effect of the water-to-cement (wc) ratio and the cement content replaced by GGBFS on the development with time of the ultimate compressive strength () and the compression wave velocity (Vp) of mortar. The results showed that in the case of mortar with higher percentages of GGBFS replacement (where nucleation surfaces are more abundant), increasing wc can increase but cause a decrease in Vp. The posterior hydration process is highly dependent upon the water particles in the mixture after the first stage of hydration. After 7 days of curing, experimental results show that the of slag blended cement mix design wc ratio of 0.6 surpassed the value of an Ordinary Portland cement. A regression model correlating the and Vp of slag blended mortar is developed, which can be used to predict at concrete ages ranging from 1 day to 28 days for mixes with GGBFS percentage replacement values ranging from 15% to 45%.

Mechanical characteristics of high strength concrete incorporating recycled CFRP fibers

AbstractThe current research article assesses the feasibility of recycled CFRP (Carbon‐Fiber‐ Reinforced‐Polymer) fibers in high‐strength concrete. Different dosages of recycled CFRP fibers (0.2%, 0.4%, 0.6%, 0.8%, and 1%) as well as different aspect ratios of CFRP fibers with 10 and 20 mm fiber lengths is assessed for hardened state characteristics of reinforced high‐strength concrete. Furthermore, ultrasonic pulse velocity test, compression test, flexure test, and impact resistance test are performed to understand the hardened properties of specimens. The chemical composition of various elements present in the various kinds of concrete samples is qualitatively and quantitatively found with the help of energy‐dispersive X‐ray spectroscopy (EDX) equipment. To understand the surface morphology of carbon fibers incorporated in concrete samples, Scanning electron microscope (SEM) photographs are obtained to examine the prepared samples thoroughly. Linear regression analysis, an analytical analysis technique, is incorporated to linearly correlate the different hardened mechanical characteristics of specimens taking into account varying lengths and different dosages of recycled CFRP fiber. The findings reveal that increasing the CFRP fiber dosage and the aspect ratio of recycled CFRP fiber improves the reinforced mix composition's mechanical characteristics.

A Study on Uniaxial Compressive Strength and Ultrasonic Non-Destructive Analysis of Fine-Grained Soil in Seasonally Frozen Regions

Understanding the physical and mechanical properties of soils subjected to freeze-thaw cycles, including both micro and macrostructures, is critical for achieving the required performance of structures employing it as a structural or support material. An experimental study was carried out on clay soil with varying water content (18%, 21.5%, and 23%) after repeated freeze-thaw cycles (0, 2, 5, 7, 12, and 15). The performance of soil was evaluated using unconfined compressive strength (UCS) and ultrasonic pulse velocity (UPV) tests. The experimental results demonstrated that UCS peak values were observed at the lowest water content before and after the freeze-thaw cycles. The stress-strain curves exhibited strain-softening behavior, and this condition transitioned to strain hardening behavior after freeze-thaw cycles with increment in the water content. Moreover, the highest values of UPV were observed to increase UCS values due to capillary forces at minimum water content. Also, an increase in the number of freeze-thaw cycles resulted in a decrease in the UPV. According to correlations between UPV and UCS values, the highest correlations for water contents were obtained at optimum water content, and a decreasing trend was observed after experiencing a number of freeze-thaw periods. In addition, the Grey Correlation Analysis was performed to show the degree of correlation between the UCS and UPV, water content as well as the freeze-thaw cycles. The results demonstrated that the UPV values have a greater impact on the UCS than other parameters.

Effect of waste concrete powder on slag-based sustainable geopolymer composite mortars

In this study, the effect of waste concrete powder (WCP) on slag-based geopolymer composite mortars was investigated. Blast furnace slag (BFS) and WCP were used as binders in geopolymer mortars. WCP was substituted into the geopolymer mortar composites at rates of 10%, 20%, 30%, and 40% by weight of slag. Sodium hydroxide (NaOH) solution was used as the alkali activator in the mixtures and the solution activator concentration was chosen as 16 molars (M). After the prepared mortars were cured at 100°C for 24 hours, they were subjected to flexural strength (ffs), compressive strength (fcs), and ultrasonic pulse velocity (UPV) tests. When the obtained results were examined, it was observed that ffs, fcs, and UPV results decreased with the increase in WCP replacement ratio. These decrements were seen clearly, especially after the 20% replacement ratio. However, despite these decrements, the compressive strengths of all groups were found to be above 50 MPa. In addition, it is thought that environmental pollution can be reduced by using WCP in geopolymer composite mortars.

Study on anisotropy of 3D printing PVA fiber reinforced concrete using destructive and non-destructive testing methods

To further understand the mechanical properties and anisotropy characteristics of 3D printing PVA fiber reinforced concrete (PFRC). This study first obtained 3D printing PFRC mixes with superior mechanical properties through slump tests, penetration resistance tests, printability tests, and flexural tests. Second, the fiber reinforcement mechanisms and anisotropy characteristics of PFRC were analyzed by nondestructive ultrasonic pulse velocity tests, destructive mechanical property tests, and scanning electron microscope tests. Third, the correlation between mechanical properties and ultrasonic signals was analyzed, and the conversion criteria were further established. Moreover, the application range of conversion criteria was also determined. The test results showed that the optimum dosage of PVA fibers is 0.5 wt% for 3D printing FRPC, and the highest cube compressive strength and flexural strength are 98.2 MPa and 6.8 MPa, respectively. The mechanical properties and acoustics of 3D printed specimens showed significant anisotropy. The conversion criteria show a good agreement with the test data and are applicable to 3D printing fiber concrete with a small aggregate size.

VALORIZATION OF DIVERSE SIZES OF COAL BOTTOM ASH AS FINE AGGREGATE IN THE PERFORMANCE OF LIGHTWEIGHT FOAMED CONCRETE

In recent years, research work on the use of coal bottom ash (CBA) as a partial alternative for aggregate in concrete is on the rise. This research is aimed at examining the characteristics of lightweight foamed concrete with CBA as fine aggregate to produce environmentally sustainable product. With the volume replacement technique, CBA was used as 25%, 50%, 75%, and 100% replacement for conventional mining sand with different sieve sizes of smaller than 4.75, 2.36, and 0.6 mm in concrete. Water absorption, porosity as well as mechanical characteristics tests, including compressive strength, splitting tensile strength, and modulus of elasticity (MOE) were conducted and analyzed. X-ray diffraction and scanning electron microscopy microstructural investigations were also performed to correlate test results. The quality of concrete was investigated using a non-destructive ultrasonic pulse velocity test. According to the findings, the highest replacement level of CBA with a sieve size smaller than 0.6 mm had an impact in reducing workability. The effect of CBA particles on water absorption, MOE, compressive strength, and tensile strength depends on the size of the fine aggregate, the replacement ratio and the density. In general, substituting mining sand with CBA aggregate improved the mechanical performance of concrete, notably for the aggregate size of less than 0.6 mm. Moreover, the SEM images indicate that the addition of CBA particles decreased the size and quantity of voids in the foamed concrete.

Development of Test Methods to Evaluate the Printability of Concrete Materials for Additive Manufacturing.

This study proposes test methods for assessing the printability of concrete materials for Additive Manufacturing. The printability of concrete is divided into three main aspects: flowability, setting time, and buildability. These properties are considered to monitor the critical quality of 3DCP and to ensure a successful print. Flowability is evaluated through a rheometer test, where the evolution of shear yield strength is monitored at a constant rate (rpm), similar to the printer setup. Flowability limits were set based on the user-defined maximum thickness of a printed layer and the onset of gaps/cracks during printing. Setting time is evaluated through an ultrasonic wave pulse velocity test (UPV), where the first inflection point of the evolution of the UPV graph corresponds to the setting time of the concrete specimen. The results from this continuous non-destructive test were found to correlate with the results from the discrete destructive ASTM C-191 test for measuring setting time with a maximum difference of 5% between both sets of values. Lastly, buildability was evaluated through the measurement of the early-age compressive strength of concrete, and a correlation with the UPV results obtained a predictive model that can be used in real-time to non-destructively assess the material buildability. This predictive model had a maximum percentage difference of 13% with the measured values. The outcome of this study is a set of tests to evaluate the properties of 3D printable concrete (3DP) material and provide a basis for a framework to benchmark and design materials for additive manufacturing.

İKİ FARKLI POMZA AGREGASI İÇEREN CAM TOZU KATKILI BETONLARIN FİZİKSEL VE MEKANİK ÖZELLİKLERİNİN İNCELENMESİ

In this study, the physical and mechanical properties of concretes produced using basaltic and acidic pumice at different rates were investigated. Pumice aggregates have been replaced by 50% and 100% of normal-weight aggregates. In addition, in order to produce a more environmentally friendly concrete, 5 different mixtures were produced by replacing waste glass powder from cement at the rate of 10%. Unit volume weight, water absorption, porosity, ultrasonic pulse velocity and compressive strength tests were applied to the produced samples. As a result of the study, while the 100% substituted acidic pumice aggregate gave the lowest density, ultrasonic sound transmission velocity and compressive strength values, the water absorption and porosity values were the highest. Except for the concrete mixture containing 100% acidic pumice aggregate, all of the other lightweight concrete mixtures have higher compressive strength values than the compressive strength value of the structural light-weight concrete (17,2 MPa) specified in the TS 2511 standard.

Mechanical and Durability Studies on Concretes Containing Crumb Rubber Fine Aggregate

A growing demand to develop sustainable construction materials, has led to many challenges that are focused to achieve a balance between maintaining the performance characteristics of final product and utilization of non-biodegradable waste materials. There have been numerous attempts to develop concretes by utilizing mineral admixtures and alternate filler materials. In the recent past enormous work has been focused to develop concretes containing crumb rubber as a partial replacement of fine aggregate. In the present study efforts are made to study the mechanical and durability properties of concretes containing crumb rubber as a partial replacement of fine aggregate. The 5% to 20% volume of fine aggregate was replaced with crumb rubber and various mechanical and durability properties were evaluated by compressive strength test, ultrasonic pulse velocity test, Absorption-Desorption studies, Rapid Chloride Penetration Test. The results corresponding to the same are presented.

Experimental Investigation of Crack Initiation and Growth in Concrete Slabs Placed Directly on Clayey Soil

The main objective of this study is to examine the impact of moisture concrete of clayey soil on the concrete slabs placed directly over it. This experimental study presents the mechanical properties of the concrete slab when placed on different clayey soil moisture content ranging from 0% to the optimum moisture content of 35%. The tests were performed on soil concrete specimens of 25*30*50 mm exposed to sprayed water curing conditions for 28 days. Tests of compressive strength, ultrasonic pulse velocity, crack depth and crack width were investigated through this paper. An ejection relationship between compressive strength of concrete and water content in the soil was observed, with a 26% increase with water increasing from 0% to 35%. The opposite was observed in the ultrasonic pulse velocity test, with a decrease of 58% from 0% to the highest water content ratio. As for crack depth and width, it recorded the highest depth and lowest width at 0% water content due to the increased susceptibility of the soil to the absorption of water from the concrete when it’s totally dry. The experiment has shown that the soil moisture content is considered as a critical factor in controlling concrete cracking, and its variation has considerable implications for concrete crack growth.