ASTM C1202 Research Articles

Using post-cracking strength to determine flexural capacity of ultra-thin whitetopping (UTW) pavements

Utilizing fibrillated polypropylene fibers (FPP) in Ultra-thin whitetopping (UTW) has become increasingly popular to improve the flexural capacity of concrete slabs. The calculated flexural strength (i.e., modulus of rupture (MOR)) depends on the elastic formula of ASTM C78 does not illustrate the fiber’s benefits. Therefore, the concept of effective modulus of rupture (MOReff.) that is determined from the equivalent flexural strength ratio has been used to quantify the added flexural capacity of fibers on unreinforced concrete. The purpose of this study is to investigate the benefits of testing the FRC/asphalt composite beam on the flexural capacity of UTW. Three main parameters have been taken into consideration: FPP content, pavement thickness, and failure mode. Furthermore, comparison was made to verify the effectiveness of composite beams for flexural capacity. Six different cases of concrete beams and ten cases of FRC/asphalt composite beams were performed. The results of the composite beam showed that the flexural capacity was higher than the capacity of the concrete layer. In addition, using FPP in the composite beams improved the MOReff.. The results also revealed that testing UTW under noncommon failure modes did not reflect the real flexural capacity of UTW. The required UTW thickness depends on the proposed flexural capacity of the composite beam being less than the required thickness that is calculated depends on the concrete beam.

Effect of Saw Dust Ash and Eggshell Powder on the Properties of Cement Blends

The presence of calcium hydroxide (CH) can pose deteriorating effect on the durability of the cement from the inclusion of Eggshell powder (ESP) into the cement matrix. The incorporation of supplementary cementitious materials (SCM) such as Saw dust ash (SDA) could improve the properties of ESP-cement blends by eliminating some undesirable effects at the later age. This paper tries to explore the effect of possibility of replacing eggshell powder (ESP) cement blend with SDA and cement replacement on the properties such as consistence, setting times, volume expansion and strength gain. Saw dust was calcined at 600°C for 1 hour and sieved with 90µm sieve to obtain SDA. Portland limestone cement CEM II A-L was blended with ESP was replaced with SDA between 0 – 20 wt.% at 5 wt.% intervals and 0 -12.5 wt.% at 2.5 wt.% interval for physical properties and mortar compressive strength using 50 mm cubes with mixing ratio 1:3:5 (water, binder and sand) respectively. The chemical analysis of SDA revealed a high silica content (56.81 wt.%) with SiO₂+Al₂O₃+Fe₂O₃ > 70% (72.2 wt.%), thus classified as Class F pozzolan according to ASTM C618 while ESP indicated a high lime content (48.5 wt.%) and considered a filler. Results indicated an increase in the consistence and setting time of the ternary blends as ESP was replaced with SDA owing to the unburnt carbon present in the SDA as well as clinker diminution. Likewise, an increase in the cement replacement led to an increase in water consistence and setting times. The retarded setting times of SDA-ESP cement blends could be attributed to increased water required due to SDA’s unburnt carbon whereas, ESP-cement blend produced accelerated setting times. A decrease in the volume expansion of the cement blends was observed as ESP was replaced with SDA which could be attributed to the decrease in the available lime while an increase in the volume expansion was also experienced as the cement replacement was increased from 0 – 20 wt.% at various SDA/SDA-ESP ratios from 0 – 0.8 except ratio of 1.0. The mortar compressive strength of cement blended with ESP and SDA experienced an increase as curing age was lengthened despite clinker diminution. This enhanced strength could be linked with SDA’s pozzolanic reactivity, provision of nucleation sites and formation of muscovite resulting in denser CSH with the optimal cement replacement observed at 5 wt.% with SDA/SDA-ESP ratio of 0.2 and 0.4 respectively.

The utilization of sandblasting sand waste for mortar and normal concrete

Nowadays, large amounts of sandblasting sand waste are being produced and pollute environment. Sandblasting utilize to remove accumulated organic matter and other debris on concrete, steel, and wood components. The objective of experimental Laboratory for an analyse utilization of sandblasting waste in term of mortar strength, concrete strength, absorption and work ability of the mix. An experiment was conducted at civil laboratory POLINEMA using mortar cube 10 × 10 cm, and cylindrical concrete mould ø 15 × 30 cm, the curing time 3 and 7 day for mortar, 7 and 28 days for concrete. The testing refere to ASTM C-150 for mortar and Normal concrete with SNI-03-2834-2000. Fraction of waste sand are 0%,10%,20% and 30% of natural sand. The result, mortar compressive strength 3 days, 120 kg/cm2(0%), 125kg/cm2(10%), 129kg/cm2 (20%), and 131kg/cm2 (30%). For 7 Days, 190 kg/cm2(0%),200 kg/cm2(10%), 203 kg/cm2 (20%), and 213kg/cm2 (30%). For concrete strength 7 days, 150 kg/cm2 (0%), 161 kg/cm2 (10%), 168kg/cm2 (20%),174 kg/cm2 (30%), For 28 days, average concrete strength 225 kg/cm2 (0%),259 kg/cm2 (10%), 269 kg/cm2 (20%),272kg/cm2 (30%). An absorption decrease 8%(0%), 5%(10%), 4.5%(20%), and 3.9%(30%), work ability of the mix increase 3.5cm (0%), 3.57 cm (10%), 4.5cm (20%), and 4.9 cm (30%), that is indicated by slump value.

A Modified Chemical Index to Predict Fly Ash Dosage for Mitigating Alkali-Silica Reaction

Abstract It is well chronicled that coal fly ash can mitigate the risk of alkali-silica reaction (ASR) in concrete structures. However, the efficacy of individual fly ashes is highly dependent on their chemical composition. Prescriptive requirements for ASR mitigation have largely focused on whether the fly ash is classified as Class F or Class C per ASTM C618, Standard Specification for Coal Fly Ash and Raw or Calcined Natural Pozzolan for Use in Concrete, whereas performance requirements may require extensive testing to satisfactorily demonstrate mitigation potential of a fly ash. Previous research established the need for an accurate model to predict required fly ash replacement rates for ASR mitigation based on the chemical constituents of cement and fly ash. Therefore, a new model is proposed to account for the availability of each chemical constituent from cement and fly ash separately, utilizing ASTM C1260, Standard Test Method for Potential Alkali Reactivity of Aggregates (Mortar-Bar Method), and ASTM C1567, Standard Test Method for Determining the Potential Alkali-Silica Reactivity of Combinations of Cementitious Materials and Aggregate (Accelerated Mortar Bar Method), test data. The successful development of models based on 14-day and 28-day expansion data from these tests is presented in this article.

Relating water permeability to electrical resistivity and chloride penetrability of concrete containing different supplementary cementitious materials

Electrical test methods for predicting concrete penetrability have been widely accepted for use in assessing quality and durability of concrete; however, these methods are indirect and have not been related to concrete water permeability. This research compares three standardized electrical test methods, AASHTO T 358, AASHTO TP 119, and ASTM C1202, to hydraulic/water permeability. As no consensus standardized water permeability test method is available, a uniaxial, steady-flow permeameter test that has generally been used within the research community was employed for this research. The results demonstrate that the electrical test methods investigated for predicting concrete penetrability are not necessarily appropriate for concrete mixtures containing alternative supplementary cementitious materials. Materials with electrically conductive components in pore solution or bulk matrix perform poorly in electrical testing such as surface or bulk resistivity, or chloride ion penetrability testing, although water permeability indicates comparable performance to traditional supplementary cementitious materials.

Thermal and sound properties of concrete mixed with high porous aggregates from manufacturing waste impregnated with phase change material

In this study, the properties of lightweight concrete manufactured from high porous aggregates impregnated with phase change material (PCM) were investigated. The aggregates used are in the form of waste retrieved from the manufacturing process of autoclaved aerated concrete block (ACC). The PCM (paraffin type) was used to impregnate the blocks at about 65% by weight. The non-PCM aggregates were replaced by PCM aggregates from 25 to 100% by volume. Five experiments were carried out: density and absorption (ASTM C138), compressive strength (EN12390), flexural strength (ASTM C78), thermal behavior, and sound transmission loss. Results showed increasing trends in density, compressive, and flexural strength with the increase PCM aggregate content. Thermal behavior is also found to improve with increasing PCM aggregates. Sound transmission loss, however, was found to decrease with increasing PCM aggregates.

Prospective of sugarcane bagasse ash for controlling the alkali‐silica reaction in concrete incorporating reactive aggregates

AbstractSugarcane bagasse ash (SBA) is a supplementary material widely used around the world for improving mechanical and durability properties of concrete. Main aim of this study was to examine the potential of SBA for controlling alkali‐silica reaction (ASR) in concrete incorporating reactive aggregates. SBA and reactive aggregates were acquired from local industry and quarry. Mortar bar specimens were cast to investigate various dosages of SBA (i.e., 10, 20, 30, and 40% by cement weight) for mitigating the alkali‐silica reactivity expansion as per ASTM C1260. Petrography analysis of aggregates revealed the presence of deleterious minerals, which are prone to ASR. Strength activity index and thermal analysis results confirmed the pozzolanic activity of SBA. Mortar bar results showed 20 and 40% decrease in ASR expansion for specimens incorporating 10 and 40% of SBA by cement weight, respectively. Moreover, scanning electron microscopy analysis showed no sign of cracks due to ASR for specimens incorporating SBA. The improved behavior of specimens with SBA addition was due to alkali absorption and dilution process leading to low CaO/SiO2 ratio, confirmed through energy disperse X‐ray spectroscopy. Therefore, it can be envisioned that full‐scale implementation of SBA addition in concrete mixtures could mitigate land filling of this by‐product and lead toward the development of eco‐friendly and sustainable technique for controlling the ASR associated damages in concrete structures.

Durability study of AAMs: Sulfate attack resistance

This paper is a part of works intended to determine more appropriate durability test methods for alkali activated materials (AAMs). Indeed, the current methods used to characterize durability of AAMs are those initially developed for ordinary Portland cement (OPC) and blended OPC. As the chemistry that governs both AAMs and OPC systems is completely different, using OPC durability methods for AAMs could induce inaccurate results. This work aims to study sulfate resistance of alkali activated slag (AAS), alkali activated fly ash (AAFA) and OPC (used as reference) to propose appropriate sulfate resistance test for AAMs by using ASTM C1012 as a basis. Both temperature of curing and sodium sulfate concentration were studied. Expansion of samples was evaluated over time. Results showed that all the OPC bars exceeded the limit compliance with less expansion for those precured at 35 °C. The expansion was attributed in all cases to gypsum and ettringite formation. AAS samples underwent expansion that remains below the limit compliance. At high curing temperature, an initial high expansion attributed to water absorption by the formed porosity was observed. For AAFA systems, no expansion was detected whatever the curing regime and the sulfate concentration, showing a great resistance of such systems to sodium sulfate attack.

Durable concrete specification development and implementation for the New International Airport of Mexico

This paper reviews the concrete specification development for the New International Airport of Mexico (Nuevo Aeropuerto Internacional de Mexico, NAIM). The first phase involves the pour of more than 3 million m3 of concrete of different specifications to fulfill the requirements of the variety of structures. Concrete durability is one of the top priorities given the lake soil conditions, which includes the presence of chlorides, sulfates and other components that potentially implies a high severity structure durability risk. This article focuses on the specification development, industrial implementation and concrete performance review through Mexican and International test methods. An outstanding landmark has been set up in Mexico through this project on the engineering, construction materials and techniques. An overview of the local concrete component materials, mechanical, workability, low permeability (ASTM C1202, BS EN 12390-8, NT Build 492 and NMX C514) and crack self-healing (Mexican Procedure) properties are presented.From the diferent concrete technology approaches, the densification with silica fume and the crack self-healing ability provided by a proven permeability reducing admixture for concrete exposed to hydrostatic pressure conditions (ACI 212 type PRAH), were preferred. The performance of two mix designs is presented. High resistivity to chloride ion and water under pressure ingress, as well as crack self-healing ability of at least 80% where demonstrated under standard test methods. The information provided in this paper corresponds to the bid base line.

Experimental investigation of pozzolanic concrete containing wheat straw ash

This study investigated the detailed optimization of wheat straw ash (WSA) as a pozzolanic material. Characterization of WSA as pozzolanic materials was carried out according to ASTM C618 and results indicated that WSA calcined at 700 °C for 2 h fulfilled ASTM C618 requirement and results were also confirmed by X-ray diffraction (XRD) analysis of WSA samples. Effect of WSA on setting time, mechanical properties, alkali–silica reaction (ASR), hydration process, and microstructure of cement paste (CP) and concrete was studied. Compressive and flexural strength of concrete mixture containing 14% WSA was 7.5% and 19.5% more as compared to control mixture at 28 days respectively. ASR expansion of mortar prisms and hydration temperature was reduced due to WSA incorporation. XRD and scanning electron microscopy investigations of CP indicated that WSA improved the microstructure of CP and was effective in imparting the pozzolanic characteristics during hydration reaction at 7 and 28 days.

Effect of mineral admixtures on early age properties of high performance concrete

In effect, the early age characteristics of concrete practically determines the performance of concrete during service. While several factors influence the fresh nature of concrete, water-binder (w/b) ratio and admixtures are particularly the most important. In this study, the effect of Nano-silica (NS) and fly ash on early strength characteristics of an M50 grade of high performance concrete was investigated. The contents of fly ash and Nano silica were used in varying proportions, from 28% to 32% and 1.0% to 2%, respectively, by weight of cement in the mix. Natural river sand was partially replaced by manufactured sand (M-sand) at 0%, 50% and 100% levels. Concrete mixture was achieved at 0.39 water/binder ratio. The workability and setting time of fresh concrete, by slump and penetration resistance tests, respectively, were determined as per ASTM C-403. The strength development at the early age was investigated and compared with that of the control concrete, based on tests on cube and cylinder specimens. Based on the obtained results, the early age strength of HPC containing NS was improved than the results obtained using the IS: 456-2000 code recommended models.

Mechanical Behaviour of Composite Material Based on Mortar/Natural Fibers (Fique <i>"Furcraea andina"</i>) Meshes as External Reinforcement of Concrete Beams

This work shows the effect of an external reinforcement of concrete beams using a composite material based on woven meshes obtained from natural fibers of fique "furcraea andina" embedded in a Portland cement mortar. Fique is an endemic plant of the Colombian Andean region. The woven meshes tensile resistance was obtained according to the ASTM D-5034 standard. Flat orthogonal woven meshes were characterized, made with 714.3 tex linear density yarns, separated 3, 5 and 8 mm in warp and weft directions, likewise, the concrete beams rupture module was evaluated according to the ASTM C78 standard. Beams were tested, both without mesh reinforcement and with external reinforcement. Beams were reinforced on one, three and four of their faces. A commercial epoxy adhesive was used to glue the composite material to the concrete beams and their behaviour were tested with and without the application of the epoxy. The four faces reinforced composite beam showed an increase of 80% of its bending resistance compared to the beam without any additional reinforcement, showing a greater ductility and better mechanical behaviour. The results of this study demonstrate the effectiveness of the use of fique meshes as alternative reinforcement agents for cementitious compounds in structural elements, opening the way for future investigations into the use of natural fibers in construction alternative materials.

Influence of the moisture state of recycled fine aggregate on the impermeability of concrete

Abstract The impermeability of recycled fine aggregate concrete (RFAC) with different contents of recycled fine aggregate (RFA) was tested according to the standard test method of ASTM C1202. The moisture states of RFA were controlled at air-dried (AD), oven-dried (OD) and saturated surface-dried (SSD) states. Both the interfacial structure and the pore structure of RFAC were analyzed. Research results show that, for the same total water-cement (TWC) ratio and the same content of RFA, the interfacial transition region of RFAC became denser by increasing the moisture amount of RFA from oven-dried, air-dried to a saturated surface-dried state; meanwhile, the density and porosity of hardened cement paste (HCP) improved as well, which resulted in the higher impermeability of RFAC. Whereas by contrast, for the same moisture state and by increasing the RFA content, both the interfacial transition region and the property of the interface structure of RFAC became weaker. Also, the decreasing density and porosity of HCP resulted in lower impermeability of RFAC.

Distribution of ASR gel in conventional wet-mix glass mortars and mechanically produced dry-mix glass blocks

The alkali-silica reaction (ASR) of recycled glass mortars prepared by the traditional wet-mix and the mechanically compacted dry-mix methods using a same aggregate-to-cement (A/C) ratio was examined based on the ASTM C1260 accelerated mortar bar test method. The test results showed the expansion values of the dry-mix glass blocks were within the threshold of ASTM C1260 while the wet-mix glass mortars were above the threshold. The mercury intrusion porosimetry (MIP) results of the dry-mix blocks showed a new peak in the larger pore size range between 10 µm and 100 µm in the differential curves, and the porosity in this ranges decreased after the ASR test. As revealed by scanning electron microscopy-backscattered electron (SEM-BSE) image analysis, the mitigation of ASR expansion and the decrease of porosity were mainly due to the distinctive different distribution of ASR gel in the dry-mix blocks. Compared to the ASR gel formed within the glass aggregate in the wet-mix mortars, the ASR gel in the dry-mix blocks was mainly observed on the surface of glass aggregates in the larger pores (between 10 and 100 µm). No ASR gel was observed in the interface between the glass aggregates and the cement paste of both the wet-mix mortars and the dry-mix blocks. The release of the swelling pressure of the ASR gel by the large pore in the dry-mix blocks suppressed the further development of cracks caused by ASR expansion.

Effects of prestressing and saw-cutting on the freeze-thaw durability

There are many factors that affect the freeze-thaw durability of concrete elements, including proper air entrainment system, freeze-thaw durable aggregates, low permeability, and proper curing. While ASTM C666 allows the excising of small freeze-thaw samples from larger sections it doesn't address the issues that can arise when excising samples from prestressed concrete and subsequent testing in freezing and thawing. In order to investigate the effects of saw-cutting, the existence of reinforcement, and use of prestressing, concrete samples of different sizes, with and without saw-cutting, with and without reinforcement, and with and without prestressing were tested in freeze-thaw. The freeze-thaw mechanism was adjusted, from that of ASTM C666, for the larger sample in terms of freezing and thawing rates and the testing method. The results indicate that saw-cutting through plain concrete had minimal effect on the freeze-thaw durability, whereas sawcuts through reinforcement were shown to be very detrimental to the measured durability in the tests.

Characterization of scoria rock from Arabian lava fields as natural pozzolan for use in concrete

The feasibility studies of using alternative cementitious materials (ACMs) in concrete construction are conducted using various characterization tests. Different samples of scoria rocks (SR) were procured from different regions of the Arabian Shield and investigated for use as ACMs. Various methods and characterization techniques were conducted. Characterization results revealed that the pozzolanic activity of SR in mortar does not correlate well with the sum of the main elemental oxides (SiO2+Al2O3+Fe2O3), as per the requirement of ASTM C618. Concrete mixtures containing 30% SR per cement weight were prepared and tested at 28 and 90 days to evaluate the performance of SR for construction applications. Furthermore, the mortar and concrete mixtures containing SR have shown a slow rate of pozzolanic activity at early ages. However, the development in compressive strength was enhanced at later ages dependent on the mineralogical compositions of SR. It is concluded that the improvement in strength could be corroborated based on the formation of tobermorite-like structures, as confirmed using XRD and thermal analyses. These structures result from the reaction of minerals of amorphous sodium aluminosilicate phase (albite minerals) in SR with portlandite liberated during cement hydration. Conclusively, SR reacts as a pozzolan not as a filler.

A Study of Strength Activity Index of Pozzolan and Silica Sand with Ordinary Portland Cement Using ASTM C595 / C595M-12 Method

Strength Activity Index (SAI) is a method that aims to see the quality of additional materials mixed into the cement. The additional materials examined in this study were pozzolan from Lubuk Alung, pozzolan from Sicincin, and silica sand from Payakumbuh. This study refers to the ASTM C595/C595M-12 standard. The process started with placing specimens and mold (on a base plate) in a humid room or closet and protecting the surface from water droplets. After the mold was removed from the humid room or closet, the cubes were removed from the mold. The cubes were placed in suitable metal or glass containers, and the containers were sealed and stored at a temperature of 38.0±2.00C for 27 days. The specimens were cooled to 23.0±2.00C before the tests were carried out. The compressive strength results of pozzolan from Lubuk Alung, pozzolan from Sicincin, and silica sand from Payakumbuh were 327 kg⁄cm2, 296 kg⁄cm2 and 199 kg⁄cm2 respectively. Thus, the specimens which fulfilled the SAI requirement according to ASTM C-618 were pozzolan from Lubuk Alung and pozzolan from Sicincin with 91.34% and 82.68%, respectively. In contrast, silica sand from Payakumbuh did not fulfill the requirement of ASTM C-618 at a minimum of 75% because the result obtained was only 55.58%.

Machine learning can predict setting behavior and strength evolution of hydrating cement systems

AbstractSetting and strength development of ordinary Portland cement (OPC) binders involves multiple interacting chemical reactions, resulting in the formation of a solid microstructure. A long‐standing yet elusive goal has been to establish a basis for the prediction of the properties and performance of concrete using knowledge of the chemical and physical attributes of its components—PC, sand, stone, water, and chemical admixtures—together with the environmental conditions under which they react. Machine learning (ML) provides a data‐driven basis for the estimation of properties, and has recently been applied to estimate the 28 days (compressive) strength of concrete from knowledge of its mixture proportions (Young et al, Cem Concr Res, 2019, 115:379). Building on this success, the current work uses a diverse dataset of ASTM C150 cements, the chemical composition and other attributes of which have been measured. ML estimators were trained with this dataset to estimate both paste setting time and mortar strength development. The ML estimation errors are typically similar to the measurement repeatability of the relevant ASTM test methods, and are thus able to account for the influence of binder composition and fineness. This creates new opportunities to apply data intensive methods to optimize concrete formulations under multiple constraints of cost, CO2 impact, and performance attributes.

Environmental impact and durability of carbonated calcium silicate concrete

This paper describes the environment impact of low-lime calcium silicate (Ca2SiO4) cement (CSC) that cures by a reaction with gaseous carbon dioxide (CO2). The production of CSC requires less limestone and lower kiln temperatures than those used for ordinary Portland cement (OPC). This makes it possible to reduce the carbon dioxide emissions at the cement kiln from ∼810 kg/t for OPC to ∼565 kg/t for CSC. The carbon dioxide used in the curing process and captured within CSC-based concrete (CSC-C) is industrial-grade carbon dioxide sourced from waste flue gas streams. The fully hardened CSC-C will contain up to 300 kg of carbon dioxide per tonne of cement used in the concrete formulation. This paper also summarises the performance and durability of CSC-C and OPC concrete (OPC-C). Freeze–thaw and scaling resistance were evaluated as per ASTM C666 and ASTM C672, respectively, the concentrations of ionic species leached from the concretes were measured, efflorescence was evaluated in pavers partially submerged in water, and the expansion and mass changes associated with the exposure to sodium sulfate (Na2SO4) and magnesium (Mg) solutions were measured. In each of the durability tests, the CSC-C specimens, made with commercially produced Solidia Cement, performed equivalently or better than the OPC-C specimens.

Enhancement of Rigid Pavement Capacity Using Synthetic Discrete Fibers

Adding synthetic discrete fibers to unreinforced rigid pavements has been significantly increased during the last decades. Synthetic fibers improve flexural capacity, toughness, fatigue resistance, and durability, and reduce crack width. Most design methods of rigid pavements adopted modulus of rupture (i.e., flexural strength) as the primary parameter in the input design process. The elastic modulus of rupture, which has calculated depending on ASTM C78 formula does not reflect the benefits of the synthetic fiber. The effective modulus of rupture (MOR’) has been proposed to quantify the added capacity of fibers over unreinforced concrete, which is calculated depending on the equivalent flexural strength. This study aimed to determine the flexural capacity of rigid pavement, which included filtrated polypropylene discrete fibers. The concept of the effective modulus of rupture was adopted to calculate the capacity of rigid pavements. Adding Polypropylene in concrete reduced the compressive strength, modulus of elasticity, elastic modulus of rupture, while improves effective modulus of rupture and flexural toughness.