Alkali-Silica Reaction in Concrete Engineering Suppression Measures of Inquiry

2014 ◽  
Vol 529 ◽  
pp. 26-31
Author(s):  
Wen Bin Qi ◽  
Chun Yan Tian ◽  
Xiao Xin Feng
Keyword(s):  
Fly Ash ◽  
Raw Materials ◽  
Joint Effect ◽  
Test Methods ◽  
Standard Test ◽  
Lithium Hydroxide ◽  
Alkali Silica Reaction ◽  
Local Materials ◽  
Complex Joint

Local materials was used as raw materials in the test. Test methods are standard test methods. It compared the use of fly ash alone or lithium hydroxide used alone inhibited the effect of alkali-silica reaction, and to a certain percentage of fly ash and lithium hydroxide complex joint effect of inhibiting alkali-silica reaction in the test. The results showed that compound admixtures overcome the shortcomings of the use of fly ash alone or lithium hydroxide inhibition of alkali-silica reaction. It can achieve the goal of complementary advantages.

Poly (Lactic Acid) Generated for Advanced Materials

2017 ◽  
pp. 106-127
Author(s):  
Pranut Potiyaraj
Keyword(s):  
Lactic Acid ◽  
Fossil Fuels ◽  
Raw Materials ◽  
Degradation Mechanism ◽  
Test Methods ◽  
Standard Test ◽  
Advanced Materials ◽  
Poly Lactic Acid ◽  
Plastic Industry ◽  
The Cost

The consumption of plastic products from petrochemical feedstock has increased sharply resulting in plastic waste problems while raw materials from fossil fuels tend to decrease rapidly. Researchers and the plastic industry have since proposed a sustainable solution through the development of bioplastics. Ideally, bioplastics which are synthesized from renewable bioresources normally render biodegradability in appropriate conditions. Polyester, one of the most diversely used synthetic polymers today, is an ideal choice for biodegradable polymers due to the relative ease of breaking ester linkages. Poly(lactic acid) or polylactide or PLA which is a thermoplastic polyester with many advantageous properties, for instance, environmentally friendly, biocompatibility, processability, and high chemical resistance is now available in the plastic market as a promising bioplastics. However, the cost of PLA is still much higher than that of general commodity plastics. In order to make PLA commercially competitive, advanced and innovative applications should thus be explored. In this chapter, technological background of PLA production as well as its economic situation is firstly reviewed. Then, the enhancement of PLA properties to suit advanced applications is illustrated. Some polymers used for blending with PLA along with some fillers utilized for the production of PLA composites are described. The chapter concludes with the degradation mechanism of PLA and the standard test methods.

Status of ASTM and Other National Standards for the Use of Fly Ash Pozzolans in Concrete

1986 ◽  
Vol 86 ◽  
Author(s):  
Richard M. Majko
Keyword(s):  
Fly Ash ◽  
Activity Index ◽  
Hydrated Lime ◽  
Test Methods ◽  
General Purpose ◽  
Standard Test ◽  
Heat Of Hydration ◽  
Pozzolanic Activity ◽  
National Standards ◽  
Sulfate Resistance

ABSTRACTThe Subcommittee of ASTM that is responsible for pozzolan specifications, (C09.03.10) is currently revising C 618, the standard specification, and C 311, the standard test methods. It is no small task. It is generally considered that dividing fly ashes into two classifications (Class F and Class C) is no longer acceptable. The Subcommittee has reached the tentative conclusion that one class of fly ash pozzolan is more appropriate and less ambiguous, provided it is accompanied by an optional table outlining the appropriate limits for sulfate resistance, heat of hydration, hydraulic properties, etc. That is, the engineer need specify only a fly ash pozzolan. If the engineer needs more than a “general purpose” fly ash he calls for special characteristics from the optional requirement table. Any major revision in the C 618 specification challenges the Subcommittee to look for better and more useful test methods in C 311. The committee is looking at C 1012 for a sulfate resistance procedure, conduction calorimetry as a heat of hydration method, and better methods to evaluate pozzolanic activity. The committee is aware of the limited usefulness of hydrated lime or sodium hydroxide in evaluating pozzolanic activity. Perhaps a more suitable term, i.e. the activity index with cement, is more appropriate. Fly ash properties that need to be evaluated include water reduction, activation by lime and alkalies, hydraulic or self-cementing properties and pozzolanic activity. Any test that tends to compensate for a fly ash's lower reactivity (i.e., accelerated thermal curing at 35°C or 65°C) probably leads to misleading results. A critical look at the national standards of other countries might allow the committee to take a visionary yet practical approach toward a new fly ash specification.

scholarly journals Development of Enhanced Test Methods to Evaluate Alkalisilica Reaction in Concrete

2021 ◽  
Author(s):  
Noura Sinno
Keyword(s):  
Preventive Measures ◽  
Test Methods ◽  
Standard Test ◽  
Test Method ◽  
The Other ◽  
Field Conditions ◽  
Alkali Silica Reaction ◽  
Test Duration ◽  
Concrete Prism ◽  
Concrete Prism Test

Many preventive measures showed improved performance of concrete against alkali-silica reaction (ASR) based on the concrete prism test (CPT) described in the Canadian and American Standards, CSA A23.2-14A and ASTM C1293. However, research has shown that preventive measures that limited the 2-year expansion in the concrete prism test produced late expansion after 7-15 years when tested in the field. The objective of this research is to understand the possible reasons for this late expansion under field conditions and to come up with modified approach to determine the level of supplementary cementing materials (SCM) needed to mitigate the long-term expansion. The research mainly focuses on studying two possible reasons to explain the late expansion. The first reason is the rate and ultimate hydration of SCM, where their capacity to bind alkalis under CPT could be higher than those under field conditions. The other reason for the late expansion could be the geometry and size of the CPT samples which might reduce the expansion due to the excessive alkali leaching. Larger samples showed less leaching compared to standard prisms. 100-mm cylinders showed higher expansion than 75-mm standard prisms; however, both sample shapes showed similar expansions for one tested aggregate when used with SCM. In addition, the capacity of SCM to bind alkalis was shown to be higher at 38ºC compared to the other two tested temperatures investigated in this study: 23ºC and 60ºC. Samples with SCM at high replacement levels expanded more at 60ºC compared to 38ºC. Due to their reduced leaching compared to prisms, testing cylinders at 60ºC showed accelerated results reducing the testing duration to one year compared to the standard test duration of two years. Moreover, a new way to predict the minimum levels of SCM required to mitigate expansion due to alkali-silica reaction is presented showing better correlation with the field. Finally, a fast and reliable test method is suggested to evaluate the reactivity of mineral fillers by adapting and adopting the current test methods available for ASR testing.

scholarly journals The appraisal of Testing centre of the JSC “The URIR named after A. S. Berezhnoy” on compliance of the measurement management system with requirements of the ДСТУ ISO 10012:2005

2019 ◽  
Vol 119 ◽  
pp. 122-126
Author(s):  
P. O. Kushchenko ◽  
O. V. Dunikov ◽  
V. V. Varganov
Keyword(s):  
Management System ◽  
Raw Materials ◽  
Thermomechanical Properties ◽  
Test Methods ◽  
Standard Test ◽  
Current Standards

For many years, the refractory and refractory raw materials have been successfully tested at the Testing centre of the JSC “The URIR named after A. S. Berezhnoy” for the orders of manufacturers and consumers of refractory products and for the institute’s own needs. Testing of refractory products is carried out in order to determine the physicochemical, physico­mechanical, thermophysical and thermomechanical properties and assess the quality of refractories and refractory raw materials. When conducting tests of refractories in the Testing centre of institute, standard test methods are used in accordance with the current standards in Ukraine and the methods developed at the institute. In this article, features of the measurement management system in Testing centre of the JSC “The URIR named after A. S. Berezhnoy” and results of the appraisal of Testing centre of the institute are adduced.

scholarly journals Development of Enhanced Test Methods to Evaluate Alkalisilica Reaction in Concrete

2021 ◽  
Author(s):  
Noura Sinno
Keyword(s):  
Preventive Measures ◽  
Test Methods ◽  
Standard Test ◽  
Test Method ◽  
The Other ◽  
Field Conditions ◽  
Alkali Silica Reaction ◽  
Test Duration ◽  
Concrete Prism ◽  
Concrete Prism Test

Many preventive measures showed improved performance of concrete against alkali-silica reaction (ASR) based on the concrete prism test (CPT) described in the Canadian and American Standards, CSA A23.2-14A and ASTM C1293. However, research has shown that preventive measures that limited the 2-year expansion in the concrete prism test produced late expansion after 7-15 years when tested in the field. The objective of this research is to understand the possible reasons for this late expansion under field conditions and to come up with modified approach to determine the level of supplementary cementing materials (SCM) needed to mitigate the long-term expansion. The research mainly focuses on studying two possible reasons to explain the late expansion. The first reason is the rate and ultimate hydration of SCM, where their capacity to bind alkalis under CPT could be higher than those under field conditions. The other reason for the late expansion could be the geometry and size of the CPT samples which might reduce the expansion due to the excessive alkali leaching. Larger samples showed less leaching compared to standard prisms. 100-mm cylinders showed higher expansion than 75-mm standard prisms; however, both sample shapes showed similar expansions for one tested aggregate when used with SCM. In addition, the capacity of SCM to bind alkalis was shown to be higher at 38ºC compared to the other two tested temperatures investigated in this study: 23ºC and 60ºC. Samples with SCM at high replacement levels expanded more at 60ºC compared to 38ºC. Due to their reduced leaching compared to prisms, testing cylinders at 60ºC showed accelerated results reducing the testing duration to one year compared to the standard test duration of two years. Moreover, a new way to predict the minimum levels of SCM required to mitigate expansion due to alkali-silica reaction is presented showing better correlation with the field. Finally, a fast and reliable test method is suggested to evaluate the reactivity of mineral fillers by adapting and adopting the current test methods available for ASR testing.

Comparison of short- and long-term ASR test methods on cementitious composites

2020 ◽  
Vol 6 (2) ◽  
pp. 68
Author(s):  
Burak Sivrikaya ◽  
İlhami Demir ◽  
Özer Sevim
Keyword(s):  
Fly Ash ◽  
Material Selection ◽  
Water Solution ◽  
Test Methods ◽  
Test Method ◽  
Alkali Silica Reaction ◽  
Naoh Solution ◽  
Short And Long Term ◽  
Physical And Chemical

Concrete has a significant place in construction structures, is a material that can be easily damaged due to incorrect design, incorrect material selection. Concrete may be damaged by physical and chemical factors. One of these factors is the alkali-silica reaction (ASR). ASTM C1260, is a short-term test method, and ASTM C227, is a long-term test method, are used to measure effect of alkali-silica reaction. In this study, the effect of fly ash additive use with 0, 5, 10, 15, and 20 wt.% replacement of cement was investigated in short- and long-term ASR test methods. For this purpose, while samples prepared for ASTM C1260 were kept in NaOH solution 14-days, samples prepared for ASTM C227 were waited 360-days in normal water solution. As a result; mortar bars with 20% fly ash additive ratio were classified as harmless for ASR in both test methods.

Late Woodland Period Settlement Patterns in the Piedmont Uplands of Pennsylvania: The Evidence from 36CH161

1994 ◽  
Vol 14 (3) ◽  
pp. 245-285
Author(s):  
Paul A. Raber
Keyword(s):  
Raw Materials ◽  
Late Woodland ◽  
Woodland Period ◽  
Late Woodland Period ◽  
Chester County ◽  
Non Local ◽  
Primary Focus ◽  
A Site ◽  
Local Materials ◽  
Early Late

Investigations at 36Ch161, a site in the Piedmont Uplands of Chester County, Pennsylvania, have revealed a series of early Late Woodland Period camps associated with the Minguannan Complex. The use of local quartz seems to have been a primary focus of settlement at the site. Quartz, which formed an overwhelming majority of the assemblage, was used in ways that contrast strongly with that of non-local materials like jasper, a minority component of the assemblage obtained from quarries in the Hardyston Formation. The selection of raw materials suggests restrictions on access to certain materials perhaps imposed by territorial constraints. The combined evidence of artifact assemblage and cultural features indicates that 36Ch161 was inhabited seasonally by small, mobile groups of non-horticulturalists, a reconstruction consistent with that of Custer and others regarding the economy of the Minguannan Complex and related cultures of the Piedmont Uplands.

scholarly journals Facile Preparation of Mesoporous MCM-48 Containing Silver Nanoparticles with Fly Ash as Raw Materials for CO Catalytic Oxidation

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 841
Author(s):  
Dong Tian ◽  
Yonghong Chen ◽  
Xiaoyong Lu ◽  
Yihan Ling ◽  
Bin Lin
Keyword(s):  
Silver Nanoparticles ◽  
Fly Ash ◽  
Co Oxidation ◽  
Surface Composition ◽  
Raw Materials ◽  
Silica Source ◽  
Co Conversion ◽  
Co Catalytic Oxidation ◽  
Adsorption Desorption

An environmentally friendly method was proposed to prepare mesoporous Mobil Composition of Matter No.48 (MCM-48) using fly ash as the silica source. Silver nanoparticles were infiltrated on MCM-48 facilely by an in situ post-reduction method and evaluated as an effective catalyst for CO oxidation. The as-prepared MCM-48 and Ag/MCM-48 nanoparticles were characterized by XRD, N2 adsorption/desorption, and TEM. Investigations by means of XPS for Ag/MCM-48 were performed in order to illuminate the surface composition of the samples. Studies revealed the strong influence of the loading of Ag nanoparticles on catalysts in the oxidation of CO. CO conversion values for Ag/MCM-48 of 10% and 100% were achieved at temperatures of 220 °C and 270 °C, respectively, indicating that the Ag-decorated MCM-48 catalyst is extremely active for CO oxidation.

scholarly journals Comparison of Two Intergranular Corrosion Tests on EN AW-6016 Sheet Material

2021 ◽  
Vol 11 (11) ◽  
pp. 5294
Author(s):  
Peer Decker ◽  
Ines Zerbin ◽  
Luisa Marzoli ◽  
Marcel Rosefort
Keyword(s):  
Optical Microscopy ◽  
Intergranular Corrosion ◽  
Sheet Material ◽  
Test Methods ◽  
Standard Test ◽  
Corrosion Depth ◽  
Corrosion Tests ◽  
Automotive Company ◽  
Test Parameters

Two different intergranular corrosion tests were performed on EN AW-6016 sheet material, an ISO 11846:1995-based test with varying solution amounts and acid concentrations, and a standard test of an automotive company (PV1113, VW-Audi). The average intergranular corrosion depth was determined via optical microscopy. The differences in the intergranular corrosion depths were then discussed with regard to the applicability and quality of the two different test methods. The influence of varying test parameters for ISO 11846:1995 was discussed as well. The determined IGC depths were found to be strongly dependent on the testing parameters, which will therefore have a pronounced influence on the determined IGC susceptibility of a material. In general, ISO 11846:1995 tests resulted in a significantly lower corrosion speed, and the corrosive attack was found to be primarily along grain boundaries.

Sign in / Sign up

Export Citation Format

Share Document