The effectiveness of membrane curing compounds for portland cement concrete pavements


Book Description

Membrane curing compounds are widely used to cure concrete in highway construction. The function of these compounds is to form a membrane that helps retain moisture in the concrete slab, otherwise lost through evaporation. The amount of evaporation loss varies as a function of the environmental conditions and the temperature of the concrete mass during the curing period. This rpeort provides an evaluation of the performance of membrane curing compounds as related to concrete material properties such as tensile and flexural strength, stiffness, surface durability, and density. In addition to traditional testing methods, the non-destructive, in-situ, Spectral Analysis of Surface Waves method is also used to observe and measure material properties as a function of time. Testing can start at initial set or when the modulus of elasticity for concrete is about 10,000 psi.
















Effectiveness of Membrane-Forming Curing Compounds for Curing Concrete


Book Description

A search was made for test methods to evaluate the effectiveness of curing concrete. Test methods that include water absorptivity (proposed ASTM test), capillary porosity, combined water, splitting tensile strength, and abrasion resistance were evaluated. Curing compounds having a wide range of water retention values and meeting the requirements of ASTM C 309-89 and CRD-C 300 were obtained for evaluation. A few curing compounds were prepared in the laboratory by diluting one of the CRD-C 300 curing compounds with the vehicle solvent furnished by the manufacturer to obtain curing compounds that would not meet the requirements of either specification. The water-absorptivity test and an abrasion test developed in the laboratory were used to determine the effectiveness of the different curing compounds for curing concrete. Curing compounds meeting the requirements of ASTM-C 309-89 were found to be as effective as curing compounds meeting the requirements of CRD-C 300 for curing concrete. Two of the curing compounds that did not meet the specification requirements were also found to be effective based on the water-absorptivity test method. The abrasion test shows promise as a test method for evaluating the effectiveness of curing and is less time consuming than the water-absorptivity test method. Keywords: Abrasion, Construction materials, Absorptivity, Membrane-forming curing compounds, Moisture retention, Portland cement concrete, Portland cement mortar. (JG).




An Introduction to Advanced Issues in Curing Portland Cement Concrete Pavement


Book Description

Technical guidance for civil engineers and others interested in advanced technology issues regarding curing portland cement concrete pavement for streets and highways. Here is what is discussed: 1. INTRODUCTION 2. BLEEDING RATE—EVAPORATION RATE RELATIONSHIP 3. EFFECTIVENESS OF EVAPORATION REDUCERS 4. TIME OF CURING COMPOUND APPLICATION 5. WATER-RETENTION REQUIREMENTS FOR CURING COMPOUNDS 6. VARIABILITY IN TEST METHOD FOR WATER RETENTION OF CURING COMPOUNDS—ASTM C 156 7. APPLICATION RATE OF CURING COMPOUNDS 8. RECOVERY FROM POOR OR LATE APPLICATION OF CURING COMPOUND 9. EFFECT OF CLIMATIC CONDITIONS ON CURING COMPOUND DRYING TIME 10. APPLICATION OF CURING COMPOUND TO TINED SURFACES—EFFECT OF SAGGING 11. TEST METHODS FOR MEASURING CURING COMPOUND APPLICATION 12. LENGTH OF CURING 13. TEST METHODS FOR MEASURING CURING EFFECTIVENESS 14. THERMAL STRESS DUE TO EVAPORATIVE COOLING 15. CONCLUSIONS AND RECOMMENDATIONS.




An Introduction to Advanced Issues in Curing Portland Cement Concrete Pavement


Book Description

Technical guidance for civil engineers and others interested in advanced technology issues regarding curing portland cement concrete pavement for streets and highways. Here is what is discussed:1. INTRODUCTION2. BLEEDING RATE-EVAPORATION RATE RELATIONSHIP3. EFFECTIVENESS OF EVAPORATION REDUCERS4. TIME OF CURING COMPOUND APPLICATION5. WATER-RETENTION REQUIREMENTS FOR CURING COMPOUNDS6. VARIABILITY IN TEST METHOD FOR WATER RETENTION OF CURING COMPOUNDS-ASTM C 1567. APPLICATION RATE OF CURING COMPOUNDS8. RECOVERY FROM POOR OR LATE APPLICATION OF CURING COMPOUND9. EFFECT OF CLIMATIC CONDITIONS ON CURING COMPOUND DRYING TIME10. APPLICATION OF CURING COMPOUND TO TINED SURFACES-EFFECT OF SAGGING11. TEST METHODS FOR MEASURING CURING COMPOUND APPLICATION12. LENGTH OF CURING13. TEST METHODS FOR MEASURING CURING EFFECTIVENESS14. THERMAL STRESS DUE TO EVAPORATIVE COOLING15. CONCLUSIONS AND RECOMMENDATIONS.