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International Concrete Abstracts Portal

Showing 1-5 of 8 Abstracts search results

Document: 

SP282

Date: 

December 29, 2011

Author(s):

Editor: Charles A. Weiss, Jr.

Publication:

Symposium Papers

Volume:

282

Abstract:

SP-282 This CD-ROM contains seven papers that were presented at sessions sponsored by ACI Committee 522 at the ACI Fall 2009 Convention in New Orleans, LA. The aim of this SP is to present some of the latest research findings on pervious concrete and to provide state-of-the-art examples on the use of pervious concrete. The six papers in this SP present the latest research results from both experimental and numerical studies on various aspects of pervious concrete.

DOI:

10.14359/51683563


Document: 

SP282-02

Date: 

December 27, 2011

Author(s):

Norbert Delatte

Publication:

Symposium Papers

Volume:

282

Abstract:

Portland Cement Pervious Concrete (PCPC) is a material of increasing interest for parking lots and other applications. PCPC typically consists of coarse aggregates, portland cement, water, and various admixtures. In this research, in-service PCPC pavements were inspected in the field, and cores were removed in order to investigate properties in the laboratory. Field evaluation methods included visual inspection, two surface drainage measurements, and indirect transmission ultrasonic pulse velocity (UPV). Laboratory testing methods included void ratio, unit weight, compressive strength, splitting tensile strength, hydraulic conductivity, and direct transmission UPV. Because it is compacted on the surface with screeds or rollers, PCPC generally has higher strength, lower void ratio, and lower hydraulic conductivity at the surface than at the bottom. Therefore, the properties of the tops and bottoms of core samples were compared. Generally, the PCPC installations evaluated under this research project have performed well in freeze-thaw environments with little maintenance required. No visual indicators of freeze-thaw damage were observed. With the exception of some installations where the pore structure was sealed during construction with wet mixtures or over compaction, nearly all sites showed fair to good infiltration capability based on drain time measurements.

DOI:

10.14359/51683639


Document: 

SP282-03

Date: 

December 27, 2011

Author(s):

Jonathan Thomle and Liv Haselbach

Publication:

Symposium Papers

Volume:

282

Abstract:

The focus of this study is on the pH changes over time of water in contact with pervious concrete aged under varying ambient air restrictions. Elevated pH levels may be a concern if exfiltrated directly to sensitive waters. This study was conducted to aid designers by determining the rate of pH decline under various conditions. For this study laboratory prepared pervious concrete specimens exposed to three different levels of ambient air were periodically tested for pH using four different testing methods, infiltrating either deionized water or tap water through the specimens, or soaking the specimens in either deionized water or tap water. Obvious trends in pH decline were observed. Greater exposure to ambient air significantly increased the rate of pH decline. The tap water tests represented more typical stormwaters and had much lower pH readings than the deionized water tests. The samples were representative of typical in-place conditions in an arid environment with little buffering and yet the pH declined sufficiently in well under a year.

DOI:

10.14359/51683640


Document: 

SP282-06

Date: 

December 27, 2011

Author(s):

Matt Offenberg

Publication:

Symposium Papers

Volume:

282

Abstract:

One of the key concerns with pervious concrete is the material’s surface durability, specifically resistance to raveling. As the market for pervious concrete grew, this was one of the hurdles to broader adoption of the technology. This paper documents the process of developing a test method to determine the potential raveling resistance of a pervious concrete mixture. The process included a study with lab cast cylinders to compare the raveling resistance potential of pervious concrete mixtures using different aggregates, varying cement contents, and basic chemical admixtures. A refined procedure of the test method was developed after an unsuccessful ASTM round robin evaluation. The results from this new method will provide the industry with beginning correlations between basic mix ingredients and the surface durability of a finished pervious concrete pavement.

DOI:

10.14359/51683643


Document: 

SP282-07

Date: 

December 27, 2011

Author(s):

Zhifu Yang

Publication:

Symposium Papers

Volume:

282

Abstract:

Frost damage can be a significant problem for pervious concrete structures in the cold climate. Various damage mechanisms have been developed to explain the frost damage in conventional concretes. However, limited studies have been attempted to correlate these mechanisms with pervious concretes. This paper reviews the physical aspects of frost damage and the main factors (e.g. the degree of saturation, the permeability of paste, the length of flow path, and the rate of freezing) that contribute to the deterioration of concrete upon freezing with the goal of using these mechanisms to explain the experimental observations obtained from the pervious concrete. This paper also compares the differences in freeze and thaw deterioration between pervious and conventional concretes. A variety of test results from different pervious concrete mixtures and construction practices are analyzed, which would aide in identifying the optimal mixture design and construction procedures to achieve durable pervious concrete structures.

DOI:

10.14359/51683644


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