Deterioration has been observed at the joints of many portland cement–based concrete pavements in midwestern U.S. states. It has been shown that this damage can be caused by either classic freeze–thaw behavior triggered by high saturation levels or a chemical reaction that occurs between the deicing salt (in this study, calcium chloride) and the cementitious matrix. The objective of this study was to show that low-temperature differential scanning calorimetry could be used to quantify the potential for the chemical reaction between the salt and matrix (i.e., calcium oxychloride formation). The formation of calcium oxychloride is expansive and may lead to significant cracking and spalling without exposure to freeze–thaw cycles. This study examined pastes made with ordinary portland cement; portland limestone cement; and portland cement combined with fly ash, slag, or silica fume. The results indicate that the amount of calcium oxychloride formation that occurs is not significantly different between ordinary portland cements and portland limestone cements. The addition of supplementary cementitious materials reduces the formation of the calcium oxychloride, presumably because of the reduction of calcium hydroxide from dilution, the pozzolanic reaction, and a reduction in the alkali content in the pore solution. The results also indicate that sealers can be used to create a barrier between the salt and the calcium hydroxide or that they can react with the calcium hydroxide, thereby reducing the amount of calcium oxychloride.

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Whereas many concrete pavements have exhibited service lives of 30 to 50 years, a portion of these pavements in regions that are exposed to snow, ice, and salt have shown premature distress at the joints. This distress has been observed to occur between 5 and 20 years and requires extensive repair of an otherwise well-functioning pavement. Although there are several potential mechanisms that can lead to this deterioration, a reaction can occur between calcium chloride coming from deicing salt (CaCl2) and the tricalcium aluminate (C3A) and/or calcium hydroxide (CH) in the cementitious matrix. This paper describes the development of a test method that can be used to evaluate the potential for a cementitious binder to react with the calcium chloride deicing salts to form calcium oxychloride (the reaction between CaCl2 and CH). The test method enables the quantity of calcium oxychloride to be determined for each binder system. The results indicate that the amount of calcium oxychloride can be reduced with the replacement of cement with supplementary cementitious materials (fly ash, slag, silica fume, etc.). It is anticipated that the proposed test method could be used to better understand the role of binder chemistry on the calcium oxide formation and to optimize the binder composition to reduce the calcium chloride formation to an acceptable level and ultimately reduce the risk for deterioration.

Findings• Some concrete pavements have shown premature deterioration at the joints. It has been proposed that this can be attributed to two primary factors: increased fl uid saturation and a chemical reaction that occurs between deicing salts and the cement matrix.• A test method was developed/formalized that uses a low temperature diff erential scanning calorimeter (LTDSC) test method to quantify the chemical reaction that occurs between the cementitious matrix and the deicing salt to form calcium oxychloride.• It is proposed that the LTDSC test be used to qualify the potential for calcium oxychloride formation in a cementitious matrix. Currently two primary JOINT TRANSPORTATION RESEARCH PROGRAM

Many of the buildings which experienced damage in recent earthquakes such as the 2015 Nepal Earthquake were reinforced concrete (RC) frame buildings with unreinforced masonry infill walls. This study proposes a simplified procedure to estimate the in-plane seismic capacity of masonry infilled RC frame buildings based on concepts of the Japanese seismic evaluation standard (JBDPA, [1]). The correlation of seismic capacity and observed damage obtained using a database of 370 existing RC frame buildings with masonry infill that experienced earthquakes in Taiwan, Ecuador and Nepal is investigated. The Is index, which represents the seismic capacity of buildings in the Japanese standard, showed good correlation with the observed damage and proved to be effective as a simple method to estimate seismic capacity. The method was then applied to 103 existing buildings in Bangladesh that have not experienced a major earthquake recently. The results emphasize the necessity for urgent seismic evaluation and retrofitting of buildings in Bangladesh.