<rss version="2.0" xmlns:atom="https://www.w3.org/2005/Atom">
  <channel>
    <title>Transport Research International Documentation (TRID)</title>
    <link>https://trid.trb.org/</link>
    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
    <description></description>
    <language>en-us</language>
    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
    <docs>http://blogs.law.harvard.edu/tech/rss</docs>
    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
    <image>
      <title>Transport Research International Documentation (TRID)</title>
      <url>https://trid.trb.org/Images/PageHeader-wTitle.jpg</url>
      <link>https://trid.trb.org/</link>
    </image>
    <item>
      <title>Investigation of High-Range Water Reducers on Inducing Micro-Cracking in Precast Concrete Elements</title>
      <link>https://trid.trb.org/View/1573429</link>
      <description><![CDATA[An overarching objective of this project is to increase the understanding of the effect of polycarboxylate (PC) high-range water-reducers (HRWR) on the performance of concrete mixtures, with a special focus on concrete mixtures that will be used in precast concrete beam applications. The motivation for this research was based upon the results of Interagency Contract (IAC) No. 463MTIA034: Evaluation of Long-Term Durability of Concrete, which addresses potential mechanisms for unexplained cracking in girders cast at Texas precast plants, typically appearing 18–24 months after casting.]]></description>
      <pubDate>Mon, 17 Dec 2018 12:19:01 GMT</pubDate>
      <guid>https://trid.trb.org/View/1573429</guid>
    </item>
    <item>
      <title>Effects of saturated lightweight sand content on key characteristics of ultra-high-performance concrete</title>
      <link>https://trid.trb.org/View/1483153</link>
      <description><![CDATA[In this study, 0 to 75% volume of river sand was replaced by an equivalent amount of pre-saturated lightweight sand (LWS) to enhance mechanical properties and reduce autogenous shrinkage of ultra-high-performance concrete (UHPC). The use of LWS is demonstrated to effectively decelerate and reduce the drop in internal relative humidity and autogenous shrinkage of UHPC. Isothermal calorimetry and thermal gravimetry results showed that the use of LWS promoted cement hydration degree after 28 d of hydration. Mercury intrusion porosimetry and scanning electron microscope analyses revealed that the porosity was decreased and interface properties between sand and cement matrix is enhanced by use of LWS up to 25%. The optimum replacement ratio of LWS to river sand was found to be 25%, which resulted in the highest compressive strength (168 MPa at 91 d), flexural strength (24 MPa at 28 d), and autogenous shrinkage limited to 365 µm/m at 28 d.]]></description>
      <pubDate>Sun, 24 Sep 2017 16:17:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/1483153</guid>
    </item>
    <item>
      <title>Evaluation of precast bridge girder cracking: The role of volume change</title>
      <link>https://trid.trb.org/View/1483154</link>
      <description><![CDATA[In order to better understand the potential impact of volume changes on precast girder cracking, a comprehensive study that evaluated the influence of various materials and mixture proportions on autogenous and drying shrinkage was performed. A subset of the mixtures was assessed using a restrained shrinkage frame, where the stress development was monitored along with the development of mechanical properties. The laboratory investigations were complemented by large scale exposure blocks that were stored outdoors in Austin, TX.]]></description>
      <pubDate>Sun, 24 Sep 2017 16:17:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/1483154</guid>
    </item>
    <item>
      <title>Effects of novel polymer-type shrinkage-reducing admixture on early age autogenous deformation of cement pastes</title>
      <link>https://trid.trb.org/View/1481094</link>
      <description><![CDATA[This study aims to investigate the autogenous shrinkage-reducing mechanisms of the novel polymer-type shrinkage-reducing admixture (SRA) with water-reducing function. For comparison, the traditional polyether-type SRA was also used. The development of autogenous deformation, hydration rate, internal relative humidity (RH), electrical resistivity, ions and SRAs concentration in pore solutions and crystal content of cement pastes were comprehensively investigated. Unlike the polyether-type SRA mixture which has an expansion period at early age, a relatively slow and monotonous evolution of shrinkage was observed for the polymer-type SRA mixture. It is concluded that the delay and regulation effects on cement hydration of the novel SRA obviously influence the microstructure development and the evolutions of various performances of cement pastes comparing to the polyether-type SRA. Furthermore, both the self-desiccation status induced capillary pressure and the crystallization pressure induced expansion stress contribute to the shrinkage-reducing behaviors of SRAs on the autogenous deformation of the cement pastes.]]></description>
      <pubDate>Mon, 04 Sep 2017 12:30:08 GMT</pubDate>
      <guid>https://trid.trb.org/View/1481094</guid>
    </item>
    <item>
      <title>Examining the “time-zero” of autogenous shrinkage in high/ultra-high performance cement pastes</title>
      <link>https://trid.trb.org/View/1466951</link>
      <description><![CDATA[The term “Time-zero”, i.e., the time for the start of autogenous shrinkage measurement, is usually used for estimating the cracking potential of structural components. Accurate determination of the “time-zero” is therefore critical for autogenous shrinkage measurement, which is the main objective of this study. There is a general agreement about the existence of a relationship between autogenous shrinkage and relative humidity (RH) changes in hardening cement paste. An improved hygrometer method was developed for monitoring the change of internal RH in cement pastes 1 h after casting. This provides immediate experimental results of RH change for determining the “time-zero”. It indicates that the internal RH of cement pastes does not decrease immediately after the final setting time. A new “time-zero” is defined as the onset of internal RH drop, which is more reasonable for estimating the cracking potential of cement-based materials, compared to the “time-zero” represented by the final setting time.]]></description>
      <pubDate>Mon, 05 Jun 2017 18:05:23 GMT</pubDate>
      <guid>https://trid.trb.org/View/1466951</guid>
    </item>
    <item>
      <title>Internal curing of high performance concrete using cenospheres</title>
      <link>https://trid.trb.org/View/1464206</link>
      <description><![CDATA[This study explores a novel internal curing agent, perforated cenospheres. Cenospheres are hollow fly ash particles produced from coal burning power plants. The shell of the cenospheres is inherently porous that is sealed by a thin layer of glass-crystalline film. By removing this film through chemical etching, the pores on the shell can be exposed, perforating the cenospheres and providing paths for water propagating into the internal volume of cenospheres. The perforated cenosphere were found to have water absorption as high as 180 wt%. The loaded water can be readily released from the cenospheres under high relative humidity (95%). When incorporating saturated cenospheres into cement mortar for internal curing, the autogenous shrinkage of the mortar was almost eliminated. The internal curing also improved the compressive strength of the cement mortar. All these results suggest that perforated cenospheres can be used as an efficient internal curing agent for high performance concrete (HPC).]]></description>
      <pubDate>Mon, 15 May 2017 15:16:49 GMT</pubDate>
      <guid>https://trid.trb.org/View/1464206</guid>
    </item>
    <item>
      <title>Development of Test Methods to Identify Shrinkage Properties of Cementitiously Stabilized Materials</title>
      <link>https://trid.trb.org/View/1439272</link>
      <description><![CDATA[Shrinkage cracking of the cementitiously stabilized layers (CSL) causes distress to pavement structure and influences its service life. Shrinkage of CSL can be categorized into free drying shrinkage, autogenous shrinkage, and thermal shrinkage. This study developed new test methods to identity the shrinkage properties of cementitiously stabilized materials (CSM), including free drying shrinkage, autogenous shrinkage, and coefficient of thermal expansion (COTE). The test methods were first evaluated in the laboratory on both heavily and lightly stabilized materials and were found to be effective. Results also showed that autogenous shrinkage strain is small compared with drying and thermal ones. In addition, free drying shrinkage and COTE tests were conducted on other types of CSM under various environmental conditions. The results of the drying shrinkage tests, which considered the influence of temperature and humidity, were used to develop a shrinkage strain model. The new model is shown to predict well the drying shrinkage strain of early-age CSM.]]></description>
      <pubDate>Sun, 26 Mar 2017 17:39:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/1439272</guid>
    </item>
    <item>
      <title>Influence of Fine Particles on Strength and Autogenous Shrinkage of Alkali-Activated Slag Pastes</title>
      <link>https://trid.trb.org/View/1439029</link>
      <description><![CDATA[Concrete industry has explored various options to reduce the usage of ordinary portland cement (OPC) in concrete by finding suitable replacement materials. Alkali activation of alumino-silicate materials as cement free binders for concrete is a promising alternative to the use of portland cement. The objective of the present study was to determine the role of different types of fine particles on the compressive strength, workability, setting time, reaction kinetics and autogenous shrinkage of the alkali activated slag cement. Sodium silicate and sodium hydroxide were used as the alkaline solutions for activating the slag cement. Nano silica, kaolinite clay and slightly modified kaolinite clay, referred to as coated clay, were used as the fine particles. The amount of fine particle used was 1% and 2% of the binder mass. Reaction kinetic of the pastes was evaluated using an in-situ isothermal conduction calorimetry. The fine particle addition significantly increased the compressive strength of the sodium silicate activated slag cement. Whereas, the workability, setting time and autogenous shrinkages were significantly reduced due to fine particle addition in the sodium silicate activated slag system. An entirely different behavior was obtained when the fine particles were added to a sodium hydroxide activated slag system. The compressive strength and autogenous shrinkage were not significantly affected by the fine particle addition in the sodium hydroxide activated slag. Nano silica was the most reactive fine particle irrespective of the type of activator used.]]></description>
      <pubDate>Mon, 13 Mar 2017 16:05:41 GMT</pubDate>
      <guid>https://trid.trb.org/View/1439029</guid>
    </item>
    <item>
      <title>Bridge Decks: Mitigation of Cracking and Increased Durability</title>
      <link>https://trid.trb.org/View/1429406</link>
      <description><![CDATA[The application of pre-soaked lightweight aggregates (LWA) as an internal curing agent in concrete to reduce the cracking due to drying shrinkage is thoroughly studied in this report. It is determined that although LWA can significantly reduce autogenous shrinkage, its effect on drying shrinkage is minimal and in some cases it can even increase the drying shrinkage. Moreover, the combined effects of LWA and expansive cement (Type K) and LWA and shrinkage-reducing admixtures (SRAs) on drying shrinkage is also studied. It is shown that addition of Type K cement or SRA to mixtures containing LWA can significantly reduce drying shrinkage and make the mixture more volumetrically stable.]]></description>
      <pubDate>Tue, 15 Nov 2016 11:34:39 GMT</pubDate>
      <guid>https://trid.trb.org/View/1429406</guid>
    </item>
    <item>
      <title>A coupled thermo-hygro-chemical model for characterising autogenous healing in ordinary cementitious materials</title>
      <link>https://trid.trb.org/View/1419995</link>
      <description><![CDATA[Experimental work has demonstrated that cracks can be healed in ordinary cementitious materials in the presence of water. The primary healing mechanisms are hydration of the unreacted nuclei of cement particles and the long-term formation of calcite. A mathematical model for simulating early-age autogenous healing of ordinary cement-based materials is proposed, which employs a coupled thermo-hygro-chemical (THC) framework and which uses a reactive water transport component to predict the movement of healing materials. A single concentration variable is employed for the healing component of the model that is derived directly from the quantity of unreacted cement and computed using a generalised cement hydration model component. The hydration component is directly linked to an expression for capillary porosity and for the porosity of the material within a healed crack. The results from a series of model simulations are in good general agreement with experimental data from tests on autogenous healing.]]></description>
      <pubDate>Sun, 04 Sep 2016 18:47:28 GMT</pubDate>
      <guid>https://trid.trb.org/View/1419995</guid>
    </item>
    <item>
      <title>Modelling of autogenous healing in ultra high performance concrete</title>
      <link>https://trid.trb.org/View/1375979</link>
      <description><![CDATA[The restoration of ultra high performance concrete (UHPC) specimens due to the self-healing phenomenon was investigated in this paper. A hydro-chemo-mechanical model based on micro-mechanical observations was established. The aim was to evaluate the mechanical properties of the new healing products in order to describe the partial recovery of the mechanical properties of healed concrete. An analysis of the influence of some physical parameters provided first explanations about the self-healing phenomenon. It was shown that the mechanical properties of calcium silicate hydrate (CSH) in the healed crack are lower than the ones of the virgin material.]]></description>
      <pubDate>Tue, 08 Dec 2015 16:09:17 GMT</pubDate>
      <guid>https://trid.trb.org/View/1375979</guid>
    </item>
    <item>
      <title>Autogenous healing of marine exposed concrete: Characterization and quantification through visual crack closure</title>
      <link>https://trid.trb.org/View/1362044</link>
      <description><![CDATA[Concrete can autogenously heal cracks potentially increasing construction durability. Studies quantifying this process are limited to fresh-water, making the controlling parameters in sea-water unclear. Here the authors visually quantify the autogenous healing capacity of ordinary Portland cement (OPC) and blast-furnace slag (BFS) cement mortar specimens submerged in fresh- and sea-water. After 56 days, BFS cement specimens in sea-water healed 100% of cracks up to 104 µm, while for OPC specimens it was 592 µm. In fresh-water, BFS cement specimens healed 100% of cracks up to 408 µm, while OPC specimens healed 100% of cracks up to 168 µm. Displaying greater healing efficiency OPC specimens in sea-water became weak, developing unacceptable losses in compressive strength. Differences in performance were attributed to the amount of calcium hydroxide in these mortars and specific ions present in sea-water. Visual crack-healing, therefore, should be assessed in conjunction with a material functional property.]]></description>
      <pubDate>Tue, 25 Aug 2015 21:44:27 GMT</pubDate>
      <guid>https://trid.trb.org/View/1362044</guid>
    </item>
    <item>
      <title>The influence of superabsorbent polymers on the autogenous shrinkage properties of cement pastes with supplementary cementitious materials</title>
      <link>https://trid.trb.org/View/1362072</link>
      <description><![CDATA[Fly ash and blast-furnace slag containing binders are frequently used in the construction industry and it is important to know the extent of autogenous shrinkage and its (ideal) mitigation by superabsorbent polymers in these systems as a function of their age. In this paper, the autogenous shrinkage was determined by manual and automated shrinkage measurements. Autogenous shrinkage was reduced in cement pastes with the supplementary cementitious materials versus Portland cement pastes. At later ages, the rate of autogenous shrinkage is higher due to the pozzolanic activity. Internal curing by means of superabsorbent polymers is successful, independent of this long term higher rate of shrinkage in mixtures with supplementary cementitious materials.]]></description>
      <pubDate>Tue, 25 Aug 2015 21:44:05 GMT</pubDate>
      <guid>https://trid.trb.org/View/1362072</guid>
    </item>
    <item>
      <title>Internal curing by superabsorbent polymers in ultra-high performance concrete</title>
      <link>https://trid.trb.org/View/1363466</link>
      <description><![CDATA[To limit self-desiccation and autogenous shrinkage that may lead to early-age cracking of ultra-high performance concrete (UHPC), internal curing by means of superabsorbent polymers (SAP) may be employed. Cement pastes and UHPC with water-to-cement ratio below 0.25, with or without SAP, were studied. The absorption capacity of a solution-polymerized SAP was first determined on hardened cement pastes by scanning electron microscopy (SEM) image analysis. It was observed that the SAP cavities become partially filled with portlandite during cement hydration. Isothermal calorimetry showed that water entrainment with SAP delays the main hydration peak, while after a couple of days it increases the degree of hydration in a manner similar to increasing the water-to-cement ratio. Internal curing by SAP is effective in reducing the internal relative humidity decrease and the autogenous shrinkage. Although the mechanical properties are affected by SAP addition, it is possible to reach compressive strengths of almost 150 MPa at 28 days.]]></description>
      <pubDate>Tue, 25 Aug 2015 21:43:58 GMT</pubDate>
      <guid>https://trid.trb.org/View/1363466</guid>
    </item>
    <item>
      <title>EFFECTS OF AGGREGATE PARTICLES ON SPATIAL DISTRIBUTION OF SUPERABSORBENT POLYMERS FOR INTERNAL CURING</title>
      <link>https://trid.trb.org/View/1351592</link>
      <description><![CDATA[One of the effective methods to reduce autogenous shrinkage is internal curing, which uses superabsorbent polymer（SAP）as a water reservoir. In designing a mix proportion of concrete containing the internal water reservoir, an amount of water to prevent reduction of relative humidity is taken into account. However, effectiveness of the internal curing depends on not only the amount of the internal water but also its spatial distribution since the water must travel within a dense cement paste matrix. Therefore, distribution of SAP particles may be an important parameter to control efficiency of the internal water curing. In this study, spatial distribution of SAP particles in mortars was evaluated by some functions of point process statistics. The concept of the thinned point process was applied to the distributions of SAP in cement paste and mortar specimens. The null hypothesis was that the locations of SAP particles in mortar were determined solely on π（x）-thinning for cement paste phase. As expected, distribution of SAP particles in cement paste specimens was almost random so that its dispersion could be regarded as a Poisson process. On the other hand, distribution of SAP in mortar was a clustering pattern because the presence of aggregate particles controlled locations of SAP particles. However, its clustering patterns were different from those obtained as a point process thinned from an original random pattern in the corresponding cement paste. Furthermore, the clustering tendency was dependent on the size of SAP particles used for internal curing. This means that aggregate has a certain effect to promote clustering besides to random thinning of SAP particles.内部養生材として使用される超吸水性ポリマー（SAP）の空間分布を点過程統計量によって定量的に評価した。その結果、セメントペースト供試体中のSAP粒子は粒径にかかわらずほぼランダムな分布であるのに対して、モルタル供試体中では凝集性を有した配置となった。凝集性を示す距離範囲はSAPの粒径によって異なり、小径のSAPの方がより近距離で凝集性が現れる。また、この凝集性により定常ポアッソン過程という帰無仮説は棄却されることがシミュレーションにより示された。これより、骨材粒子の存在はSAP粒子の分布を単純にランダムに制限する以上の効果を持つと考えられる。]]></description>
      <pubDate>Mon, 27 Apr 2015 09:48:59 GMT</pubDate>
      <guid>https://trid.trb.org/View/1351592</guid>
    </item>
  </channel>
</rss>