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    <title>Transport Research International Documentation (TRID)</title>
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    <atom:link href="https://trid.trb.org/Record/RSS?s=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" rel="self" type="application/rss+xml" />
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    <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>
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    <item>
      <title>Durability of Rapid-Setting Concrete Repairs on Pavement Panels and Bridge Decks in Utah</title>
      <link>https://trid.trb.org/View/2719342</link>
      <description><![CDATA[The objective of this research was to evaluate the durability of rapid-setting concrete batched using volumetric concrete mixers and placed in a cold region. The scope of work included field and laboratory evaluations of rapid-setting concrete repairs on both pavement panels and bridge decks in Utah. Six sites in northern Utah were selected by Utah Department of Transportation (UDOT) personnel for evaluation. At the time of inspection, the repairs had been in service for 4 to 5 years. Regarding field research, cracking and scaling were observed to be the most prevalent distresses among the sites evaluated in this research. Schmidt rebound numbers ranged from 40 to 55, which corresponds to a range of 5500 to 8700 psi, and all resistivity values correspond to a corrosion potential classification of “low.” Regarding laboratory research, stiffness values ranged from 3647 to 5431 ksi. All compressive strength values, which ranged from 5213 to 10867 psi, exceeded the minimum compressive strength of 5200 psi required by UDOT. Splitting tensile strength values ranged from 642 to 864 psi. Rapid chloride permeability test values corresponded to classifications of “negligible” or “very low,” and the absorption values of these specimens ranged from 7.5 to 9.9 percent. The hardened air void analyses indicated total air contents ranging from 4.6 to 11.9 percent, where the lowest and highest total air contents are outside the limits specified by UDOT, and microscope photographs suggest improper finishing practices and inadequate surface curing for those cores. The chloride concentrations, generally decreasing with increasing depth, ranged from less than 0.1 to 12.8 lb Cl- /yd3 of concrete within the upper 4 in. With recommended improvements in mixture design, finishing, and curing, rapid-setting concrete batched using volumetric concrete mixers should continue to be used for repairs of concrete pavement panels and bridge decks in Utah to expedite the concrete curing process and thereby minimize the impacts of lane closures on traffic.]]></description>
      <pubDate>Thu, 02 Jul 2026 11:04:35 GMT</pubDate>
      <guid>https://trid.trb.org/View/2719342</guid>
    </item>
    <item>
      <title>Performance evaluation of binders and bituminous concrete mixes modified with anti-stripping agents and polypropylene fibre</title>
      <link>https://trid.trb.org/View/2633395</link>
      <description><![CDATA[In this research, the CRMB-55 binder was utilised to improve the performance of asphalt concrete pavements while also addressing environmental concerns. Further, the effect of the addition of two modifiers, namely liquid anti-stripping agents (Fixtone-360, Wetbond-S and Wetbond-SP) and 6 mm length polypropylene fibre on bitumen binder and bituminous concrete mixes of grading II (BC, G-II), was evaluated. For this purpose, a dynamic shear rheometer (DSR) was used to identify the rheological behaviour of asphalt binders. For assessing the mechanical properties of asphalt concrete mixes, tests such as Marshall tests, indirect tensile strength and durability tests were performed. The findings conferred that the performance of the binder against rutting was improved with the addition of both modifiers. Further, both the modifiers, alone and in combination, significantly improved the mechanical performance of bitumen mixes. However, the blend of Wetbond-S anti-stripping agent (0.04%) and polypropylene fibre (0.6%) yielded the best rheological and mechanical performance.]]></description>
      <pubDate>Tue, 10 Mar 2026 09:56:53 GMT</pubDate>
      <guid>https://trid.trb.org/View/2633395</guid>
    </item>
    <item>
      <title>Factors Affecting Productivity of Central Plant Concrete Mixers: Tune Up the Cycle Time - Reduce the Delays</title>
      <link>https://trid.trb.org/View/2658073</link>
      <description><![CDATA[The data contained in this report are strictly of a fact-finding nature. The commentary is intended for informational and explanatory purposes and should not be considered critical under any circumstances, It is recognized that conditions on individual jobs frequently warrant operational practices which are not conducive to optimum equipment performance or productivity. The actual field studies were made on typical, active jobs by the Structures and Applied Mechanics Division, Office of Research and Development, Bureau of Public Roads, with the aid of junior engineer personnel in-training, in cooperation with the respective highway departments, contractors, and manufacturers. The data findings reflect plant operations on 20 different projects in widely scattered regions of the continental States. This summary of job performance data has been prepared in response to indications that the information can be of significant value to the highway industry.]]></description>
      <pubDate>Sun, 08 Mar 2026 16:14:50 GMT</pubDate>
      <guid>https://trid.trb.org/View/2658073</guid>
    </item>
    <item>
      <title>Study of the Circularity of Recycled Concrete Aggregates Subjected to Different Mechanical and Chemical Treatments</title>
      <link>https://trid.trb.org/View/2551113</link>
      <description><![CDATA[Concrete is one of the most popular construction materials, but it is still not considered sustainable. The introduction of recycled concrete aggregate (RCA) as a substitute for natural aggregate (NA) might make concrete align with the principles of circular economy. Unlike NA, RCA is not a homogeneous material as it is composed of old aggregates and adherent mortar. It is more porous than NA, so it results in lower strength and higher absorption. Several attempts have been made to improve the performance of RCA; however, not all studies prioritize an approach that can be feasible on a large scale. In addition, factors that enhance or decrease the performance of cast concrete mixes include the aggregate gradation, shape, and quantity of fines. The objective of this paper is to assess how the circularity, quantity of fines, roundness, and surface characterization of aggregates changes over time with respect to treatments such as mechanical and chemical treatments that can be extended on a large scale without a strong environmental impact. It was noted that acetic acid results in a superfluous additional element that does not greatly affect the results, since a considerable difference in the circularity, porosity, and fine number of aggregates can be produced by changing the timing and the size of the steel nuts used in the mechanical treatment.]]></description>
      <pubDate>Mon, 12 May 2025 17:08:56 GMT</pubDate>
      <guid>https://trid.trb.org/View/2551113</guid>
    </item>
    <item>
      <title>Control Strategy for a Non-Hybrid Hydrostatic Transmission Construction Vehicle Based on Power Follower</title>
      <link>https://trid.trb.org/View/2475201</link>
      <description><![CDATA[To achieve energy-saving control of non-hybrid Hydrostatic Transmission Construction Vehicles (HST-CVs) with traditional closed-loop Hydrostatic Transmission (HST) for both propulsion and working systems, this paper presents a control strategy for non-hybrid HST-CVs by referring to the power follower method of the hybrid Energy Management Strategy (EMS). Through the implementation of the presented control strategy by coordinated control of the engine speed and hydraulic pump displacement, the engine can be controlled to operate at the pre-set low Brake Specific Fuel Consumption (BSFC) area, similar to that of the hybrid vehicles adopting a power follower control strategy but without the additional installation of accumulators in the hydraulic system. The effect of the control strategy is verified via experimental tests and MATLAB/SIMULINK–AMESIM COLlaborative SIMulation (COSIM). The simulation results show that the proposed control strategy can achieve the expected control target under both highway and off-road conditions.]]></description>
      <pubDate>Fri, 13 Dec 2024 17:02:43 GMT</pubDate>
      <guid>https://trid.trb.org/View/2475201</guid>
    </item>
    <item>
      <title>Zero Emission Concrete Mixer Trucks: Comparison of Battery Electric and Hydrogen Fuel Cell Powertrains</title>
      <link>https://trid.trb.org/View/2458627</link>
      <description><![CDATA[This study aims to compare the feasibility of battery electric and hydrogen fuel cell powertrains for concrete mixer trucks to determine which is the better zero-emission powertrain for the industry to transition towards. Duty cycle modeling simulations are used to estimate both the component specifications required to meet the operational requirements of the vehicles, and the associated performance of the powertrain technologies. Associated costs for fleets are compared using Total Cost of Ownership (TCO) assessments. The duty cycle modeling results show that a battery electric mixer would consume up to 4 kWh of energy per mile on average when considering the auxiliary loads, which is around twice that of a typical class 8 battery electric truck. A truck with a battery size resulting in only an 80-mile range would have a 10% payload penalty, even with additional weight allowances for zero-emission trucks. A fuel cell electric mixer truck could have a 150-mile range but would still have a payload penalty, even with the additional weight allowances. A battery swap-capable truck could have no payload penalty compared to diesel, but would require swapping before each delivery, and adding battery swapping stations could be an issue at certain plants. The TCO of fuel cell trucks is currently 27% higher than that of diesel trucks. The TCO of battery electric trucks could be lower than that of diesel models as of today, and could be 25% lower than diesel TCO by 2030, while the fuel cell truck TCO would still be 10% higher than diesel, even by 2030. Based on this analysis, a battery swap concrete mixer truck could be the best zero-emission option for this application, but existing chassis are not currently available in the US. The lack of existing battery swap-capable chassis availability in the US will be a substantial barrier for battery swap mixer trucks, and custom solutions for a mixer application will likely not be cost-effective due to the limited yearly sales volume of concrete mixer trucks.]]></description>
      <pubDate>Thu, 05 Dec 2024 09:38:10 GMT</pubDate>
      <guid>https://trid.trb.org/View/2458627</guid>
    </item>
    <item>
      <title>Evaluation of Impact of Mixing Method on Laboratory- and Plant-Produced Fiber-Reinforced Asphalt Mixture</title>
      <link>https://trid.trb.org/View/2350724</link>
      <description><![CDATA[The addition of fibers to asphalt mixtures has the potential to improve the resistance of asphalt mixtures to cracking and permanent deformation (rutting). However, the state (distribution) of fibers in the asphalt mix is critical parameter in determining performance enhancement. This study evaluated the impact of different laboratory mixing methods (mainly Hobart and bucket) on fiber distribution and selected a method comparable to plant-produced fiber-reinforced mixes. The laboratory performance of plant-mixed lab-compacted (PMLC) and lab-mixed lab-compacted (LMLC) fiber-reinforced mixtures was compared. Four types of laboratory and plant mixtures [unreinforced, polyolefin and aramid (PFA) fibers at 0.05% dosage, and Sasobit-coated aramid (SCA) fibers at 0.01% and 0.02% dosages] were produced to compare the laboratory performance of asphalt mixtures. The cracking resistance [evaluated using indirect tensile strength (ITS) and semicircular bend (SCB) tests], rutting susceptibility [evaluated using flow number (FN) and the Hamburg wheel tracking test (HWTT)], durability (evaluated using Cantabro loss), and fatigue (evaluated using a uniaxial fatigue test) performance of control and fiber-reinforced asphalt mixtures were evaluated. Among laboratory mixing methods, a bucket mixer was selected to produce LMLC samples because it produced the maximum fiber distribution (87% of fibers in the individual state). Laboratory performance testing results showed that PFA-reinforced mixtures enhanced the rutting performance regardless of mixing method. The mixtures with PFA 0.05% and SCA 0.01% fibers were highly durable and had better dynamic modulus (|E*|) at low frequency and high temperature. Cracking performance was improved with the addition of SCA fibers into the mix; however, fiber-reinforced mixes (PFA 0.05% and SCA 0.01%) had higher fatigue damage tolerance, except SCA 0.02% reinforced mix. The laboratory bucket mixing method is representative of plant-produced fiber-reinforced mixtures, and laboratory performance results were consistent for laboratory bucket and plant produced mixtures.]]></description>
      <pubDate>Fri, 29 Mar 2024 16:58:29 GMT</pubDate>
      <guid>https://trid.trb.org/View/2350724</guid>
    </item>
    <item>
      <title>Feasibility Study of Low-Cement Concrete Mixes with E5 Internal Cure and Liquid Fly Ash</title>
      <link>https://trid.trb.org/View/2201940</link>
      <description><![CDATA[The University of Nebraska started a research project back in 2021 looking into Low-Cement Concrete Mixtures for Bridge Decks and Rails.  Due to the current NDOT concrete mixture for bridge decks and rails (known as 47BD) requires at least seven sacks of cementitious materials (IP/IT) per cubic yard and a minimum compressive strength of 4000 psi.  Based on the preliminary results from mixes prepared in the laboratory by the University, the Lower Cement Content (LCC) mixes show the following characteristics listed below.
(1) Slightly lower workability (i.e. slump and flow) than 47BD, which requires higher dosage of superplasticizer.
(2) Optimized 47BD-Cement Reduce 100lbs (O47BD-100) and O47BD-R150 have significantly longer set time (initial and final) compared to O47BD-R50 and 47BD. 	
(3) LCC Mixes shows mechanical properties (Compressive Strength, Modulus of Elasticity and Flexure and bond strength) comparable to the 47BD control.
(4) Durability properties (F/T, resistivity, and permeability) of LCC are comparable or even superior to those of 47BD.
(5) Shrinkage Results LCC mixes shows less shrinkage than the 47BD control.
The Materials and Research PCC Engineer is proposing to perform all the mixes listed in Table 2 from a ready mixed truck to confirm the mechanical and durability properties. As well as, introducing E5 Internal Cure and E5 Liquid Fly Ash for the of placement improving workability, longer window for finishing, minimal bleed rate, consistence air entrainment and enhancing cement/paste reduction. ]]></description>
      <pubDate>Fri, 23 Jun 2023 12:46:47 GMT</pubDate>
      <guid>https://trid.trb.org/View/2201940</guid>
    </item>
    <item>
      <title>Half-car model, finite element analysis and active control for vibrations of a truck concrete mixer</title>
      <link>https://trid.trb.org/View/1991542</link>
      <description><![CDATA[This research focuses on the dynamic effect of vibrations caused by concrete mixer on the driver or passenger. The complete model for the concrete mixer is studied using finite element modelling technique through CATIA software. The most stringent vibrational mode on the passenger is the first mode at 73 rad/s (11.7 Hz), the second mode was found at 389 rad/s (62 Hz) and the third one at around 1,237 rad/s (197 Hz). The same system is simulated using MATLAB software based on half-car model and the same results with the same mode has been found which proves that the studied model is correct and representative. The integral force feedback (IFF) control technique is implemented here to damp and control the oscillations of the passenger's seat. IFF proved very high authority and robustness besides to its simplicity of use and implementation.]]></description>
      <pubDate>Wed, 24 Aug 2022 15:05:36 GMT</pubDate>
      <guid>https://trid.trb.org/View/1991542</guid>
    </item>
    <item>
      <title>Mixing Phase Study of a Concrete Truck Mixer via CFD Multiphase Approach</title>
      <link>https://trid.trb.org/View/1903808</link>
      <description><![CDATA[This paper proposes a multiphase computational fluid dynamics (CFD) model to investigate the mixing process of an off-road self-loading concrete mixer drum. A multiphase Eulerian-Eulerian approach is used in a transient simulation for studying how sand and gravel move into the cement paste during the drum rotation. Inert materials were simulated as dispersed solid particles with various diameters and the cement paste as a continuum non-Newtonian-fluid. An experimental calibration of the separated materials was performed. For the solid–liquid interaction, a model found in the literature was used. The results describe motion of the mixture, accumulation areas of the aggregates, and calculated velocities of sand and gravel into the cement paste during the drum rotation. Furthermore, viscosity of the mixture as a function of the solid volume fractions has been analyzed. Validation was achieved by experimental numerical comparison of the drum torque curve at the start of mixing. This model can be used to design more efficient concrete mixers and to better understand some fluid dynamics aspects at the beginning of the concrete mixing process.]]></description>
      <pubDate>Thu, 20 Jan 2022 12:14:40 GMT</pubDate>
      <guid>https://trid.trb.org/View/1903808</guid>
    </item>
    <item>
      <title>Influences of Roller Diameter Error on the Mechanical Properties and Fatigue Life for the Main Bearing of Rotating Drum in Concrete Mixing Truck</title>
      <link>https://trid.trb.org/View/1738042</link>
      <description><![CDATA[A concrete mixing truck rotating drum's supporting main bearing (RDSMB) is usually a double row spherical roller bearing (SRB). In actual manufacturing, the roller diameter inevitably has a certain error, this error should have a great influence on the mechanical properties and fatigue life of the bearing. In this paper, the RDSMB of a certain type of concrete mixing truck is studied. The calculating equations are established to get the radial load and axial load acting on the main bearing. A mechanical model for SRB has been derived through the force analysis considering radial load, axial load, inner ring tilting angle and roller diameter error. The effects of single roller diameter error and random distribution errors of two rows of rollers on the axis orbit, roller maximum load, roller load experience and the fatigue life of RDSMB are studied. A series of influence relationship curves are obtained and analyzed.]]></description>
      <pubDate>Fri, 20 Nov 2020 11:06:21 GMT</pubDate>
      <guid>https://trid.trb.org/View/1738042</guid>
    </item>
    <item>
      <title>A Pre-Warning Method for Cornering Speed of Concrete Mixer Truck</title>
      <link>https://trid.trb.org/View/1702015</link>
      <description><![CDATA[The high gravity center of the concrete mixer truck reduces the truck’s stability while steering. The rolling stirring tank makes the stability even worse than the regular engineering vehicle due to the dynamic variation of the centroid position. Most of the researches on the rollover stability of concrete mixer trucks focus on the rollover model establishment and dynamic simulation module. The change of concrete centroid is ignored when the safety cornering speed is calculated. This paper proposes a pre-warning method for the cornering speed of concrete mixer trucks based on centroid dynamic simulation. In the method, the mixing tank stirring model and the vehicle driving dynamic model are established on the Fluent and TruckSim simulation platforms, respectively. The theoretical speed threshold obtained by simulation is used as the evaluation index of the warning speed in the curve. Firstly, the dynamic simulation of the stirring tank model is carried out by Fluent. According to Newton Leibniz numerical calculation method, Matlab is used to obtain the mathematical model of the centroid position and the main parameters of the stirring tank. Then the model is verified by the neural network algorithm. Finally, according to the dynamic position and lateral acceleration of the vehicle’s centroid, the dynamic simulation is carried out by TruckSim to obtain the theoretical speed threshold. The pre-warning system can warn the driver according to the comparison of real-time speed and calculated velocity threshold. In this paper, a 7.8 m3 concrete mixer truck is selected for simulation experiments. The results show that the lateral offset of the centroid is up to 206.4 mm and the maximum lateral force is 682N under normal working conditions, and the safe turning speed of the vehicle is reduced by at least 4.71% due to the centroid change. The pre-warning method proposed in this paper can improve the safety of cornering traffic effectively, and can be utilized in the further intelligent transportation system.       ]]></description>
      <pubDate>Tue, 26 May 2020 10:16:22 GMT</pubDate>
      <guid>https://trid.trb.org/View/1702015</guid>
    </item>
    <item>
      <title>Automated Measurement of Concrete Slump Using the Verifi Sytem</title>
      <link>https://trid.trb.org/View/1693783</link>
      <description><![CDATA[In this research, twenty batches of concrete with six different mixture proportions were tested with VERIFI to evaluate 1) accuracy and repeatability of VERIFI measurements, 2) ability of VERIFI to adjust slump automatically with water and admixture, and 3) effects on concrete properties when water and admixture are added continuously during transit instead of adding whole at the plant or jobsite. For each batch, concrete was sampled every 30 minutes up to 90 minutes and tested for slump, temperature, air content, unit weight, water content, bleeding (select batches), and rheology (select batches). Cylindrical concrete specimens were cast at 90 minutes and were tested for compressive strength at 3 and 28 d (or 3 and 14 d for Illinois Department of Transportation mixes). The statistical analysis of results shows that the accuracy of VERIFI system in measuring slump and temperature of concrete in a truck mixer is 0.5-in. and 1.5 °F, respectively. This is within the acceptable variation limit stated in ASTM C143 and ASTM C1064. The confidence interval analysis of slump measurements reveals that the probability of having average slump deviation larger than 0.56 in. is less than 5%. The accuracy of VERIFI was not affected by load size or if concrete is mixed in different truck mixers.]]></description>
      <pubDate>Thu, 16 Apr 2020 12:22:52 GMT</pubDate>
      <guid>https://trid.trb.org/View/1693783</guid>
    </item>
    <item>
      <title>Concrete mixing truck as a rheometer</title>
      <link>https://trid.trb.org/View/1666797</link>
      <description><![CDATA[An increasing interest has emerged in correlating the output of the concrete mixing truck to values obtained by rotational rheometers. The output of the former has usually been the hydraulic pressure needed to turn the drum. In such research, experimental errors can be higher than usual, which makes it harder to obtain confident relationships. To better understand the physical characteristics of the truck's rheological values, the above analysis is made by a series of computer simulations (i.e. with computational fluid dynamics - CFD). From this, it is evident that the slope H of the truck's pressure values depends both on the plastic viscosity μ as well as on the yield stress τ0. However, for the intercept G of the truck's values, it is mostly dependent on the yield stress τ0. In addition to this, both values H and G depend on volume of concrete in the truck as well as on density.]]></description>
      <pubDate>Mon, 25 Nov 2019 11:27:12 GMT</pubDate>
      <guid>https://trid.trb.org/View/1666797</guid>
    </item>
    <item>
      <title>Effective ready mixed concrete supply adjustments with inoperative mixers under stochastic travel times</title>
      <link>https://trid.trb.org/View/1507895</link>
      <description><![CDATA[The purpose of this study is to develop a systematic scheduling model that will help ready mixed concrete (RMC) carriers/suppliers with effective scheduling adjustment after temporary breakdown of mixers under stochastic travel times. The model is formulated as a mixed integer network flow problem with side constraints that is characterized as non-deterministic polynomial-time (NP)-hard. The authors employ problem decomposition and relaxation techniques, with a mathematical programing solver, to develop an algorithm that is capable of efficiently solving the problem. A simulation-based evaluation method is also proposed to evaluate the model, joined with a deterministic model, as well as the method currently used in actual operations. Finally, a case study is performed using real operating data from a Taiwan RMC firm. The preliminary results demonstrate that the stochastic model and the solution algorithm could be useful to reduce system cost for the RMC carrier in actual operations.]]></description>
      <pubDate>Wed, 25 Apr 2018 09:22:26 GMT</pubDate>
      <guid>https://trid.trb.org/View/1507895</guid>
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