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This recommendation is an outcome of the work carried out by a working group within the RILEM Technical Committee 238-SCM “Supplementary Cementitious Materials”. The working group studied the effect of supplementary cementitious materials on the pore solution, the microstructure and the hydration product assemblage of hardened Portland cements blended with common supplementary cementitious materials. The recommendation reflects the results of a round robin test programme on common hydration stoppage methods in 10 participating laboratories. Among four different methods tested, solvent exchange by isopropyl alcohol (isopropanol) gave the best results in terms of preservation of the cement hydrate assemblage and overall reproducibility of the results [1]. The current protocol is developed based on best laboratory practices of the participating laboratories and literature reports [2–4]. The presented hydration stoppage protocol is recommended for the study of Portland cement-based hydrate assemblages by common material characterization techniques such as thermogravimetry and X-ray powder diffraction.

The sorption of superabsorbent polymers (SAP) and kinetics of the process can differ significantly depending on SAP composition and grading as well as on properties of sorbed fluid. Several performance-oriented testing methods of SAP have been proposed in the literature to determine the individual sorption of polymers and to link them with their effects when embedded in cementitious materials as a multifunctional admixture. This recommendation focuses on the two main sorption capacity testing methods of free sorption assessment, the tea-bag and filtration methods. It includes experimental prescriptions to obtain consistent results and to draw conclusions as to whether or not a particular SAP is suitable for a cementitious material.

A primary aim of RILEM TC 267-TRM: “Tests for Reactivity of Supplementary Cementitious Materials (SCMs)” is to compare and evaluate the performance of conventional and novel SCM reactivity test methods across a wide range of SCMs. To this purpose, a round robin campaign was organized to investigate 10 different tests for reactivity and 11 SCMs covering the main classes of materials in use, such as granulated blast furnace slag, fly ash, natural pozzolan and calcined clays. The methods were evaluated based on the correlation to the 28 days relative compressive strength of standard mortar bars containing 30% of SCM as cement replacement and the interlaboratory reproducibility of the test results. It was found that only a few test methods showed acceptable correlation to the 28 days relative strength over the whole range of SCMs. The methods that showed the best reproducibility and gave good correlations used the R3 model system of the SCM and Ca(OH)2, supplemented with alkali sulfate/carbonate. The use of this simplified model system isolates the reaction of the SCM and the reactivity can be easily quantified from the heat release or bound water content. Later age (90 days) strength results also correlated well with the results of the IS 1727 (Indian standard) reactivity test, an accelerated strength test using an SCM/Ca(OH)2-based model system. The current standardized tests did not show acceptable correlations across all SCMs, although they performed better when latently hydraulic materials (blast furnace slag) were excluded. However, the Frattini test, Chapelle and modified Chapelle test showed poor interlaboratory reproducibility, demonstrating experimental difficulties. The TC 267-TRM will pursue the development of test protocols based on the R3 model systems. Acceleration and improvement of the reproducibility of the IS 1727 test will be attempted as well.

The original publication is available at the publisher’s web site: http://link.springer.com/article/10.1617/s11527-014-0485-2/fulltext.html#copyrightInformation. This article is accepted for publication, it is copyrighted by RILEM, and readers must contact RILEM for permission to reprint or use the material in any form.

Textile Reinforced Mortar (TRM), also known as Fabric Reinforced Mortar or Fabric Reinforced Cementitious Matrix, composites are an emerging technology for the external repair and strengthening of existing structures. For most applications, the effectiveness of the TRM reinforcement relies on its bond performance. This recommendation identifies the best practice to characterize the bond behaviour of TRM. A shear bond test method is proposed to determine the peak axial stress (associated with the maximum load that can be transferred from the structural member to the externally bonded TRM reinforcement), the stress–slip relationship and the failure mode that controls the TRM-to-substrate load transfer capacity. Guidelines on specimen manufacturing, experimental setup, test execution, and determination of test results are provided.

This recommendation is the outcome of research conducted by a working group within the RILEM Technical Committee 236-BBM ‘Bio-aggregate-based building Materials’. The work of the group related to the study of construction materials made from plant particles. The major raw material utilised being renewable, recyclable and easily available plant particles. These particles are obtained from the processing of hemp, flax, miscanthus, pine, maize, sunflower, bamboo and other plants. In this report, the outcome of the Round Robin Testing is centred on hemp because hemp shiv is the bio-aggregate that is the most widely used in building materials and the most studied in the literature. The first round robin test of the TC-BBM published in the State of The Art Report of Technical Committee 236-BBM ‘Bio-aggregate-based building Materials’ was carried out to compare the protocols in use by the different laboratories (labs) to measure initial water content, bulk density, water absorption, particle grading and thermal conductivity. The aim was to define a standardised characterisation protocol developed from those used by the different labs. The different methodologies used by 7 labs constitute a set of statistically representative data which have been analysed to develop this recommendation for the characterisation of hemp shiv.

This recommendation is devoted to the use of superabsorbent polymers (SAP) in mitigating autogenous shrinkage of concrete and has been prepared by the working group acting within RILEM TC 260-RSC. The recommended procedure for designing mix compositions of concrete with SAP is given. Dry SAP particles of small size should be added to concrete along with additional mixing water that SAP absorb upon mixing. The SAP particles release water during hardening of concrete to compensate for chemical shrinkage and consequently reduce autogenous shrinkage. The procedure for designing mix composition is based on finding a trade-off between mitigation of autogenous shrinkage and possible negative effects on concrete properties (e.g., mechanical properties, workability). A theoretical guideline is provided based on compensating the volume of chemical shrinkage with (additional) internal curing water to be absorbed by the SAP and based on the measured absorption capacity of the SAP.

The paper presents the experience of a working group within the RILEM Technical Committee 223-MSC ‘Masonry Strengthening with Composite materials’, aimed at developing a standardized, reliable procedure for characterizing the bonding mechanism of masonry elements strengthened with composite materials under shear actions. Twelve laboratories from European universities and research centers were involved. Two different set-ups were compared, for single-lap and double-lap shear tests (the latter in two versions). Four kinds of fiber fabrics, i.e., glass, carbon, basalt and steel, were applied with epoxy resins (wet lay-up system) to clay brick units, for a total of 280 monotonic tests. The results provided information regarding the response of externally bonded-to-brick composites in terms of observed failure mechanisms, load capacity, effective transfer length, and bond shear stress–slip behavior. The test results of the 12 laboratories constitute a set of statistically representative data which may conveniently be used for setting appropriate design provisions and guidelines.