The use of small diameter whole-culm (bars) and/or split bamboo (a.k.a. splints or round strips) has often been proposed as an alternative to relatively expensive reinforcing steel in reinforced concrete. The motivation for such replacement is typically cost-bamboo is readily available in many tropical and sub-tropical locations, whereas steel reinforcement is relatively more expensive-and more recently, the drive to find more sustainable alternatives in the construction industry. This review addresses such 'bamboo-reinforced concrete' and assesses its structural and environmental performance as an alternative to steel reinforced concrete. A prototype three bay portal frame, that would not be uncommon in regions of the world where bambooreinforced concrete may be considered, is used to illustrate bamboo reinforced concrete design and as a basis for a life cycle assessment of the same. The authors conclude that, although bamboo is a material with extraordinary mechanical properties, its use in bamboo-reinforced concrete is an ill-considered concept, having significant durability, strength and stiffness issues, and does not meet the environmentally friendly credentials often attributed to it.
We measure and model the effect of
CO2 addition on equilibrium
composition and volume expansion for solvent system 2-methyltetrahydrofuran
(2-MTHF)/water. Our experimental data cover pressures from p = (0.03 to 3.51) MPa and temperatures from T = (293 to 363) K. Following the protocol we reported in Glass et
al. (Fluid Phase Equilibria
2017, 433, 212–225), we apply infrared and Raman spectroscopy
to monitor the organic and aqueous phases inline, respectively. CO2 solubility in binary system 2-MTHF/water is similar to that
in tetrahydrofuran (THF)/water, but the effect of CO2 addition
on the miscibility gap is lower on an absolute scale. We employ the
perturbed-chain statistical associating fluid theory (PC-SAFT) equation
of state (EOS) with physically inspired association schemes for the
thermodynamic modeling of the chemical system. We additionally provide
parameters for PC-SAFT with association schemes that are readily usable
in the Aspen Suite. Ternary system CO2/2-MTHF/water is
best described by a model with a total of six binary parameters yielding
root-mean-square deviations (RMSDs) of 0.015 mol mol–1 for the organic phase and 0.002 mol mol–1 for
the aqueous phase. We use the EOS to predict the volume expansion
in binary system CO2/2-MTHF. Calculated results are in
good agreement with experimental data (RMSD = 5.1%). We further investigate
the influence of water on volume expansion in ternary system CO2/2-MTHF/water in a theoretical study. The methods and data
presented in this work enable the targeted utilization of green solvent
system CO2/2-MTHF/water on laboratory and processing scales.
We investigate the influence of sulfate salts and sulfuric acid on the equilibrium behavior of 2-methyltetrahydrofuran (2-MTHF)/H 2 O/5hydroxymethylfurfural (5-HMF). Liquid−liquid equilibrium measurements are performed at atmospheric pressure and in a temperature range of T = (293−333) K. The compositions of the aqueous and organic phases, together with the dissociation state of the sulfate species, are determined with infrared spectroscopy and Indirect Hard Modeling. We show that the addition of the salts Na 2 SO 4 and Li 2 SO 4 results in salting out of 2-MTHF and 5-HMF from the aqueous phase. With increasing temperature, this effect gets less pronounced. In contrast, the addition of H 2 SO 4 does not result in any salting-out behavior. The investigation of the dissociation states shows that H 2 SO 4 dissociates to HSO 4 − while Na 2 SO 4 and Li 2 SO 4 dissociate completely to SO 4 2−. Parameter regression is performed to model the liquid−liquid equilibrium with the electrolyte perturbed-chain statistical associating fluid theory (ePC-SAFT) equation of state. For the analyzed salts, Na 2 SO 4 and Li 2 SO 4 , the performed parameter regression accurately predicts the measurement results. Still, we observe slight deviations between measured values and modeling when predicting the liquid−liquid equilibrium and the liquid density in the presence of sulfuric acid.
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