Concrete Formula Research Articles

An industrial demonstration study on CO2 mineralization curing for concrete

SummaryA 10,000 ton-CO2/y mineralization curing (CMC) process was demonstrated in Jiaozuo city, China by retrofitting a traditional autoclaved curing plant. An industrial concrete formula with synergistic effects of aggregate gradation, early hydration, and alkali excitation was developed using local solid wastes resources. Approximately 90% of the raw materials, including fly ash, furnace blaster slag, steel slag, and carbide slag, came from coal-based industries. An extraordinary phenomenon of high-temperature accumulation from room temperature to 140°C was first observed in an industrial scale because of the rapid and strong exothermic carbonation reaction. A step pressure-equalizing procedure was developed to achieve a rapid carbonation rate, a high CO2 conversion ratio of >98%, and efficient carbonation exotherm recycling. The global warming potential life cycle analysis revealed that compared with autoclaved curing, CMC showed significantly decreased the emission of 182 kg CO2-Eq/m3-product, with direct CO2 sequestration accounting for ∼65% of the reduction.

Experimental Analysis of Recycled Aggregate Concrete Beams and Correction Formulas for the Crack Resistance Calculation

This paper studies the similarities and the differences between natural aggregate concrete (NAC) beams and recycled aggregate concrete (RAC) beams in terms of concrete material properties, bearing capacity, and crack resistance and further proposes correction formulas for cracking moment calculation of RAC beams that consider different recycled aggregate substitution ratios. First, the basic mechanical properties (e.g., cube compressive strength, axial compressive strength, and elastic modulus) of RAC blocks were tested; second, comparative bending tests of RAC beams and natural aggregate concrete beams were conducted, in order to obtain the cracking moments, yield bending moments, ultimate bending moments, mid-span deflections and crack development forms; finally, numerical simulations were performed to investigate the cracking performances of RAC beams. Through analyzing the experimental results, it is found that the crack development pattern of RAC beams resembles that of natural aggregate concrete beams, while the cracking performance of RAC beams significantly deviates from that of NAC beams. Finally, the correction formulas for the cracking moment calculation of RAC beams are proposed based on the numerical simulation results and verified by data from other researchers, which can be regarded as a correction for the cracking moment calculation formulas in the current code for RAC beams with respect to varied recycled concrete aggregate substitution ratios.

The Cauchy problems for q-difference equations with the Caputo fractional derivatives

The fractional differential equations play important roles due to their numerous applications and also for the important role they play not only in mathematics but also in other sciences. In the present research work, we build up the explicit solutions to linear fractional q-differential equations with the q-Caputo fractional derivative of real order a > 0. To speak more precisely, we will achieve our main results we use that this Cauchy type q-fractional problem is equivalent to a corresponding Volterra q-integral equation. After that, by using the method of successive approximations is applied to solve the Volterra q-integral equation we construct the the explicit solutions to linear fractional q-differential equations. In the same way we have the more general homogeneous fractional q-differential equation with the Caputo fractional q-derivative of real order a > 0 and we give other The (Mittag-Leffler) q-function. Finally, some examples are presented to illustrate our main results in cases where we can even give concrete formulas for these explicit solutions.

The closures of test configurations and algebraic singularity types

Given a Kähler manifold X with an ample line bundle L, we consider the metric space of finite energy geodesic rays associated to the Chern class c1(L). We characterize rays that can be approximated by ample test configurations. At the same time, we also characterize the closure of algebraic singularity types among all singularity types of quasi-plurisubharmonic functions, pointing out the very close relationship between these two seemingly unrelated problems.By Bonavero's holomorphic Morse inequalities, the arithmetic and non-pluripolar volumes of algebraic singularity types coincide. We show that in general the arithmetic volume dominates the non-pluripolar one, and equality holds exactly on the closure of algebraic singularity types. Analogously, we give an estimate for the Monge–Ampère energy of a general finite energy ray in terms of the arithmetic volumes along its Legendre transform. Equality holds exactly for rays approximable by test configurations.Various other cohomological and potential theoretic characterizations are given in both settings. As applications, we give a concrete formula for the non-Archimedean Monge–Ampère energy in terms of asymptotic expansion, and show the continuity of the projection map from L1 rays to non-Archimedean rays.

On the abstract chromatic number and its computability for finitely axiomatizable theories

The celebrated Erdős–Stone–Simonovits theorem characterizes the asymptotic maximum edge density in F-free graphs as 1−1/(χ(F)−1)+o(1), where χ(F) is the minimum chromatic number of a graph in F. In [6, Examples 25 and 31], it was shown that this result can be extended to the general setting of graphs with extra structure: the asymptotic maximum edge density of a graph with extra structure without some induced subgraphs is 1−1/(χ(I)−1)+o(1) for an appropriately defined abstract chromatic numberχ(I). As the name suggests, the original formula for the abstract chromatic number is so abstract that its (algorithmic) computability was left open.In this paper, we both extend this result to characterize maximum asymptotic density of t-cliques in graphs with extra structure without some induced subgraphs in terms of χ(I) and we present a more concrete formula for χ(I) that allows us to show its computability when both the extra structure and the forbidden subgraphs can be described by a finitely axiomatizable universal first-order theory. Our alternative formula for χ(I) makes use of a partite version of Ramsey's Theorem for structures on first-order relational languages.

Creep Behaviour of Reinforced Concrete Beam under Long-Term Bending

Concrete structure after casting will be subjected to external load, peripheral components and other constraints, the overall performance of the structure under a long-term loading state will change continuously. In practical engineering, reinforcement is usually calculated and configured based on external load, but the role of reinforcement in the continuous loading process of concrete structure is not fully considered. Based on the elastic creep theory, this paper deduces the concrete creep calculation formula considering the influence of reinforcement, and analyses the law of the influence of reinforcement ratio and loading age on the strain and stress of concrete. The results show that the reinforcement can effectively restrain the deformation of concrete and reduce the load level of concrete.

Solution of the reconstruction-of-the-measure problem for canonical invariant subspaces

We study the Reconstruction-of-the-Measure Problem (ROMP) for commuting 2-variable weighted shifts \(W_{(\alpha ,\beta )}\), when the initial data are given as the Berger measure of the restriction of \(W_{(\alpha ,\beta )}\) to a canonical invariant subspace, together with the marginal measures for the 0–th row and 0–th column in the weight diagram for \(W_{(\alpha ,\beta )}\). We prove that the natural necessary conditions are indeed sufficient. When the initial data correspond to a soluble problem, we give a concrete formula for the Berger measure of \(W_{(\alpha ,\beta )}\). Our strategy is to build on previous results for back-step extensions and one-step extensions. A key new theorem allows us to solve ROMP for two-step extensions. This, in turn, leads to a solution of ROMP for arbitrary canonical invariant subspaces of \(\ell ^2({\mathbb {Z}}_+^2)\).

Aperiodic order and spherical diffraction, II: translation bounded measures on homogeneous spaces

We study the auto-correlation measures of invariant random point processes in the hyperbolic plane which arise from various classes of aperiodic Delone sets. More generally, we study auto-correlation measures for large classes of Delone sets in (and even translation bounded measures on) arbitrary locally compact homogeneous metric spaces. We then specialize to the case of weighted model sets, in which we are able to derive more concrete formulas for the auto-correlation. In the case of Riemannian symmetric spaces we also explain how the auto-correlation of a weighted model set in a Riemannian symmetric space can be identified with a (typically non-tempered) positive-definite distribution on mathbb {R}^n. This paves the way for a diffraction theory for such model sets, which will be discussed in the sequel to the present article.

Development of biomaterial fillers using eggshells, water hyacinth fibers, and banana fibers for green concrete construction

Water hyacinth fiber, banana fiber, and eggshell powder were used as biomaterial fillers for concrete reinforcement, obtained from agricultural and post-consumer wastes. Adding the 0.02 and 0.05 ratios (by weight) of bio-fillers into concrete enhanced the physical (water absorption, bulk density, and true density) and mechanical properties (compressive strength, tensile strength, flexural strength, and maximum load) of seven experimentally obtained concrete formulas. These results demonstrated that the optimum formulas of a concrete composite were obtained upon adding the 0.05 ratio (by weight) of eggshell powder followed by curing for 28 d. The best bio-filler for concrete composite is adding eggshell powder. The bulk density, true density, water absorption, compressive strength, tensile strength, flexural strength, and maximum load of concrete Formula 6 (obtained by mixing 0.05 ratio (by weight) of eggshell powder) are 2.245 ± 0.040 g/cm3, 2.252 ± 0.033 g/cm3, 1.62% ± 0.16%, 22.08 ± 0.66 MPa, 157.33 ± 35.63 MPa, 4.13 ± 0.21 MPa, and 55.68 ± 1.64 kN, respectively. Furthermore, the microstructure and phase formations of the concrete composites were analyzed by SEM and XRD.

The Effect of the Composition of a Concrete Mixture on Its Volume Changes.

The presented research aims to clarify the specific effect of the individual components of concrete with Portland cement CEM I 42.5 R on the volume changes of concrete. The effect of the filler component was evaluated from the point of view of the composition and type of aggregate (crushed versus mined) and from the point of view of the mineralogical composition of the aggregate. Concrete formulas with a maximum aggregate grain size of 16 and 22 mm were assessed. The effect of the binder component on the shrinkage of the concrete was monitored on the concrete mixtures produced using the same aggregate and maintaining the same strength class of concrete, C 45/55. The effect of the addition of finely ground limestone, finely ground granulated blast furnace slag and coal high-temperature fly ash was monitored. It was found that the maximum aggregate grain and the type of grading curve do not have a significant effect on the volume changes of concrete. Concretes with mined aggregates showed lower shrinkage than concretes with crushed aggregates. The most significant is the effect of the type of aggregate on the volume changes in the first 24 h. Mineral additives have a positive effect on the elimination of the volume changes of concrete, while the addition of high-temperature fly ash proved to be the most suitable.

Designing the Concrete Mix Design in order to Determine the Deviation Value of the Two Concrete Compressive Test Instruments (Pressure Test and Hammer Test)

The role of concrete material in building structures is a very important, in the other word almost all of structural building use concrete components. Using this research, we try to ascertain how big the deviation results from the two tools. Through laboratory research that is examined from the physical coarse aggregate material, fine aggregate, we get the job mix concrete formula. the quality of the concrete that we design is concrete K-200 kg / cm2. from the results of our job mix, the proportion of the concrete mixture for 1 m3 of concrete is as follows cement 351.85 kg, sand 780.42 kg, crushed stone 1077.73 kg, water 142.34 kg, then made as many as 15 pieces of cube specimens. Then for the finished structural test object, a building is made from the structure of the foundation, loop beams, columns, floor beams and floor slabs. When casting is carried out, the making of concrete cube specimens is taken back, respectively, the number of foundation test objects is 3 concrete cubes, 3 sloop blocks of concrete cubes, 3 columns, 3 beams and 3 floor plates. The average test results of these test tools are as follows: the pressure test using the concrete pressure test device is 211 kg / cm2, and the test result using the concrete hammer test is 195 kg / cm2.

Explicit solutions of the kinetic and potential matching conditions of the energy shaping method

<p style='text-indent:20px;'>In the context of underactuated Hamiltonian systems defined by simple Hamiltonian functions, the matching conditions of the energy shaping method split into two decoupled subsets of equations: the <i>kinetic</i> and <i>potential</i> equations. The unknown of the kinetic equation is a metric on the configuration space of the system, while the unknown of the potential equation are the same metric and a positive-definite function around some critical point of the Hamiltonian function. In this paper, assuming that a solution of the kinetic equation is given, we find conditions (in the <inline-formula><tex-math id="M1">\begin{document}$ C^{\infty} $\end{document}</tex-math></inline-formula> category) for the existence of positive-definite solutions of the potential equation and, moreover, we present a procedure to construct, up to quadratures, some of these solutions. In order to illustrate such a procedure, we consider the subclass of systems with one degree of underactuation, where we find in addition a concrete formula for the general solution of the kinetic equation. As a byproduct, new global and local expressions of the matching conditions are presented in the paper.</p>

New explicit algorithm based on the asymmetric hopscotch structure to solve the heat conduction equation

In this paper we will consider a new four-stage structure inspired by the well-known odd-even hopscotch method to construct new schemes for the numerical solution of the two-dimensional heat or diffusion equation. In this structure the first and the last time step are halved stage and therefore the time steps are shifted compared to each other for odd and even cells. We insert 10 concrete formulas into this structure to obtain 104 different combinations. First we test all of these in case of small systems with random parameters, and then examine the competitiveness of the best algorithms by testing them in case of large systems against popular solvers. We select the top 5 combinations, and demonstrate that these new methods are indeed effective if the goal is to produce results with acceptable accuracy in very short time.

Evaluation of Concrete Breakout Capacity of Single Anchors at Bridge Bearing Connection under Shear Loading

In this study, the breakout capacity of a single anchor specimen in concrete simulating the bridge bearing connection with the characteristics of reinforcement, anchor socket, bed concrete, and mortar was evaluated for shear. The concrete breakout capacities were compared based on the embedment length of the anchor socket and edge distance, and the difference between the existing design strength and the actual strength was determined, which indicated safety issues. In addition, the shear resistance performance of the effective anchor reinforcement was evaluated through the strain analysis of the reinforcement. Finally, Through the results of this study, a concrete breakout capacity formula that reflects the characteristics of the bridge bearing connection has been proposed.

The characteristic masses of Niemeier lattices

Let L be an integral lattice in the Euclidean space R n and W an irreducible representation of the orthogonal group of R n. We give an implemented algorithm computing the dimension of the subspace of invariants in W under the isometry group O(L) of L. A key step is the determination of the number of elements in O(L) having any given characteristic polynomial, a datum that we call the characteristic masses of L. As an application, we determine the characteristic masses of all the Niemeier lattices, and more generally of any even lattice of determinant ≤ 2 in dimension n ≤ 25. For Niemeier lattices, as a verification, we provide an alternative (human) computation of the characteristic masses. The main ingredient is the determination, for each Niemeier lattice L with non-empty root system R, of the G(R)-conjugacy classes of the elements of the umbral subgroup O(L)/W(R) of G(R), where G(R) is the automor-phism group of the Dynkin diagram of R, and W(R) its Weyl group. These results have consequences for the study of the spaces of au-tomorphic forms of the definite orthogonal groups in n variables over Q. As an example, we provide concrete dimension formulas in the level 1 case, as a function of the weight W , up to dimension n = 25.

Effect of Binder Components on the pH of Concrete Mixture with Low pH Intended for Deep Geological Repository for Radioactive Waste in the Czech Republic

This paper deals with the development and research of low pH concrete mixtures intended for the deep geological repository for radioactive waste. Mixtures, in particular those made from materials originating in the Middle Europe, specifically Czech Republic, were designed due to the diversity of the raw materials’ properties. In this first part, a large number of cement mortars were designed, on which the effect of active ingredients (microsilica, slag) on the pH value over time were tested. From the results of the cement mortars’ pH measured after 90 days, a concrete formula was designed. A mixture with a lower proportion of cement and a higher proportion of microsilica seems to be the best. The slag serves only as a supplement in the place value of several weight percent of the total binder volume. Also, the control measurements of basic material characteristics, such as volumetric mass density and compressive strength were performed on these mixtures.

A general q-expansion formula based on matrix inversions and its applications

In this paper, by the technique of matrix inversions, we establish a general q-expansion formula of arbitrary formal power series F(z) with respect to the base $$\begin{aligned} \left\{ z^n\frac{(az)_{n}}{(bz)_{n}}\bigg |n=0,1,2,\ldots \right\} . \end{aligned}$$ Some concrete expansion formulas and their applications to q-series identities are presented, including Carlitz’s q-expansion formula and a new partial theta function identity as well as a coefficient identity for Ramanujan’s $${}_1\psi _1$$ summation formula as special cases.

Liquidity in Equity Markets – Definitions and Formulae

The purpose of this paper is to set up a clear definition of liquidity in equity markets and to develop a liquidity factor to measure liquidity, including its formula. We claim that four necessary elements in sum are sufficient to define the term liquidity. Its structure is determined by the relations between these elements. To specify our considerations, we will focus on the trading of equity products in their home market when defining liquidity and deriving its formula. However, our deliberations can be transferred equally to any other liquidity pool and to the other modules of the value chain. To underline our assumptions, we will start with some general remarks about definitions which we then apply to the term liquidity. In a next step we will develop a concept of liquidity: A general and abstract definition for the liquidity of equity markets. This is the basic starting point for the concretization and individualization of the term liquidity. It enables us to measure liquidity in concrete situations in the real world. Having reached the highest level of concretization and individualization we are now able to apply the liquidity factor λ as the measured ease to trade a certain stock. We end up with some working definitions which are core for the development and application of the formula. After these rather theoretical considerations we turn to the concrete calculation of the liquidity factor λ. We spend some thoughts on general aspects for the calculation of liquidity before we derive a concrete formula for its measurement. We analyze this liquidity factor from different angles and also take a look at related formulae before we conclude our paper with an outlook on further objects of investigation. As to the methodology of this paper we will pursue a deductive approach. We will start with some general rules on liquidity before we successively narrow the range under consideration until we draw our conclusions on liquidity for a certain stock under predefined premises. Nevertheless, the results we will obtain are equally applicable to other securities with other predefined premises: They are applicable to equity markets in general.

A study on parameter estimation and suppression for smeared spectrum jamming based on short-time Fourier transform

We address the suppressing problem of smeared spectrum (SMSP) jamming from the mixed signal received by the radar. To this end, we resort to the time-frequency analysis algorithm and give the concrete expression formula of the short-time Fourier transform (STFT) of SMSP jamming. The proposed method is to estimate the parameters of the jamming signal based on the STFT result, and then the jamming signal is reconstructed and suppressed form the mixed signal. In order to perform effective interference even after the pulse compression process, the jamming-to-target ratio (JSR) is always positive. Based on this assumption, the estimation steps for different parameters of SMSP jamming are given, including the number of sub-waveforms, the amplitude, and the time delay. The influence of choosing different window is also considered in this paper. The estimated performance of this method is verified by Monte Carlo simulation, and the results show the effectiveness of the proposed method.

Volume of Hypercubes Clipped by Hyperplanes and Combinatorial Identities

There is an elegant expression for the volume of hypercube $[0,1]^n$ clipped by a single hyperplane. In the article, the formula is generalized to the case of more than one hyperplane. An important foundation for the result is Lawrence's formula and a way to weaken two restrictions of simplicity and non-parallelness in his formula is also considered. Several concrete volume formulas of clipped hypercubes are derived explicitly and the corresponding combinatorial identities are obtained as an application.