Inovadora brita graduada tratada com cimento de alto desempenho como concreto compactado com rolo

Cargnin, Andréia Posser; Balbo, José Tadeu; Bernucci, Liédi Legi Barianni

Andréia Posser Cargnin

laboratory work

samples preparation

testing

analysis

writing

Universidade de São Paulo, Escola Politécnica, Departamento de Engenharia de Transportes, São Paulo, SP, Brasil

https://orcid.org/0000-0003-1568-2756

José Tadeu Balbo

advising

supervision

analysis

review

Universidade de São Paulo, Escola Politécnica, Departamento de Engenharia de Transportes, São Paulo, SP, Brasil

https://orcid.org/0000-0001-9235-1331

Liédi Legi Barianni Bernucci

co-advising

supervision

analysis

review

Universidade de São Paulo, Escola Politécnica, Departamento de Engenharia de Transportes, São Paulo, SP, Brasil

Instituto de Pesquisas Tecnológicas do Estado de São Paulo, São Paulo, SP, Brasil

https://orcid.org/0000-0002-4768-0993

Corresponding author: Andréia Posser Cargnin. E-mail: andreia.cargnin@usp.br

Conflict of interest: Nothing to declare.

Editors: Diogo Ribeiro, Guilherme Aris Parsekian.

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Figure 1
Loosening and wall effects between particles in a polydisperse mixture. Source: Adapted from Larrard [²⁷27 F. Larrard, “Concrete mixture proportioning: a scientific approach,” in Modern Concrete Technology Series, A. Bentur and S. Mindess, Eds., London, UK: E. & F.N. Spon, 1999, pp. 1–403.].

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Figure 2
Flowchart of the experimental study

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Figure 3
Particle size distributions considered

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Figure 4
Distribution modulus calculated for DER-SP CTCS limits

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Figure 5
Distribution modulus calculated for EN 14227-1 CBGM2 limits

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Figure 6
Distribution modulus calculated for ACI-RCC limits

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Figure 7
Studied grading curve matching DER-SP

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Figure 8
Studied grading curve matching CBGM 2 (EN 14227-1)

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Figure 9
Studied grading curve matching ACI-RCC

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Figure 10
Studied grading curves together

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Figure 11
Virtual and real packing densities calculated for the selected mixtures

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Figure 12
Compaction curves for CBGM2 (EN 14227-1) mean grading curve

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Figure 13
Data acquisition during the modulus of elasticity test: (a) specimen under splitting tensile; (b) specimen after rupture; (c) specimen under uniaxial compression

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Figure 3
Particle size distributions considered

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Figure 4
Distribution modulus calculated for DER-SP CTCS limits

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Figure 5
Distribution modulus calculated for EN 14227-1 CBGM2 limits

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Figure 6
Distribution modulus calculated for ACI-RCC limits

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Figure 7
Studied grading curve matching DER-SP

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Figure 8
Studied grading curve matching CBGM 2 (EN 14227-1)

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Figure 9
Studied grading curve matching ACI-RCC

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Figure 10
Studied grading curves together

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Figure 11
Virtual and real packing densities calculated for the selected mixtures

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Figure 11
Virtual and real packing densities calculated for the selected mixtures

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Figure 12
Compaction curves for CBGM2 (EN 14227-1) mean grading curve

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Figure 13
Data acquisition during the modulus of elasticity test: (a) specimen under splitting tensile; (b) specimen after rupture; (c) specimen under uniaxial compression

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Figure 14
Boxplot of uniaxial compressive strength for mixtures with 4% and 5% cement

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Figure 15
Boxplot of mixtures split tensile strength for mixtures with different contents of cement and silica fume. Note: CXSFY, where X is 4 or 5% (cement content) and Y is 5, 7, or 10% (silica fume content)

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Figure 16
Modulus of elasticity boxplot

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Figure 17
Stress versus strain curves: (a) C5 (5% of cement without silica fume) at 28 days; (b) C5SF10 (5% of cement and 10% of silica fume) at 28 and 91 days.

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Figure 18
Illustration of modulus of elasticity measurement: (a) in compression; (b) in indirect tensile.

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Table 1
Range of cement-bound materials (adapted from York [⁶6 D. York, “Cement-bound materials (CBM),” in Advanced Concrete Technology, vol. 4, J. Newman and B. S. Choo, Eds., Oxford, UK: Elsevier, 2003, pp. 1–12. http://dx.doi.org/10.1016/B978-075065686-3/50309-8.
http://dx.doi.org/10.1016/B978-075065686... ])

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Table 2
Aggregates specific mass

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Table 3
Unit mass for each fraction of aggregates for determination of the real density packing through CPM

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Table 4
Cement characteristics and specifications

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Table 5
Consumption of materials (kg/m³) for CTCS mix design projects

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Table 6
Hypothesis tests for mixtures with 4% and 5% of cement content

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Table 7
ANOVA of the effect of cement and SF content on the indirect tensile strength

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Table 8
t-Student hypothesis test for the difference of mean between samples

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Table 9
Modulus of elasticity and Poisson’s ratio results

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Table 10
t-Student hypothesis test for modulus of elasticity of CTCS

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(2)

(3)

(4)

(5)

(6)

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Type of mixture	Main material	Cement content (by weight)	Strength (7 days)	Cement effect
Cement stabilized soil	Soil	Less than 5%	CBR 15-30%	Partial improvements of material features, such as plasticity, water susceptibility and swelling.
Soil cement	Soil	Over 5%	Compressive strength 1-5 MPa	The crystals generated from the cement hydration create a skeleton which involves the soil particles and fix them, increasing the compressive and tensile strength of the mixture and stiffness as well.
Cement-bound granular materials (CBMG)	Well graded crushed stone	From 3 to 5%	Compressive strength 4-10 MPa	Limited to form connection points between the aggregates since the mortar content is scarce to involve the grains completely.
Lean concrete	Well graded crushed stone	Over 5% and less than 10%	Compressive strength 7-20 MPa	The volume of paste is higher than CBGM materials, creating a material with higher strength and stiffness, but the grading envelope is narrower than CBGM.
Roller compacted concrete (RCC)	Well graded crushed stone	Range from 10 to 17%	Compressive strength > 20 MPa	Relative stiff mixture of aggregates (maximum size not larger than 19 mm). Mixtures should have enough paste volume to fill the internal voids in the aggregate mass. Mixture can be designed regarding two proportioning methods: soil compaction tests and concrete consistency tests (Vebe apparatus). No mandatory enveloped grain size distribution.

Aggregate fraction	Specific mass (kg/m³)
Stone 1	2,670
Stone 0	2,790
Stone dust	2,640

Aggregate diameter (mm)	Unit mass (kg/m³)	Packing density of the fraction
25.0	1,510	0.566
19.0	1,510	0.566
12.5	1,508	0.565
9.5	1,520	0.569
6.3	1,673	0.600
4.8	1,675	0.600
2.0	1,657	0.628
< 2.0	1,720	0.652

Characteristic	CP III SR 40
1-day compressive strength (MPa)	6.6
3-days compressive strength (MPa)	19.6
7-days compressive strength (MPa)	32.1
28-days compressive strength (MPa)	46.7
Initial setting time (min)	200
Blaine specific surface area (cm²)	4,812
Loss of ignition	1.16%
Calcium oxide (CaO)	52.53%
Silica (SiO2)	25.71%
Alumina (Al₂O₃)	8.32%
Iron oxide (Fe₂O₃)	1.91%
Magnesium oxide (MgO)	3.41%
Potassium oxide (K₂O)	0.52%
Sulphate (SO₃)	2.22%
Carbon dioxide (CO₂)	3.18%
Insoluble residue	1.5%

CTCS Mix	Cement	SF	Water	Sand	Gravel	Tests	No. of specimens
4% CPIII SR – C4	95	0	108.57	911.3	1,270.5	f_ct,sp; f_c	12
4% CP III SR + 5% silica fume – C4SF5	95	4.75	106.20	911.3	1,270.5	f_ct,sp	6
4% CP III SR + 7% silica fume – C4SF7	95	6.65	105.25	911.3	1,270.5	f_ct,sp	6
4% CP III SR + 10% silica fume – C4SF10	120	9.5	103.82	911.3	1,270.5	f_ct,sp	6
5% CPIII SR – C5	120	0	108.57	911.3	1,270.5	f_ct,sp; f_c; E modulus	18
5% CP III SR + 5% silica fume – C5SF5	120	6.0	105.57	911.3	1,270.5	f_ct,sp	6
5% CP III SR + 7% silica fume – C5SF5	120	8.4	104.37	911.3	1,270.5	f_ct,sp	6
5% CP III SR + 10% silica fume – C5SF10	120	12.0	102.57	911.3	1,270.5	f_ct,sp; E modulus	12

Parameter	Compressive strength (f_c)		Split tensile strength (f_ct.sp)
Parameter	C4	C5	C4	C5
Mean (MPa)	14.41	17.00	1.70	2.06
Variance (MPa x MPa)	0.310	0.623	0.0146	0.0392
Standard Deviation (MPa)	0.556	0.789	0.121	0.198
Coefficient of variation	3.9%	4.6%	7.1%	9.6%
Test-F
Observations	6		6
Degree of freedom	5		5
F-value	0.497		0.372
p-value	0.230		0.151
F_critical	0.0911		0.0911
Test Result	Unequal variance		Unequal variance
Test-t for mean difference of two samples with unequal variance
Mean difference hypothesis	0		0
Degree of freedom	8		8
Stat-t	-6.563		-3.724
p-value (two tail test)	1.04E-04		5.83E-3
t_critical (two tail test)	3.250		3.355

Source of variation	F-value	p-value	F_critical
Cement content	100.84	1.71E-12	7.314
Silica content	12.22	8.13E-06	4.312
Interactions	1.31	0.283	4.312
α = 0.01

Parameter	C4	C4SF5	C4SF7	C4SF10
Mean	1.70	1.75	1.86	1.93
Variance	0.0146	0.0186	0.0240	0.00973
Standard deviation (MPa)	0.121	0.136	0.155	0.184
Coefficient of variation	7.1%	7.8%	8.3%	9.2%
No. specimens	6	6	6	5^* * Outliers removed from boxplot analysis
Mean difference hypothesis	-	0	0	0
Stat t	-	-0.634	-1.984	-3.417
p-value (two tail test)	-	0.540	0.078	0.00765
t_critical (two tail test)	-	3.169	3.249	3.249

Parameter	C5	C5SF5	C5SF7	C5SF10
Mean	2.06	2.22	2.48	2.59
Variance	0.0392	0.0251	0.0184	0.0173
No. specimens	6	6	6	5*
Mean difference hypothesis	-	0	0	0
Stat t	-	-1.593	-4.381	-5.355
p-value (two tail test)	-	0.142	0.0017	4.59E-4
t_critical (two tail test)	-	3.169	3.249	3.249

Parameter	C4SF7	C5	C5SF7	C5SF10
Mean	1.86	2.06	2.48	2.59
Variance	0.0204	0.0392	0.0184	0.0174
No. specimens	6	6	6	5
Mean difference hypothesis	0		0
Stat t	-1.885		-1.312
p-value (two tail test)	0.092		0.221
t_critical (two tail test)	3.249		3.249

Compressive test
Mixture	Age (days)	# specimens	E (MPa)	sd (MPa)	cv	í	sd	cv
C5SF10	28	6	19,285	966	5%	0.203	0.034	17%
Split Test
Mixture	Age (days)	# specimens	*E_cs* ^* * Secant elastic modulus at 0%-30% of fct,sp; Secant elastic modulus at 30%-100% of fct,sp. (MPa)**	sd (MPa)	cv	E (MPa)**	sd (MPa)	cv
C5SF10	28	3	23,092	1,610	7%	18,508	1,720	9.3%
C5SF10	91	6	24,677	2,715	11%	17,276	1,862	11%
C5	28	6	24,715	3,002	12.1%	17,617	1,189	7%

Parameter	C5	C5SF10 28d^* * Comparison with the reference C5; **Comparison with C5SF10 at 28 days.	C5SF10 91d*	C5SF10 91d^**
Mean	24.715	23.091	24.677	24.677
Variance	9,009,856	2,592,129	7,372,810	7,372,810
# specimens	6	3	6	6
Mean difference hypothesis	-	0	0	0
Stat t	-	-1.056	-0.023	-1.096
p-value (two tail test)	-	0.326	0.982	0.315
t_critical (two tail test)	-	3.499	3.169	3.707

γ_{i} = \frac{β_{i}}{1 - \sum_{j = 1}^{i - 1} [1 - β_{i} + b_{i j} \times β_{i} (1 - \frac{1}{β_{j}})] \times y_{j} - \sum_{j = i + 1}^{n} [1 - a_{i j} \times \frac{β_{j}}{β_{j}}] \times y_{j}}

[1] Corresponding author: Andréia Posser Cargnin. E-mail: andreia.cargnin@usp.br

Brasil

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Inovadora brita graduada tratada com cimento de alto desempenho como concreto compactado com rolo

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