Efeito da duração e pressão da cura por carbonatação do concreto em perfis de cloreto

Dias, Roberto Luiz; Beltrame, Neusa Aparecida Munhak; Gonzalez, Jordi Rius; Medeiros-Junior, Ronaldo Alves

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Revista IBRACON de Estruturas e Materiais

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Sumário

ORIGINAL ARTICLE • Rev. IBRACON Estrut. Mater. 16 (6) • 2023 • https://doi.org/10.1590/S1983-41952023000600003 copiar

Efeito da duração e pressão da cura por carbonatação do concreto em perfis de cloreto

Autoria SCIMAGO INSTITUTIONS RANKINGS

Resumo

A cura por carbonatação altera as características da microestrutura do concreto e pode interferir na penetração de íons agressivos. O objetivo deste artigo foi avaliar a influência da pressão de CO₂ e do tempo de cura da carbonatação nos perfis de cloreto. As amostras de concreto foram curadas por carbonatação com pressões de CO₂ variando de 5 a 25 Psi, por um tempo dentro da câmara de carbonatação de 8, 24 e 36 horas. Esses concretos foram submetidos a 30 ciclos de umedecimento e secagem em solução de NaCl para estimular o ingresso de cloretos. A profundidade de carbonatação e a microestrutura do concreto foram monitoradas ao longo do tempo. Perfis de cloreto foram obtidos e modelados por 4 equações matemáticas. Os resultados mostraram que a combinação de menor tempo e pressão de CO₂ durante a cura por carbonatação potencializou a redução da penetração de cloretos no concreto. Além disso, as condições de cura por carbonatação de 5 e 10 Psi por 8 horas reduziram o coeficiente de difusão do cloreto.

Palavras-chave:
cura por carbonatação; pressão de CO₂; tempo de cura; perfis de cloreto; modelagem

Ref.	Test samples	Pre-cure	Carbonation			Post-cure
Ref.	Test samples	Pre-cure	CO₂ (%)	Pressure (Psi)	Time (h)	Post-cure
[²⁹29 M. Liu, S. Hong, Y. Wanga, J. Zhang, D. Hou, and B. Dong, “Compositions and microstructures of hardened cement paste with carbonation curing and further water curing,” Constr. Build. Mater., vol. 267, pp. 121724, Jan. 2021, http://dx.doi.org/10.1016/j.conbuildmat.2020.121724. http://dx.doi.org/10.1016/j.conbuildmat.... ]	PC paste	18 h sealed and 3 h (2 ± 1) ºC, 50% RH	99.5	14.50	1, 2, 3, 4, 24, and 72	28 days in water
[¹⁵15 L. Qin, X. Gao, A. Su, and Q. Li, “Effect of carbonation curing on sulfate resistance of cement-coal gangue paste,” J. Clean. Prod., vol. 278, pp. 123897, Feb. 2021, http://dx.doi.org/10.1016/j.jclepro.2020.123897. http://dx.doi.org/10.1016/j.jclepro.2020... ]	PC paste	24 h in mold, (20 ± 3) °C	20.0	--	4	28 d, (20 ± 3) °C, RH 90%
[²⁵25 Y. Liu et al., “Properties and microstructure of concrete blocks incorporating drinking water treatment sludge exposed to early-age carbonation curing,” J. Clean. Prod., vol. 261, pp. 121257, July 2020, http://dx.doi.org/10.1016/j.jclepro.2020.121257. http://dx.doi.org/10.1016/j.jclepro.2020... ]	PC Concrete block	4 h, (23 ± 2) ºC, 60% RH	10	--	20	27 days, (23 ± 2) ºC, 95% RH
[¹⁶16 X. Pan, C. Shi, N. Farzadnia, X. Hu, and J. Zheng, “Properties and microstructure of CO2 surface treated cement mortars with subsequent lime-saturated water curing,” Cement Concr. Compos., vol. 99, pp. 89–99, May 2019, http://dx.doi.org/10.1016/j.cemconcomp.2019.03.006. http://dx.doi.org/10.1016/j.cemconcomp.2... ]	PC mortar	24 h in sealed mold, (20 ± 1) °C, RH ≥ 98%	99.0	29.00	3 and 6	28, 90 and 180 days immersed in water
[²⁰20 D. Zhang and Y. Shao, “Enhancing chloride corrosion resistance of precast reinforced concrete by carbonation curing,” ACI Mater. J., vol. 116, pp. 3–12, May 2019., http://dx.doi.org/10.14359/51714461. http://dx.doi.org/10.14359/51714461... ]	PC concrete and cement paste	5 h in mold, 5-6 h 25 °C, RH 50%	99.8	72.52	12	27 days, 25 °C, 95% RH
[²⁴24 J. H. Seo, S. M. Park, and H. K. Lee, “Evolution of the binder gel in carbonation-cured Portland cement in an acidic medium,” Cement Concr. Res., vol. 109, pp. 81–89, July 2018, http://dx.doi.org/10.1016/j.cemconres.2018.03.014. http://dx.doi.org/10.1016/j.cemconres.20... ]	PC paste	24 h in mold, 20 ºC	10	14.69	672	--
[²³23 D. Sharma and S. Goyal, “Accelerated carbonation curing of cement mortars containing cement kiln dust: An effective way of CO2 sequestration and carbon footprint reduction,” J. Clean. Prod., vol. 192, pp. 844–854, Aug. 2018, http://dx.doi.org/10.1016/j.jclepro.2018.05.027. http://dx.doi.org/10.1016/j.jclepro.2018... ]	PC mortar	6 h, 26 ºC, (50 ± 5) % RH	99.0	10.00	12	28 days, sealed and sprinkling water
[⁹9 P. He, C. Shi, Z. Tu, C. S. Poon, and J. Zhang, “Effect of further water curing on compressive strength and microstructure of CO2-cured concrete,” Cement Concr. Compos., vol. 72, pp. 80–88, Sept. 2016, http://dx.doi.org/10.1016/j.cemconcomp.2016.05.026. http://dx.doi.org/10.1016/j.cemconcomp.2... ]	PC mortar and concrete	0-6 h, 22 °C, RH 60%	99.5	29.00	3	27 days immersed in water, 22 ºC
[³⁰30 J. Jang and H. Lee, “Microstructural densification and CO2 uptake promoted by the carbonation curing of belite-rich Portland cement,” Cement Concr. Res., vol. 82, pp. 50–57, Apr. 2016, http://dx.doi.org/10.1016/j.cemconres.2016.01.001. http://dx.doi.org/10.1016/j.cemconres.20... ]	PC mortar and paste	24 h, 20 ºC	5	14.69	168, 336, 672	--
[¹⁰10 L. Mo, F. Zhang, and M. Deng, “Mechanical performance and microstructure of the calcium carbonate binders produced by carbonating steel slag paste under CO2 curing,” Cement Concr. Res., vol. 88, pp. 217–226, Oct. 2016., http://dx.doi.org/10.1016/j.cemconres.2016.05.013. http://dx.doi.org/10.1016/j.cemconres.20... ]	PC paste and steel slag	7 days, (23 ± 2) ºC, 98% RH and 2 days 30-40% RH	99.9	14.69	24, 72, and 336	--
[²⁸28 D. Xuan, B. Zhan, and C. S. Poon, “Development of a new generation of eco-friendly “concrete blocks by accelerated mineral carbonation,” J. Clean. Prod., vol. 133, pp. 1235–1241, Oct. 2016, http://dx.doi.org/10.1016/j.jclepro.2016.06.062. http://dx.doi.org/10.1016/j.jclepro.2016... ]	PC block concrete	6h, 50% RH, 25 ºC	99.5	1.45 to 72.52	1, 2, 3, 6, 18, and 24	28 days air
[¹²12 D. Zhang, X. Cai, and Y. Shao, “Carbonation curing of precast fly ash concrete,” J. Mater. Civ. Eng., vol. 28, no. 11, pp. 04016127, Nov. 2016, http://dx.doi.org/10.1061/(ASCE)MT.1943-5533.0001649. http://dx.doi.org/10.1061/(ASCE)MT.1943-... ]	PC concrete	5 h in the mold and 5.5 h in 25 ºC and (50 ± 5) % RH	99.8	72.52	2, 12, and 24	1, 4, 28, 90, 180, and 360 days, 25 °C, 95% RH
[⁵5 D. Zhang and Y. Shao, “Effect of early carbonation curing on chloride penetration and weathering carbonation in concrete,” Constr. Build. Mater., vol. 123, pp. 516–526, Oct. 2016, http://dx.doi.org/10.1016/j.conbuildmat.2016.07.041. http://dx.doi.org/10.1016/j.conbuildmat.... ]	PC Concrete	5-6 h in mold, 5.5 h 25°C, RH (50 ± 5) %	99.8	72.52	12	27 days, 25 °C, 95% RH
[³¹31 L. Mo and D. K. Panesar, “Effects of accelerated carbonation on the microstructure of Portland cement pastes containing reactive MgO,” Cement Concr. Res., vol. 42, pp. 769–777, June 2012, http://dx.doi.org/10.1016/j.cemconres.2012.02.017. http://dx.doi.org/10.1016/j.cemconres.20... ]	PC paste and reactive MgO	(24 ± 2) h, (23 ± 2) ºC, 90% RH in mold and 24 h, vacuum	99.9	14.69	168, 672, and 1344	--
[²²22 V. Rostami, Y. Shao, A.J. Boyd, “Carbonation curing versus steam curing for precast concrete production”, J. Mater. Civil Eng., vol. 24, n. 9, pp. 1221-1229, Sept., 2012, https://doi.org/10.1061/(ASCE)MT.1943-5533.0000462. https://doi.org/10.1061/(ASCE)MT.1943-55... ]	PC concrete	18 h, 25 °C, RH 60%	99.5	21.75	2	27 days sealed and sprinkling water
[²⁷27 C. Shi, D. Wang, F. He, and M. Liu, “Weathering properties of CO2-cured concrete blocks,” Resour. Conserv. Recycling, vol. 65, pp. 11–17, Aug. 2012, http://dx.doi.org/10.1016/j.resconrec.2012.04.005. http://dx.doi.org/10.1016/j.resconrec.20... ]	Cement block concrete	3-6 h in the mold and 4 h out of the mold	Not indicated	10.00	2	--
[¹⁷17 V. Rostami, Y. Shao, and A. J. Boyd, “Durability of concrete pipes subjected to combined steam and carbonation curing,” Constr. Build. Mater., vol. 25, no. 8, pp. 3345–3355, Aug. 2011, http://dx.doi.org/10.1016/j.conbuildmat.2011.03.025. http://dx.doi.org/10.1016/j.conbuildmat.... ]	Cement block concrete	2 h and 4 h steam (40-63 °C)	99.5	21.75	2	27 days sealed
[²⁶26 T. Saito, S. Khamhou, T. Yumoto, and N. Otsuki, “Permeability of sulfate ions in cementitious materials containing γ-Ca2SiO4 after autoclave curing and accelerated carbonation,” J. Adv. Concr. Technol., vol. 9, pp. 223–230, Oct. 2011., http://dx.doi.org/10.3151/jact.9.223. http://dx.doi.org/10.3151/jact.9.223... ]	PC paste	4 h, 65 ºC, and 100% RH; 8 h autoclave (180 ºC)	5	--	672	--

Property	Unit	CP-II F	Property	Unit	CP-II F
CaO	%	59.51	Specific gravity	g/cm³	3.03
SiO₂	%	16.80	Initial setting time	h:min	03:40
Al₂O₃	%	3.86	Final setting time	h:min	04:30
MgO	%	3.13	Fineness Blaine	cm²/g	3,730
SO₃	%	2.56	# 200	%	0.80
Fe₂O₃	%	2.56	# 325	%	6.70
Loss on ignition	%	10.44	Compressive strength (3 d)	MPa	29.8
Free CaO	%	0.70	Compressive strength (7 d)	MPa	35.2
Insoluble residue	%	0.75	Compressive strength (28 d)	MPa	40.8
Alkaline content (Na₂O and K₂O)	%	0.61

Code	Pressure (Psi)	Time (h)	Code	Pressure (Psi)	Time (h)
5p8h	5	8	20p8h	20	8
5p24h	5	24	20p24h	20	24
5p32h	5	32	20p32h	20	32
10p8h	10	8	25p8h	25	8
10p24h	10	24	25p24h	25	24
10p32h	10	32	25p32h	25	32
15p8h	15	8	REF	-	-
15p24h	15	24
15p32h	15	32

Pressure	Depth of carbonation (mm)			Mass increment CO₂ (%)			Absorption (%)
Pressure	8 h	24 h	32 h	8 h	24 h	32 h	8 h	24 h	32 h
5 Psi	11.63	17.51	22.54	6.46	11.48	15.19	4.1	5.2	4.9
10 Psi	9.42	14.65	20.52	7.55	10.42	11.56	5.3	6.6	6.0
15 Psi	12.92	21.58	20.57	6.98	13.01	13.63	4.5	4.8	6.2
20 Psi	13.92	17.87	22.43	7.76	10.37	10.97	4.3	6.0	6.4
25 Psi	14.87	20.44	21.87	8.43	10.97	12.44	5.1	5.4	6.1

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[1] Corresponding author: Neusa Aparecida Munhak Beltrame. E-mail: neusamunhakbeltrame@gmail.com